February 12, 2024 • 41 mins
Embark on an intoxicating voyage through the storied groves of apple history and the intricate science of cider with Dr. Greg Peck from Cornell's School of Integrative Plant Science. Prepare your palate for a revelation as we uncover why cider apples bear little resemblance to their grocery store relatives, and how a symphony of tannins, sugars, and acidity beautifully ferment into the cider that elevates our dining experiences. Greg's expertise illuminates the journey from orchard to glass, revealing the transformative art that turns simple apples into complex beverages with every press and ferment. Our conversation is a rich blend of natural chemistry and meticulous craft, sure to deepen your appreciation for cider's robust charm.
This episode also delves into the practical research that guides orchard optimization—think sunlight exposure, phenolic development, and the pivotal role of nitrogen in fermentation. It's a masterclass in managing apple varieties and maximizing yields to shape the future of fine cider.
Read the HortTechnology article "Growing Apples for Hard Cider Production in the United States—Trends and Research Opportunities" at https://doi.org/10.21273/HORTTECH04488-19.
The HortScience article "Fruitlet Thinning Improves Juice Quality in Seven High-tannin Cider Cultivars" is available at https://doi.org/10.21273/HORTSCI17096-23 and "Fruitlet Thinning Reduces Biennial Bearing in Seven High-tannin Cider Apple Cultivars" is at https://doi.org/10.21273/HORTSCI17455-23.
Additional information about Dr. Greg Peck is available at https://cals.cornell.edu/gregory-michael-peck.
Learn more about the American Society for Horticultural Science (ASHS) at https://ashs.org/.
HortTechnology, HortScience and the Journal of the American Society for Horticultural Science are all open-access and peer-reviewed journals, published by the American Society of Horticultural Science (ASHS). Find them at journals.ashs.org.
Consider becoming an ASHS member at https://ashs.org/page/Becomeamember!
You can also find the official webpage for Plants, People, Science at ashs.org/plantspeoplesciencepodcast, and we encourage you to send us feedback or suggestions at https://ashs.org/webinarpodcastsuggestion.
Podcast transcripts are available at https://plantspeoplescience.buzzsprout.com.
On LinkedIn find Sam Humphrey at linkedin.com/in/samson-humphrey. Curt Rom is at https://www.linkedin.com/in/curt-rom-611085134/. Lena Wilson is at https://www.linkedin.com/in/lena-wilson-2531a5141/.
Thank you for listening!
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Sam Humphrey (00:11):
Welcome to 'Plants People Science', a podcast by
the American Society forHorticultural Science, where we
talk about all thingshorticulture.
In today's episode, we discusscider and the amazing science
and people that bring us thiswonderful drink.
Today, we have a very specialguest, Dr.
Greg Peck, who is an associateprofessor at Cornell's School of
Integrative Plant Science.
(00:31):
In 2018, the American CiderAssociation named him Grower
Advocate of the Year and heteaches several cider and
orchard management classesalongside his fascinating
research.
Dr Peck, welcome to the show.
Greg Peck (00:43):
Hi Sam, good morning.
Curt Rom (00:45):
Hey Dr Peck.
This is Curt Rom.
I've got a question for you forthe conversation today.
Would you like us to call youDr Peck, or would you like us to
call you Greg?
What are you most comfortablewith?
Greg Peck (00:57):
Let's use Greg, I think, a nice casual tone.
Okay if I call you Curt and Sam?
Curt Rom (01:04):
That'd be great.
Sam Humphrey (01:05):
Absolutely.
Greg, in your words, what doyou do?
Greg Peck (01:11):
Well, yeah, that's a great question for an academic.
We'll be here for days.
My official job title withCornell is associate professor.
I have a 60% researchappointment, 30% teaching and
10% extension.
Within my research program I doseveral projects.
(01:33):
We're going to talk today aboutthe cider research, but I also
work in organic apple systems, Ido some work in sustainability
and also crop load managementfor apples using some modeling
work with pollen tube growth.
Curt Rom (01:49):
Greg, today I think we'd like to focus in on the
part of your work on cider.
"Cider" is kind of a short word.
It's a small word but it seemsto have kind of big implication,
big meaning.
When we say cider, what do wemean?
What do you mean when you say"cider Great?
Greg Peck (02:07):
Great question, Curt, because it does have a lot of
different meanings.
I think traditionally in theUnited States "cider" meant a
sweet, unfermented juice.
It came right off of press,i usually brown and cloudy.
In the northeastern US it was abig part of a lot of the
average tourism Traditionally.
here in the you- pickoperations and you go and pick
(02:27):
apples, get cider, get ciderapple donuts.
donuts U nfermented juice.
Today we think about cider moreas a fermented beverage.
And so cider has a long, longhistory dating back centuries in
Europe.
It's where apple juice isfermented, usually by yeast --
(02:51):
always by yeast, I guess -- andthe sugar gets converted to
alcohol.
So you have an alcoholicproduct.
Some people will refer to it ashard cider.
Many parts of Europe, they justcall it cider.
There's some back and forth inthe industry whether hard cider
has this kind of negativeconnotation, "hard being
something that maybe isn't apositive attribute.
(03:14):
There's some producers say wejust want to call it cider, not
hard cider.
Today in our conversation whenwe say cider, we are talking
about the fermented product.
Curt Rom (03:24):
Okay, thanks a lot.
In preparation for today.
I was reading several of yourarticles and you've been very
prolific in publishing aboutcider apple production.
The cultivars that you talkabout are not familiar with me.
I don't see them at the grocerystore.
So what differentiates a ciderapple and a good cider apple
from the apples I see at thegrocery store -- the fresh
(03:47):
market, the consumable, theedible and cookable apples?
Greg Peck (03:52):
Right.
So cider apples are a verydifficult subset of apples to
define, because all applescontain sugar, and so yeast can
convert the juice from any appleinto alcohol and you'd have
hard cider.
(04:12):
However, there is a subset ofapples that have very specific
chemical attributes that makethem uniquely purpose- driven
for making hard cider.
And so this might be theirsugar content.
They have higher sugar, so youget a higher alcohol content.
(04:32):
That might be their acidity,and so you get a product that's
sharper or more sour, whichlends a little bit more of a
backbone to the finished cider.
Or what's really interesting tous in our program, and what's
really interesting to a lot ofthe cider producers, is they
might have a very highconcentration of a subset of
phenolics or polyphenols calledtannins, and these are the ones
(04:57):
that the compounds that lend toreally make a robust product.
Makes it bitter or astringent,depending on the specific types
of tannins in the product.
But for a fresh eating apple,high concentration of tannin
would be very unpleasant, and sooftentimes the cider producers
(05:19):
will call these spitters,because once you take a bite out
of the fresh apple, you want tospit it out of your mouth as
quickly as possible.
Sam Humphrey (05:27):
That sounds traumatic.
I don't want ever to eat anapple like that! But cider is
delicious.
So there are many factors, then, that go into making these
apples good for cider production.
But on top of that there's alsothe post-harvest treatments.
There's here's and pressing andfermentation.
How does all that change theflavor of cider?
Greg Peck (05:50):
Well, it's very dramatic, and we'll probably
over the course of ourconversation today, try to draw
on analogies to wine production,because I think a lot of cider
production is very much similarto wine production.
So grapes have juice in them.
You have to somehow extractthat juice, and then the yeast
(06:10):
will ferment the sugar in thatjuice into wine.
And we know, though, that whenyou eat a grape, it doesn't
taste like wine.
The flavor composition changesdramatically over the
fermentation process and thefinished product.
For the most part, especiallyfor the Vitis vinifera ( the
European wine grapes) are verydifferent between juice and wine
(06:32):
.
The same is true for cider.
When you're, if you have sweetcider, the unfermented product,
it's not going to taste the sameas the fermented cider.
That's because the flavorvolatiles change.
You might have some changes inaromatics and you might have
some changes in the acid and thephenolic composition over the
(06:53):
course of fermentation and alsoaging.
When we look for characteristicsfor what do we want for cider
apple right, because I'm ahorticulturalist, of course, and
that's what we're here to talkabout, I'm on the apple
production side we always haveto kind of think about okay,
well, what is this juice goingto be like in fermentation and
(07:16):
what's going to be like afterfermentation.
It's really important and it'smaybe something that, when we
think about apple qualityattributes and a lot of the
research that goes into how dowe improve apple quality for
commercial production we're alsothinking about peel color,
(07:37):
fruit size maybe, and for thebreeding angle might be
crispiness, right, we have a tonof apples now that are crisp,
this crisp, that, or the sugaracid balance in there.
But for cider production wehave other characteristics as
well that we're really trying tohone in on.
So it's different.
There's a lot to draw on, butdifferent.
Sam Humphrey (07:59):
With decades, centuries of experience of
literature talking about howpeople are making this cider and
what sorts of apples work thebest.
There's a very rich historythere.
Would you give us anabbreviated history of cider in
America?
Greg Peck (08:16):
Yeah, so cider in America.
When the European colonistsfirst arrived here, they
definitely wanted alcohol, right, well, other than the Puritans,
after the Puritans, maybe.
And so where humans go,typically alcohol follows, and
(08:36):
they did try to bring over Vitis vinifera.
A lot of those grapevinesfailed because we have
phylloxera.
Phylloxera is actuallyendemic to North America and
it's one of our tests that pestsreleased into the world, and
it's an invasive pest in manyother parts of the world.
So a lot of those grapevinesperished.
(08:57):
They did eventually figure outhow to grow apples here in North
America, and cider became justpart of the landscape, in terms
of both physical landscape butalso the culinary landscape in
the Eastern US, right, a lot offarms would have cider apple
(09:18):
trees, they would produce cider.
It was a very localizedproduction.
Sometimes it was used incommerce, but mostly just for
household use, or sometimes justvery much so a local thing.
Fast forward, you know,centuries.
We get up to the late 1800s.
(09:41):
We start having a temperancemovement, people started to see
the ills of alcohol consumptionand we had prohibition in the
early 1900s.
And so one of the famous kindof mythologies about prohibition
is that the prohibitionists,the temperance movement, went
around chopping down all theapple trees because they were
(10:03):
being used for making cider.
And it probably happened tosome extent, maybe not as much
as the mythology says.
Certainly it was some famouspictures of it that really
dramatized that.
But coming out of prohibition,what happened is that not only
did we have a shift in our kindof view of alcohol consumption
(10:28):
but we also had a shift in ourdemographics in the country.
We had a lot of immigrationfrom Northern Europe, places
like Ireland and Germany, beerdrinking countries, and after
prohibition, instead of havingan agricultural society, an
agrarian society, we started tomove towards a more urban
society.
So it's a lot easier to makebeer for urban masses because
(10:51):
it's grain, right.
Beer is made from a grain.
You can store it year round.
You can transport that grain;it doesn't have a very much
water content.
Transport it into urban centersand make beer where the people
are.
So cider largely died away.
If it wasn't prohibition, it wasreally certainly those
demographic changes thathappened and also the change in
(11:12):
our economic structure in ourcountry after prohibition.
So that was in the 1930s and itreally wasn't until the 1990s,
60- 70 years later, that westarted to see a few producers
say, hey, we can also makealcohol from apples, we should
(11:33):
try this.
So we had a few cider producersstarting in the '90s and then
in the 2000s we started to see Ithink it probably ties into
some of the local food movement,some of the change in
demographics where people wantto try different things and new
foods, and we started to see aresurgence about 20 years ago in
(11:57):
cider production production, sonow cider is produced by nearly
1,400 different companiesaround the US in all 50 states,
including Alaska, Hawaii, Texas.
I mean there's ciders in allthese places and for retail
sales it's probably somewherearound a $1.5 billion industry.
Curt Rom (12:25):
That's an interesting story.
Yeah, even in the state ofArkansas and the turn of the
20th century, going 19th to 20thcentury, our large industry was
built on either cider apples,brandy apples or drying apples,
which is interesting.
So, there's this resurgence inthe 1990s, Greg Peck is
(12:48):
finishing a PhD, how you getinvolved in -- What caused the
interest in you starting to workon cider apples?
Because I've been in this andthere's not a lot of us
pomologists that have focused onthat market.
What got you into it?
Greg Peck (13:10):
It really started when I was at my first tenure
track job at Virginia Tech and Igot contacted.
I had a 50-50 researchextension split so I worked a
lot with the growers in thestate on a lot of different
issues around pomology and appleproduction, mostly for the
fresh market.
But I got contacted by a few ofthem within a year or two of
(13:34):
being there and saying, "ey,we're getting calls from some of
our local cideries and theywant us to plant these weird
varieties that we've never heardof.
Should we do it?
" And I said, wow, geez, I don'tknow, let's try to figure this
out.
And so we started offcollaborating with an ag
economist.
We did some cost of productionstudies.
(13:55):
That was really where westarted.
What's the economic feasibility?
The growers wanted to know, isthis economically feasible?
And those results were reallyfavorable and the calls kept
coming to the apple growerssaying, "ey, we want this
variety, we want that variety.
All of a sudden it was "we wantso many different varieties
because the cider producersdidn't really understand the
(14:17):
horticultural traits of these,and so they just said, "oh,
we've read about this, we'veread about that, we want these
varieties.
So the next series of studiesand really it's still ongoing
was about cultivar evaluation.
We say, okay, well, there's aprice premium for these and the
demand is high, the supply islow and now we have to figure
(14:41):
out which ones of these ciderapple cultivars should we really
be growing in Virginia andcontinue that work in my current
job at Cornell.
Curt Rom (14:51):
That's an interesting start.
So now you're knee- deep intocider, cider- barrel deep, I
guess.
As you have emerged yourself inthe science, what are some of
the big questions?
What are the research questions?
You know, what are things -- Iknow there can be both grower
questions that are researchable,but also, I'm sure, now that
(15:12):
you've been working on this fora decade plus, you see some
deeper questions.
So what are the questions?
What?
Where's the research edge?
Greg Peck (15:21):
Yeah, we have several lines of research in my lab and
you know many of them areapplied.
Just because you know some ofthis, you know we haven't no
one's really, as you said, Curt,no one's really touched this
topic for 100 years plus in ourcountry or really around the
world.
We're starting to see a lotmore research everywhere,
(15:43):
including other researchers inthe US, which is exciting.
But in terms of my lab, we havequestions around, I mentioned
the tannins and the polyphenols,a subset of polyphenols that
lend to mouth feel androbustness to a product.
And so now we're reallyinterested to understand what
(16:05):
pre-harvest factors can affectfruit quality, therefore juice
quality, cider quality.
So I look at a lot of this verysimilar to again going back to
the analogy with grapes and wine, as what viticulture is to wine
production, right?
What are the factors that wecan manipulate in an orchard
that will affect cider quality?
So, from the very basic side,we just have to understand, like
(16:29):
when do phenolics form inapples?
Right?
There hasn't been a lot ofresearch on that.
What controls polyphenolproduction in apples?
Right?
So there's been research onthis, looking at it from a
nutraceutical, from a humanhealth perspective, but you know
we're talking about apples forcider production that have 10
(16:50):
plus times the level of thesecompounds, and so a lot of the
work that we're doing is showingthat the phenolics developed
very early in the season,typically right at, maybe at the
point of fertilization, rightas soon as cell division really
starts.
All the way up through thatcell division phase, that first
(17:12):
30, 45 days after bloom is whenwe're seeing a lot of these
phenolics develop.
And then it kind of is adilution question.
As cells enlarge, they get morewater and they might change a
bit in composition.
And we're actually studyingthat right now to try to figure
out.
You know, they polymerizingmore or we're getting some
different types of phenolicsdeveloping later in the season.
(17:38):
And then on top of that we askquestions about, you know, what
factors might change thatconcentration or composition.
So we look at things like cropload, right, of course, crop
load.
For apples, crop load is soimportant and you know we find
very strong correlations betweenhow many apples are on an apple
(17:58):
tree and the concentration ofphenolics in the apples
themselves.
Right, there's a real dilutioneffect.
The more apples you have, thelower the phenolic content.
So what causes that?
Right, that's the question, andso we're still trying to look
at that.
We know that it's related tocrop load.
Is it a source- sinkrelationship?
Is it about the carbonreallocation in the tree?
(18:21):
Is it other factors genes beingup- or down- regulated, that
you know, in response to carbonavailability or response to some
other factors?
We're getting pretty deep intothose questions right now in my
lab.
Curt Rom (18:38):
Sounds like typical biology.
Both nature and nurture areimportant here, yeah, for sure.
Greg Peck (18:44):
And so besides for crop load.
We also look at things likesunlight, and so we've done a
lot of projects over the lastfive, six years, shading
different whole trees, shadingdifferent organs on the tree.
If we just shade an appleversus the apple and the spur
leaves, the apple, the spurleaves and the whole grooming
shoot.
You know, we're trying toreally understand and get at
(19:06):
some of these source- sinkrelationships.
So that's one line ofquestioning.
We have a whole other line ofquestioning too, looking at
nitrogen, right.
So we're a horticulturalists,we're always, you know, go for
the big things that are going tocontrol a lot of things in
plants, right carbon andnitrogen.
And so nitrogen, interestingly,is another very specific thing
(19:29):
related to cider, which is thatand again back to the analogy
with grapes is that one of theattributes, one of the quality
attributes for cider beforefermentation is the amount of
yeast-assimilable nitrogen orYAN, and this is something that
wine producers talk a lot about,because yeast need that
(19:52):
nitrogen for their metabolism.
In addition, if nitrogencontent, if the YAN content,
(the yeast-assimilable nitrogencontent or YAN content), is low,
the yeast, what they'll do is,through respiration, we'll start
depositing electrons on sulfurcompounds as opposed to nitrogen
, because they've reduced allthe nitrogen, and then they have
(20:13):
to get rid of their electronsright through respiration
somehow, and so they'll startreducing sulfur.
So reduced sulfur, or hydrogensulfide, is the same compound
that natural gas companies putinto their natural gas so that
it smells like rotten eggs couldbe skunky.
Clearly this is a fault, right?
(20:36):
This is something that we'dfind unpleasant in the finished
product.
So apples, by and large, have alower concentration of nitrogen
than grapes do, and so this isadding all sorts of new research
questions about how do weincrease the nitrogen content in
apples, but also what yeaststrains, right?
(20:58):
So we work a little bit withthe knowledge of this.
What yeast strains are there?
The yeast strains that are moreadaptable to low nitrogen
environments, and that kind ofthing.
So a whole bunch of line ofquestioning along those around
nitrogen as well.
Curt Rom (21:15):
I have a production question for you.
It's not really pomological,but maybe it is so in the
fermentation process.
Do fermenters add yeast or arethese surface- native, surface
indigenous yeasts?
And so the pomological questionis: are there factors, are
(21:35):
there things that we would dofrom the production standpoint
that would change the indigenousyeast population, the surface
yeast population, if that'simportant in the fermentation
process?
Again, I'm ignorant about it.
You gotta fill me in, tell me.
Greg Peck (21:50):
Man, this is a great question because this is really
a hot button issue for the ciderindustry right now.
Again, analogies to the wineindustry.
The kind of standard process orprotocol would be that the
cider producer would add sulfite(SO2) to their juice before
(22:15):
fermentation, which woulddecrease significantly the yeast
population, the native yeastpopulation, and then they would
inoculate with a commercialstrain of yeast and then allow
the fermentation to proceed.
But there's this whole subsetof the industry that wants to do
natural fermentation orspontaneous fermentation would
(22:38):
be another name for that whichis allowing, as you said, the
yeast that were either in theorchard or oftentimes in the
press room or on the pressingequipment to allow those yeast
strains to become the dominantstrain in fermentation.
And it's a little bit less of acontrolled process but
something that a lot of oursmaller scale I'd say some of
(23:01):
our medium scale producers aredoing in order to allow.
Either it's a philosophicalreason for doing it right,
because they believe in the morenatural process of that, or
believe that it is a morenatural process, whereas I think
for a lot of our larger scaleproducers they wanna make sure
(23:23):
that they have a reliableproduct that's gonna be the same
any day of the year in anygiven year, right, and so they
wanna be able to control it.
So we haven't actually done anywork looking at what kind of
pre-harvest factors might affectyeast diversity in orchards,
(23:44):
but there's a few people workingon that topic.
I think we'll probably discoversome interesting things over
time.
There were a few papers thatcame out of France a number of
years ago where they do somenatural fermentations or
spontaneous fermentations, andwhat was really interesting was
(24:05):
that the yeast strains and thespontaneous fermentations turned
out to be identical to thecommercial strains, even though
no commercial inoculationhappened.
And that's because they werethe yeast strains that were
colonizing everything around andthat's probably why they became
commercialized is because theyare out competing their cousins
(24:29):
and becoming the dominant strainin the environment and also in
the fermentation.
So it'll be fun to see if thesimilar story is true for cider.
Sam Humphrey (24:42):
You know it's a bit surreal to me because we're
talking and I'm learning aboutthe chemistry and the sulfites
and the yeast strains, andyou're going so in depth into
plant physiology, and yet here'sa video there's of you giving
an orchard tour and you beingvery involved with growers.
(25:02):
And I'm really fascinated bythe idea of systems thinking in
what you do.
I'm curious if you could giveyour thoughts on the importance
of systems thinking inhorticulture.
Greg Peck (25:13):
Yeah, thanks, Sam, for that question.
I think that really you know theidea of thinking about
agricultural production as asystem is something that you
know.
Maybe I came into my PhD or mygraduate work and my master's in
PhD with.
Certainly it's something thatevolved during that time,
studying organic andconventional systems and
(25:35):
comparing them and knowing thatno one practice, no one
management strategy in anorchard is gonna tell you the
whole story, and so I've alwaysbeen interested in the whole
picture and I think thatprobably comes through in my
cider research too, where I kindof touch on different topics.
Some of that is thinking like agrower, thinking like what are
(25:55):
the growers and answeringquestions from them and trying
to just keep up with whatgrowers have to think about,
right, Cause they're alwaysabout the system right, they're
never just about one aspect ofan orchard.
And I think, because of thenewness of cider apple research
in our country and really aroundthe world, it allows me to kind
(26:20):
of apply some of the systemsthinking and try to figure out,
okay, what are the key questions, when can we actually make some
positive contributions to thescience but also to the
producers and answer somequestions for them?
Sam Humphrey (26:36):
Fantastic.
It seems like you must also beteaching this in your classes,
right?
You teach multiple ciderclasses, and how does that work:
teaching such a varied class toa group of students?
Greg Peck (26:52):
Yeah.
So we teach two classes relatedto cider production
specifically at Cornell and wedo it through the viticulture
and enology major, and our ciderlecture is a 2000 level class.
It's open to students in theirfirst through fourth year or
beyond.
We get a few grad students inthere.
(27:14):
And it's really a bit of ciderappreciation.
We do tastings almost everyclass where they'll taste three
or four different products.
Or sometimes it's doctor edproducts where we've added
certain products, compounds todisplay faults, right.
(27:34):
We might add a lot of hydrogensulfide, for example, so they
can really get a sense of whatthat rotten egg smell is.
We do some regional tastingswhat are ciders from Spain like,
what are ciders from Francelike and some of the, because
they have some unique productioncharacteristics that really
typify their styles of cider.
(27:55):
It's fun.
We do it in a very large lecturehall that was designed for wine
tasting and now cider tasting.
That allows the TAs to walkbetween the rows and pour ciders
and we typically get 100, 110students in that class.
What's great about it is Ico-teach it with my colleague,
(28:16):
Kathy Arnink, and she's amicrobiologist by training and
she's an enologist and so I getto teach everything, probably
about the industry, but a lotabout apple production, up until
the point that the apples willget milled and pressed into
juice and then I pass the mic tomy colleague.
And Kathy then will teach aboutfermentation and the
(28:39):
microbiology and all the thingsthat are in her wheelhouse.
So it's a really nicepartnership.
The students get a lot out ofit.
I think we, as a general-interest 2000 level class, we
get students from all over theuniversity take it, and so we're
always -- Kathy and I arealways -- trying to slip in as
much science as possible.
Well, we know that the studentsare there to taste cider.
Curt Rom (29:04):
I want to go back and ask a production question again.
You know I've never worked withcider apples.
I do like cider, just to beclear about that.
So I'm a consumer, but I'venever worked with them
scientifically.
But as a pomologist you knowcrop load means a lot and so
there's this kind of -- Iapologize for the pun-- sweet
(29:25):
spot in crop load that we canoptimize crop load, maximize
fruit size, maximize fruitflavor, which usually means,
currently means sweetness.
So from a cider growerperspective, what is the
question?
Is it quantity of apples on atree to increase production or
(29:49):
is it the quality of thoseapples?
And is there a sour spot forcider, just like there's a sweet
spot for edible apples?
Greg Peck (30:02):
A lot of the cider apples that producers are trying
to grow in the United Statescome out of Europe and a lot of
these apple cultivars were --and I'll use variety and
cultivar synonymously.
ASHS likes us to use cultivarin our written work, and the
growers always want us to usevariety, and so sometimes I slip
(30:23):
back and forth just fordefinition terms.
But a lot of these cidercultivars were selected 100 plus
years ago for systems wherethey were being grown in like
standard sized trees that mighthave been 25, 30 plus feet tall
and they were grazing animalsheep or cows underneath it:
(30:46):
very imprecise sort ofproduction systems.
Whatever came in any given yearwould be what they harvested,
and the apples were typicallyharvested off of the ground.
So having a propensity forpre-harvest fruit drop was not a
negative quality attribute likeit is with our culinary apples
today, and so a lot of theseapple cultivars tend to be very
(31:11):
biennial, meaning they'll have ayear with a lot of fruit,
naturally, and then the nextyear with little to no fruit,
and they have these large swings.
Well, that's fine in you know,100 years ago for these very
kind of low input systems thatwere feeding into, you know,
farmhouse production.
(31:33):
But in modern business wereally can't go a year without a
crop, or certainly evensometimes if there's a product
that has a specific you know mixof certain varieties or
cultivars that they want inthere, they have to have those
reliably right.
(31:53):
So now the question is how dowe grow these really kind of
wonky varieties right in amodern production system and a
high density system and cropthem annually?
And so it always is, Curt, aquestion of quantity and quality
.
Right, it always is, and that'strue for culinary apples,
that's true for wine grapes andit's certainly true for cider
(32:15):
apples.
So some of our recent researchthat we actually just published
HortScience for ASHS.
We published two papers out ofDavid Zakalik's master's work
where we did three years ofstudy looking at the different
levels of crop load, and weidentified crop load or defined
(32:35):
crop load as the number ofapples per trunk cross-sectional
area, which is a nice metric tokind of regardless of the tree
size.
Physiologically they had thesame fruit to vegetative biomass
ratio, or at least that's whatwe strive for.
It's not precise but it's close.
And so we created a whole rangeof different crop loads on
(32:57):
these trees over three years.
Did the same trees, the samecrop load, and then we looked at
things like the biennialbearing habit, the total yields
and a lot of the fruit and juicequality attributes.
So lots of details in there.
I encourage you to go readthose papers, because I think
they're really well-written andDavid did a really great job on
(33:20):
his master's and on thosepublications from his master's
work on those.
But the take-home was that wecould probably crop a lot of
these varieties, about twice asmuch as we do our culinary
apples.
We'll still have some biennialbearing, but we can drastically
reduce the biennial bearing.
So instead of having theseswings with all production and
(33:43):
no production, we get into thein-between.
There's still going to be someswings, but when we look at it
cumulatively over the long termwe find that the cumulative
yield per acre or hectare islarger at somewhere around nine
fruit per trunk cross-sectionalarea and that also then will
(34:06):
kind of balance between thehighest fruit quality or juice
quality is at the lowest croploads.
That's probably impractical froma economic standpoint, right,
and then the lowest juicequality, t he worst juice
quality, is when we over cropthe trees.
They had a ton of apples onthem, ,but poor quality.
So we did a little bit ofhand-waving and kind of looked
(34:29):
at all this data from hisresearch and came up with the
number we're just trying to givegrowers some guidance at about
nine fruit per trunkcross-sectional area for a lot
of our cider apples.
So by comparison, Honeycrisp, alot of growers are shooting for
about four fruit percross-sectional area.
Gala, probably about six in ourclimate fruit per
(34:52):
cross-sectional area.
So we're going, you know,sometimes up to twice as much
fruit as our culinary apples.
Sam Humphrey (34:59):
Wow, that's incredible, and we will include
links to those papers in theshow notes.
I do want to mention that thoseare in both of them are in Hort
Science, is that correct?
Curt Rom (35:09):
Correct, yes, and they're really good papers and
it's always impressive to me.
You know, when you put togethera good scientist mentor and a
good graduate student, greatwork happens.
So I really enjoyed thosepapers and congratulations on
your co-author and the student.
It shows that you can a studentcan really make a difference to
(35:29):
our science.
Greg Peck (35:32):
Oh, 100%.
I mean Sam asked earlier about,you know, my job and what I do
and you know I said I can talkfor hours and days on this, but
a big part of what we do ismentoring and training graduate
students and training newscientists to get into the field
, and it's probably one of thehardest things that we do but
also one of the most rewardingin the end.
Sam Humphrey (35:56):
So, wrapping up here, I am struck that there's a
lot, it seems like there's alot to be excited about.
There's exciting researchresearchy ou described, and I'm
sure, many questions that youdidn't even mention that are
exciting.
There are reasons to be excitedwith teaching and with the
different areas of outreach andresearch in terms of yeasts and
(36:22):
fermentation and so manydifferent fields.
I'm curious, leaving off, whatare you excited about, Dr Peck?
Greg Peck (36:30):
Boy.
Great question.
What's next?
What am I really excited by?
So we have some new work comingout about mechanical harvesting
, which is kind of a practicethat's been widely used in
Europe for harvesting ciderapples, and it's something that
(36:51):
really helps with the laborissues.
In our country we have hugepolitical issues and also
economic issues around harvestlabor, so most of our apples in
the US are hand harvested.
Might be changing down the roadwith robots, but we can
certainly harvest apples a lotmore roughly than we can fresh
(37:13):
market apples.
We can handle some bruising incider apples because they're
going to get milled and pressedinto juice.
So that's an area of researchthat we're excited by is trying
to figure out.
Now we've identified somevarieties, we're identifying
some management techniques.
Now we have to make it costeffective to grow these really
unique apples that we know makea really fantastic cider right,
(37:34):
these robust ciders, thesereally great quality attributes.
But we need to continually lookat okay, how do we do this cost
effectively?
So mechanization is going to bea big part of that, and I'm also
excited by what I'm seeingacross the country with cider
research, and so, outside of myprogram, a lot of great cider
(37:57):
research has happened byWashington State University, and
a big shout out to Carol Milesand her program there.
We work a lot together ondifferent projects.
She's been working a lot onmechanical harvesting over the
years as well, but many otherland grant universities around
the country are starting to seethat their growers are
interested in cider apples, thatthey're diversifying.
(38:18):
One really super excitingthing, Sam, is, and I would love
for an anthropologist orsociologist to get involved in
this with us, is we're seeing areturn to the farm from the next
generation, where, for yearsyears we always heard, oh, it's
hard to get the family farm tokeep going and have that
(38:41):
sustainability to the nextgeneration because the kids
don't want to do it.
"They want to go and make money
doing finance or computerscience or whatever.
Maybe they want to go into art,but they're not going back to
the farm.
And we're seeing, in New Yorkat least, there's a lot of
examples where the nextgeneration is coming back to the
family farm.
They say well, you know, I'minterested in apple production,
(39:03):
but I'm really interested incider production and are really
growing that industry there.
So that's also exciting too isbecause that speaks well for
longevity and kind ofgenerational profitability.
The cost of startup of a newfood or beverage business is so
(39:24):
high and the turnover rate isreally high as well.
Like, 50% failure rate.
And we haven't seen nearly thathigh in cider, but there's
always that concern.
And so that kind ofgenerational and vertical
integrated systems or verticallyintegrated businesses being
developed is super exciting.
So a little bit outside of mywheelhouse research, but
(39:47):
something you can tell.
I'm excited to see this becauseit means like, okay, we're
doing this work and it's goingto mean something down the road
too, right, we're not justworking on a fad, but we're
working on something that isgoing to be here for the future.
Curt Rom (40:02):
Well, Greg, this has been really interesting and I
really appreciate your timetoday.
You know our listeners might beinterested in your work, so I
think they can find you.
You have a very good website.
If you "Google Greg PeckCornell," or Greg Peck Cider,
you'll go to your lab.
Now I want to tell ourlisteners and I've waited the
(40:22):
whole time don't Google GregoryPeck, because you'll get to the
wrong star.
We're really talking about thepomological star Greg Peck,
Cornell University, our ciderexpert in the United States.
But it was a great conversation.
I learned a whole lot.
Greg Peck (40:38):
Thanks, Curt, Really appreciate your time.
Thanks Sam.
Sam Humphrey (40:42):
Thank you, Greg.
To read more about cider applesand their history, check out a
paper co-authored by Greg titled"Growing Apples for Hard Cider
Production in the United States: Trends and Research (40:49):
undefined
Opportunities.
" It covers the fascinatingtrends and challenges in cider
production and explains the manydifferences between American
and European cider productionpractices.
This paper is published inHortTechnology, one of the
open-source peer-reviewedjournals published by the
American Society forHorticultural Science.
A link to this article and theothers we talked about during
(41:12):
the episode will be provided inthe show notes.
Curt Rom (41:16):
And again, as I said, if you want to learn more about
Greg and his work, you can findhis bio at the Cornell website
or you can find him featured inan article in modernfarmer.
com.
Sam Humphrey (41:26):
If this interview resonates with you, I highly
recommend renewing yourmembership and joining the
American Society forHorticultural Science so you can
be a part of interest groupslike Pomology or Post-Harvest or
Fruit Breeding.
If you'd like more informationabout the American Society for
Horticultural Science in general, you can go to ashs.
org.
Curt Rom (41:46):
Thank you, Sam.
Thank you for listening today.
Welcome to 'Plants People Science', a podcast by
the American Society forHorticultural Science, where we
talk about all thingshorticulture.
In today's episode, we discusscider and the amazing science
and people that bring us thiswonderful drink.
Today, we have a very specialguest, Dr.
Greg Peck, who is an associateprofessor at Cornell's School of
Integrative Plant Science.
(00:31):
In 2018, the American CiderAssociation named him Grower
Advocate of the Year and heteaches several cider and
orchard management classesalongside his fascinating
research.
Dr Peck, welcome to the show.
Greg Peck (00:43):
Hi Sam, good morning.
Curt Rom (00:45):
Hey Dr Peck.
This is Curt Rom.
I've got a question for you forthe conversation today.
Would you like us to call youDr Peck, or would you like us to
call you Greg?
What are you most comfortablewith?
Greg Peck (00:57):
Let's use Greg, I think, a nice casual tone.
Okay if I call you Curt and Sam?
Curt Rom (01:04):
That'd be great.
Sam Humphrey (01:05):
Absolutely.
Greg, in your words, what doyou do?
Greg Peck (01:11):
Well, yeah, that's a great question for an academic.
We'll be here for days.
My official job title withCornell is associate professor.
I have a 60% researchappointment, 30% teaching and
10% extension.
Within my research program I doseveral projects.
(01:33):
We're going to talk today aboutthe cider research, but I also
work in organic apple systems, Ido some work in sustainability
and also crop load managementfor apples using some modeling
work with pollen tube growth.
Curt Rom (01:49):
Greg, today I think we'd like to focus in on the
part of your work on cider.
"Cider" is kind of a short word.
It's a small word but it seemsto have kind of big implication,
big meaning.
When we say cider, what do wemean?
What do you mean when you say"cider Great?
Greg Peck (02:07):
Great question, Curt, because it does have a lot of
different meanings.
I think traditionally in theUnited States "cider" meant a
sweet, unfermented juice.
It came right off of press,i usually brown and cloudy.
In the northeastern US it was abig part of a lot of the
average tourism Traditionally.
here in the you- pickoperations and you go and pick
(02:27):
apples, get cider, get ciderapple donuts.
donuts U nfermented juice.
Today we think about cider moreas a fermented beverage.
And so cider has a long, longhistory dating back centuries in
Europe.
It's where apple juice isfermented, usually by yeast --
(02:51):
always by yeast, I guess -- andthe sugar gets converted to
alcohol.
So you have an alcoholicproduct.
Some people will refer to it ashard cider.
Many parts of Europe, they justcall it cider.
There's some back and forth inthe industry whether hard cider
has this kind of negativeconnotation, "hard being
something that maybe isn't apositive attribute.
(03:14):
There's some producers say wejust want to call it cider, not
hard cider.
Today in our conversation whenwe say cider, we are talking
about the fermented product.
Curt Rom (03:24):
Okay, thanks a lot.
In preparation for today.
I was reading several of yourarticles and you've been very
prolific in publishing aboutcider apple production.
The cultivars that you talkabout are not familiar with me.
I don't see them at the grocerystore.
So what differentiates a ciderapple and a good cider apple
from the apples I see at thegrocery store -- the fresh
(03:47):
market, the consumable, theedible and cookable apples?
Greg Peck (03:52):
Right.
So cider apples are a verydifficult subset of apples to
define, because all applescontain sugar, and so yeast can
convert the juice from any appleinto alcohol and you'd have
hard cider.
(04:12):
However, there is a subset ofapples that have very specific
chemical attributes that makethem uniquely purpose- driven
for making hard cider.
And so this might be theirsugar content.
They have higher sugar, so youget a higher alcohol content.
(04:32):
That might be their acidity,and so you get a product that's
sharper or more sour, whichlends a little bit more of a
backbone to the finished cider.
Or what's really interesting tous in our program, and what's
really interesting to a lot ofthe cider producers, is they
might have a very highconcentration of a subset of
phenolics or polyphenols calledtannins, and these are the ones
(04:57):
that the compounds that lend toreally make a robust product.
Makes it bitter or astringent,depending on the specific types
of tannins in the product.
But for a fresh eating apple,high concentration of tannin
would be very unpleasant, and sooftentimes the cider producers
(05:19):
will call these spitters,because once you take a bite out
of the fresh apple, you want tospit it out of your mouth as
quickly as possible.
Sam Humphrey (05:27):
That sounds traumatic.
I don't want ever to eat anapple like that! But cider is
delicious.
So there are many factors, then, that go into making these
apples good for cider production.
But on top of that there's alsothe post-harvest treatments.
There's here's and pressing andfermentation.
How does all that change theflavor of cider?
Greg Peck (05:50):
Well, it's very dramatic, and we'll probably
over the course of ourconversation today, try to draw
on analogies to wine production,because I think a lot of cider
production is very much similarto wine production.
So grapes have juice in them.
You have to somehow extractthat juice, and then the yeast
(06:10):
will ferment the sugar in thatjuice into wine.
And we know, though, that whenyou eat a grape, it doesn't
taste like wine.
The flavor composition changesdramatically over the
fermentation process and thefinished product.
For the most part, especiallyfor the Vitis vinifera ( the
European wine grapes) are verydifferent between juice and wine
(06:32):
.
The same is true for cider.
When you're, if you have sweetcider, the unfermented product,
it's not going to taste the sameas the fermented cider.
That's because the flavorvolatiles change.
You might have some changes inaromatics and you might have
some changes in the acid and thephenolic composition over the
(06:53):
course of fermentation and alsoaging.
When we look for characteristicsfor what do we want for cider
apple right, because I'm ahorticulturalist, of course, and
that's what we're here to talkabout, I'm on the apple
production side we always haveto kind of think about okay,
well, what is this juice goingto be like in fermentation and
(07:16):
what's going to be like afterfermentation.
It's really important and it'smaybe something that, when we
think about apple qualityattributes and a lot of the
research that goes into how dowe improve apple quality for
commercial production we're alsothinking about peel color,
(07:37):
fruit size maybe, and for thebreeding angle might be
crispiness, right, we have a tonof apples now that are crisp,
this crisp, that, or the sugaracid balance in there.
But for cider production wehave other characteristics as
well that we're really trying tohone in on.
So it's different.
There's a lot to draw on, butdifferent.
Sam Humphrey (07:59):
With decades, centuries of experience of
literature talking about howpeople are making this cider and
what sorts of apples work thebest.
There's a very rich historythere.
Would you give us anabbreviated history of cider in
America?
Greg Peck (08:16):
Yeah, so cider in America.
When the European colonistsfirst arrived here, they
definitely wanted alcohol, right, well, other than the Puritans,
after the Puritans, maybe.
And so where humans go,typically alcohol follows, and
(08:36):
they did try to bring over Vitis vinifera.
A lot of those grapevinesfailed because we have
phylloxera.
Phylloxera is actuallyendemic to North America and
it's one of our tests that pestsreleased into the world, and
it's an invasive pest in manyother parts of the world.
So a lot of those grapevinesperished.
(08:57):
They did eventually figure outhow to grow apples here in North
America, and cider became justpart of the landscape, in terms
of both physical landscape butalso the culinary landscape in
the Eastern US, right, a lot offarms would have cider apple
(09:18):
trees, they would produce cider.
It was a very localizedproduction.
Sometimes it was used incommerce, but mostly just for
household use, or sometimes justvery much so a local thing.
Fast forward, you know,centuries.
We get up to the late 1800s.
(09:41):
We start having a temperancemovement, people started to see
the ills of alcohol consumptionand we had prohibition in the
early 1900s.
And so one of the famous kindof mythologies about prohibition
is that the prohibitionists,the temperance movement, went
around chopping down all theapple trees because they were
(10:03):
being used for making cider.
And it probably happened tosome extent, maybe not as much
as the mythology says.
Certainly it was some famouspictures of it that really
dramatized that.
But coming out of prohibition,what happened is that not only
did we have a shift in our kindof view of alcohol consumption
(10:28):
but we also had a shift in ourdemographics in the country.
We had a lot of immigrationfrom Northern Europe, places
like Ireland and Germany, beerdrinking countries, and after
prohibition, instead of havingan agricultural society, an
agrarian society, we started tomove towards a more urban
society.
So it's a lot easier to makebeer for urban masses because
(10:51):
it's grain, right.
Beer is made from a grain.
You can store it year round.
You can transport that grain;it doesn't have a very much
water content.
Transport it into urban centersand make beer where the people
are.
So cider largely died away.
If it wasn't prohibition, it wasreally certainly those
demographic changes thathappened and also the change in
(11:12):
our economic structure in ourcountry after prohibition.
So that was in the 1930s and itreally wasn't until the 1990s,
60- 70 years later, that westarted to see a few producers
say, hey, we can also makealcohol from apples, we should
(11:33):
try this.
So we had a few cider producersstarting in the '90s and then
in the 2000s we started to see Ithink it probably ties into
some of the local food movement,some of the change in
demographics where people wantto try different things and new
foods, and we started to see aresurgence about 20 years ago in
(11:57):
cider production production, sonow cider is produced by nearly
1,400 different companiesaround the US in all 50 states,
including Alaska, Hawaii, Texas.
I mean there's ciders in allthese places and for retail
sales it's probably somewherearound a $1.5 billion industry.
Curt Rom (12:25):
That's an interesting story.
Yeah, even in the state ofArkansas and the turn of the
20th century, going 19th to 20thcentury, our large industry was
built on either cider apples,brandy apples or drying apples,
which is interesting.
So, there's this resurgence inthe 1990s, Greg Peck is
(12:48):
finishing a PhD, how you getinvolved in -- What caused the
interest in you starting to workon cider apples?
Because I've been in this andthere's not a lot of us
pomologists that have focused onthat market.
What got you into it?
Greg Peck (13:10):
It really started when I was at my first tenure
track job at Virginia Tech and Igot contacted.
I had a 50-50 researchextension split so I worked a
lot with the growers in thestate on a lot of different
issues around pomology and appleproduction, mostly for the
fresh market.
But I got contacted by a few ofthem within a year or two of
(13:34):
being there and saying, "ey,we're getting calls from some of
our local cideries and theywant us to plant these weird
varieties that we've never heardof.
Should we do it?
" And I said, wow, geez, I don'tknow, let's try to figure this
out.
And so we started offcollaborating with an ag
economist.
We did some cost of productionstudies.
(13:55):
That was really where westarted.
What's the economic feasibility?
The growers wanted to know, isthis economically feasible?
And those results were reallyfavorable and the calls kept
coming to the apple growerssaying, "ey, we want this
variety, we want that variety.
All of a sudden it was "we wantso many different varieties
because the cider producersdidn't really understand the
(14:17):
horticultural traits of these,and so they just said, "oh,
we've read about this, we'veread about that, we want these
varieties.
So the next series of studiesand really it's still ongoing
was about cultivar evaluation.
We say, okay, well, there's aprice premium for these and the
demand is high, the supply islow and now we have to figure
(14:41):
out which ones of these ciderapple cultivars should we really
be growing in Virginia andcontinue that work in my current
job at Cornell.
Curt Rom (14:51):
That's an interesting start.
So now you're knee- deep intocider, cider- barrel deep, I
guess.
As you have emerged yourself inthe science, what are some of
the big questions?
What are the research questions?
You know, what are things -- Iknow there can be both grower
questions that are researchable,but also, I'm sure, now that
(15:12):
you've been working on this fora decade plus, you see some
deeper questions.
So what are the questions?
What?
Where's the research edge?
Greg Peck (15:21):
Yeah, we have several lines of research in my lab and
you know many of them areapplied.
Just because you know some ofthis, you know we haven't no
one's really, as you said, Curt,no one's really touched this
topic for 100 years plus in ourcountry or really around the
world.
We're starting to see a lotmore research everywhere,
(15:43):
including other researchers inthe US, which is exciting.
But in terms of my lab, we havequestions around, I mentioned
the tannins and the polyphenols,a subset of polyphenols that
lend to mouth feel androbustness to a product.
And so now we're reallyinterested to understand what
(16:05):
pre-harvest factors can affectfruit quality, therefore juice
quality, cider quality.
So I look at a lot of this verysimilar to again going back to
the analogy with grapes and wine, as what viticulture is to wine
production, right?
What are the factors that wecan manipulate in an orchard
that will affect cider quality?
So, from the very basic side,we just have to understand, like
(16:29):
when do phenolics form inapples?
Right?
There hasn't been a lot ofresearch on that.
What controls polyphenolproduction in apples?
Right?
So there's been research onthis, looking at it from a
nutraceutical, from a humanhealth perspective, but you know
we're talking about apples forcider production that have 10
(16:50):
plus times the level of thesecompounds, and so a lot of the
work that we're doing is showingthat the phenolics developed
very early in the season,typically right at, maybe at the
point of fertilization, rightas soon as cell division really
starts.
All the way up through thatcell division phase, that first
(17:12):
30, 45 days after bloom is whenwe're seeing a lot of these
phenolics develop.
And then it kind of is adilution question.
As cells enlarge, they get morewater and they might change a
bit in composition.
And we're actually studyingthat right now to try to figure
out.
You know, they polymerizingmore or we're getting some
different types of phenolicsdeveloping later in the season.
(17:38):
And then on top of that we askquestions about, you know, what
factors might change thatconcentration or composition.
So we look at things like cropload, right, of course, crop
load.
For apples, crop load is soimportant and you know we find
very strong correlations betweenhow many apples are on an apple
(17:58):
tree and the concentration ofphenolics in the apples
themselves.
Right, there's a real dilutioneffect.
The more apples you have, thelower the phenolic content.
So what causes that?
Right, that's the question, andso we're still trying to look
at that.
We know that it's related tocrop load.
Is it a source- sinkrelationship?
Is it about the carbonreallocation in the tree?
(18:21):
Is it other factors genes beingup- or down- regulated, that
you know, in response to carbonavailability or response to some
other factors?
We're getting pretty deep intothose questions right now in my
lab.
Curt Rom (18:38):
Sounds like typical biology.
Both nature and nurture areimportant here, yeah, for sure.
Greg Peck (18:44):
And so besides for crop load.
We also look at things likesunlight, and so we've done a
lot of projects over the lastfive, six years, shading
different whole trees, shadingdifferent organs on the tree.
If we just shade an appleversus the apple and the spur
leaves, the apple, the spurleaves and the whole grooming
shoot.
You know, we're trying toreally understand and get at
(19:06):
some of these source- sinkrelationships.
So that's one line ofquestioning.
We have a whole other line ofquestioning too, looking at
nitrogen, right.
So we're a horticulturalists,we're always, you know, go for
the big things that are going tocontrol a lot of things in
plants, right carbon andnitrogen.
And so nitrogen, interestingly,is another very specific thing
(19:29):
related to cider, which is thatand again back to the analogy
with grapes is that one of theattributes, one of the quality
attributes for cider beforefermentation is the amount of
yeast-assimilable nitrogen orYAN, and this is something that
wine producers talk a lot about,because yeast need that
(19:52):
nitrogen for their metabolism.
In addition, if nitrogencontent, if the YAN content,
(the yeast-assimilable nitrogencontent or YAN content), is low,
the yeast, what they'll do is,through respiration, we'll start
depositing electrons on sulfurcompounds as opposed to nitrogen
, because they've reduced allthe nitrogen, and then they have
(20:13):
to get rid of their electronsright through respiration
somehow, and so they'll startreducing sulfur.
So reduced sulfur, or hydrogensulfide, is the same compound
that natural gas companies putinto their natural gas so that
it smells like rotten eggs couldbe skunky.
Clearly this is a fault, right?
(20:36):
This is something that we'dfind unpleasant in the finished
product.
So apples, by and large, have alower concentration of nitrogen
than grapes do, and so this isadding all sorts of new research
questions about how do weincrease the nitrogen content in
apples, but also what yeaststrains, right?
(20:58):
So we work a little bit withthe knowledge of this.
What yeast strains are there?
The yeast strains that are moreadaptable to low nitrogen
environments, and that kind ofthing.
So a whole bunch of line ofquestioning along those around
nitrogen as well.
Curt Rom (21:15):
I have a production question for you.
It's not really pomological,but maybe it is so in the
fermentation process.
Do fermenters add yeast or arethese surface- native, surface
indigenous yeasts?
And so the pomological questionis: are there factors, are
(21:35):
there things that we would dofrom the production standpoint
that would change the indigenousyeast population, the surface
yeast population, if that'simportant in the fermentation
process?
Again, I'm ignorant about it.
You gotta fill me in, tell me.
Greg Peck (21:50):
Man, this is a great question because this is really
a hot button issue for the ciderindustry right now.
Again, analogies to the wineindustry.
The kind of standard process orprotocol would be that the
cider producer would add sulfite(SO2) to their juice before
(22:15):
fermentation, which woulddecrease significantly the yeast
population, the native yeastpopulation, and then they would
inoculate with a commercialstrain of yeast and then allow
the fermentation to proceed.
But there's this whole subsetof the industry that wants to do
natural fermentation orspontaneous fermentation would
(22:38):
be another name for that whichis allowing, as you said, the
yeast that were either in theorchard or oftentimes in the
press room or on the pressingequipment to allow those yeast
strains to become the dominantstrain in fermentation.
And it's a little bit less of acontrolled process but
something that a lot of oursmaller scale I'd say some of
(23:01):
our medium scale producers aredoing in order to allow.
Either it's a philosophicalreason for doing it right,
because they believe in the morenatural process of that, or
believe that it is a morenatural process, whereas I think
for a lot of our larger scaleproducers they wanna make sure
(23:23):
that they have a reliableproduct that's gonna be the same
any day of the year in anygiven year, right, and so they
wanna be able to control it.
So we haven't actually done anywork looking at what kind of
pre-harvest factors might affectyeast diversity in orchards,
(23:44):
but there's a few people workingon that topic.
I think we'll probably discoversome interesting things over
time.
There were a few papers thatcame out of France a number of
years ago where they do somenatural fermentations or
spontaneous fermentations, andwhat was really interesting was
(24:05):
that the yeast strains and thespontaneous fermentations turned
out to be identical to thecommercial strains, even though
no commercial inoculationhappened.
And that's because they werethe yeast strains that were
colonizing everything around andthat's probably why they became
commercialized is because theyare out competing their cousins
(24:29):
and becoming the dominant strainin the environment and also in
the fermentation.
So it'll be fun to see if thesimilar story is true for cider.
Sam Humphrey (24:42):
You know it's a bit surreal to me because we're
talking and I'm learning aboutthe chemistry and the sulfites
and the yeast strains, andyou're going so in depth into
plant physiology, and yet here'sa video there's of you giving
an orchard tour and you beingvery involved with growers.
(25:02):
And I'm really fascinated bythe idea of systems thinking in
what you do.
I'm curious if you could giveyour thoughts on the importance
of systems thinking inhorticulture.
Greg Peck (25:13):
Yeah, thanks, Sam, for that question.
I think that really you know theidea of thinking about
agricultural production as asystem is something that you
know.
Maybe I came into my PhD or mygraduate work and my master's in
PhD with.
Certainly it's something thatevolved during that time,
studying organic andconventional systems and
(25:35):
comparing them and knowing thatno one practice, no one
management strategy in anorchard is gonna tell you the
whole story, and so I've alwaysbeen interested in the whole
picture and I think thatprobably comes through in my
cider research too, where I kindof touch on different topics.
Some of that is thinking like agrower, thinking like what are
(25:55):
the growers and answeringquestions from them and trying
to just keep up with whatgrowers have to think about,
right, Cause they're alwaysabout the system right, they're
never just about one aspect ofan orchard.
And I think, because of thenewness of cider apple research
in our country and really aroundthe world, it allows me to kind
(26:20):
of apply some of the systemsthinking and try to figure out,
okay, what are the key questions, when can we actually make some
positive contributions to thescience but also to the
producers and answer somequestions for them?
Sam Humphrey (26:36):
Fantastic.
It seems like you must also beteaching this in your classes,
right?
You teach multiple ciderclasses, and how does that work:
teaching such a varied class toa group of students?
Greg Peck (26:52):
Yeah.
So we teach two classes relatedto cider production
specifically at Cornell and wedo it through the viticulture
and enology major, and our ciderlecture is a 2000 level class.
It's open to students in theirfirst through fourth year or
beyond.
We get a few grad students inthere.
(27:14):
And it's really a bit of ciderappreciation.
We do tastings almost everyclass where they'll taste three
or four different products.
Or sometimes it's doctor edproducts where we've added
certain products, compounds todisplay faults, right.
(27:34):
We might add a lot of hydrogensulfide, for example, so they
can really get a sense of whatthat rotten egg smell is.
We do some regional tastingswhat are ciders from Spain like,
what are ciders from Francelike and some of the, because
they have some unique productioncharacteristics that really
typify their styles of cider.
(27:55):
It's fun.
We do it in a very large lecturehall that was designed for wine
tasting and now cider tasting.
That allows the TAs to walkbetween the rows and pour ciders
and we typically get 100, 110students in that class.
What's great about it is Ico-teach it with my colleague,
(28:16):
Kathy Arnink, and she's amicrobiologist by training and
she's an enologist and so I getto teach everything, probably
about the industry, but a lotabout apple production, up until
the point that the apples willget milled and pressed into
juice and then I pass the mic tomy colleague.
And Kathy then will teach aboutfermentation and the
(28:39):
microbiology and all the thingsthat are in her wheelhouse.
So it's a really nicepartnership.
The students get a lot out ofit.
I think we, as a general-interest 2000 level class, we
get students from all over theuniversity take it, and so we're
always -- Kathy and I arealways -- trying to slip in as
much science as possible.
Well, we know that the studentsare there to taste cider.
Curt Rom (29:04):
I want to go back and ask a production question again.
You know I've never worked withcider apples.
I do like cider, just to beclear about that.
So I'm a consumer, but I'venever worked with them
scientifically.
But as a pomologist you knowcrop load means a lot and so
there's this kind of -- Iapologize for the pun-- sweet
(29:25):
spot in crop load that we canoptimize crop load, maximize
fruit size, maximize fruitflavor, which usually means,
currently means sweetness.
So from a cider growerperspective, what is the
question?
Is it quantity of apples on atree to increase production or
(29:49):
is it the quality of thoseapples?
And is there a sour spot forcider, just like there's a sweet
spot for edible apples?
Greg Peck (30:02):
A lot of the cider apples that producers are trying
to grow in the United Statescome out of Europe and a lot of
these apple cultivars were --and I'll use variety and
cultivar synonymously.
ASHS likes us to use cultivarin our written work, and the
growers always want us to usevariety, and so sometimes I slip
(30:23):
back and forth just fordefinition terms.
But a lot of these cidercultivars were selected 100 plus
years ago for systems wherethey were being grown in like
standard sized trees that mighthave been 25, 30 plus feet tall
and they were grazing animalsheep or cows underneath it:
(30:46):
very imprecise sort ofproduction systems.
Whatever came in any given yearwould be what they harvested,
and the apples were typicallyharvested off of the ground.
So having a propensity forpre-harvest fruit drop was not a
negative quality attribute likeit is with our culinary apples
today, and so a lot of theseapple cultivars tend to be very
(31:11):
biennial, meaning they'll have ayear with a lot of fruit,
naturally, and then the nextyear with little to no fruit,
and they have these large swings.
Well, that's fine in you know,100 years ago for these very
kind of low input systems thatwere feeding into, you know,
farmhouse production.
(31:33):
But in modern business wereally can't go a year without a
crop, or certainly evensometimes if there's a product
that has a specific you know mixof certain varieties or
cultivars that they want inthere, they have to have those
reliably right.
(31:53):
So now the question is how dowe grow these really kind of
wonky varieties right in amodern production system and a
high density system and cropthem annually?
And so it always is, Curt, aquestion of quantity and quality
.
Right, it always is, and that'strue for culinary apples,
that's true for wine grapes andit's certainly true for cider
(32:15):
apples.
So some of our recent researchthat we actually just published
HortScience for ASHS.
We published two papers out ofDavid Zakalik's master's work
where we did three years ofstudy looking at the different
levels of crop load, and weidentified crop load or defined
(32:35):
crop load as the number ofapples per trunk cross-sectional
area, which is a nice metric tokind of regardless of the tree
size.
Physiologically they had thesame fruit to vegetative biomass
ratio, or at least that's whatwe strive for.
It's not precise but it's close.
And so we created a whole rangeof different crop loads on
(32:57):
these trees over three years.
Did the same trees, the samecrop load, and then we looked at
things like the biennialbearing habit, the total yields
and a lot of the fruit and juicequality attributes.
So lots of details in there.
I encourage you to go readthose papers, because I think
they're really well-written andDavid did a really great job on
(33:20):
his master's and on thosepublications from his master's
work on those.
But the take-home was that wecould probably crop a lot of
these varieties, about twice asmuch as we do our culinary
apples.
We'll still have some biennialbearing, but we can drastically
reduce the biennial bearing.
So instead of having theseswings with all production and
(33:43):
no production, we get into thein-between.
There's still going to be someswings, but when we look at it
cumulatively over the long termwe find that the cumulative
yield per acre or hectare islarger at somewhere around nine
fruit per trunk cross-sectionalarea and that also then will
(34:06):
kind of balance between thehighest fruit quality or juice
quality is at the lowest croploads.
That's probably impractical froma economic standpoint, right,
and then the lowest juicequality, t he worst juice
quality, is when we over cropthe trees.
They had a ton of apples onthem, ,but poor quality.
So we did a little bit ofhand-waving and kind of looked
(34:29):
at all this data from hisresearch and came up with the
number we're just trying to givegrowers some guidance at about
nine fruit per trunkcross-sectional area for a lot
of our cider apples.
So by comparison, Honeycrisp, alot of growers are shooting for
about four fruit percross-sectional area.
Gala, probably about six in ourclimate fruit per
(34:52):
cross-sectional area.
So we're going, you know,sometimes up to twice as much
fruit as our culinary apples.
Sam Humphrey (34:59):
Wow, that's incredible, and we will include
links to those papers in theshow notes.
I do want to mention that thoseare in both of them are in Hort
Science, is that correct?
Curt Rom (35:09):
Correct, yes, and they're really good papers and
it's always impressive to me.
You know, when you put togethera good scientist mentor and a
good graduate student, greatwork happens.
So I really enjoyed thosepapers and congratulations on
your co-author and the student.
It shows that you can a studentcan really make a difference to
(35:29):
our science.
Greg Peck (35:32):
Oh, 100%.
I mean Sam asked earlier about,you know, my job and what I do
and you know I said I can talkfor hours and days on this, but
a big part of what we do ismentoring and training graduate
students and training newscientists to get into the field
, and it's probably one of thehardest things that we do but
also one of the most rewardingin the end.
Sam Humphrey (35:56):
So, wrapping up here, I am struck that there's a
lot, it seems like there's alot to be excited about.
There's exciting researchresearchy ou described, and I'm
sure, many questions that youdidn't even mention that are
exciting.
There are reasons to be excitedwith teaching and with the
different areas of outreach andresearch in terms of yeasts and
(36:22):
fermentation and so manydifferent fields.
I'm curious, leaving off, whatare you excited about, Dr Peck?
Greg Peck (36:30):
Boy.
Great question.
What's next?
What am I really excited by?
So we have some new work comingout about mechanical harvesting
, which is kind of a practicethat's been widely used in
Europe for harvesting ciderapples, and it's something that
(36:51):
really helps with the laborissues.
In our country we have hugepolitical issues and also
economic issues around harvestlabor, so most of our apples in
the US are hand harvested.
Might be changing down the roadwith robots, but we can
certainly harvest apples a lotmore roughly than we can fresh
(37:13):
market apples.
We can handle some bruising incider apples because they're
going to get milled and pressedinto juice.
So that's an area of researchthat we're excited by is trying
to figure out.
Now we've identified somevarieties, we're identifying
some management techniques.
Now we have to make it costeffective to grow these really
unique apples that we know makea really fantastic cider right,
(37:34):
these robust ciders, thesereally great quality attributes.
But we need to continually lookat okay, how do we do this cost
effectively?
So mechanization is going to bea big part of that, and I'm also
excited by what I'm seeingacross the country with cider
research, and so, outside of myprogram, a lot of great cider
(37:57):
research has happened byWashington State University, and
a big shout out to Carol Milesand her program there.
We work a lot together ondifferent projects.
She's been working a lot onmechanical harvesting over the
years as well, but many otherland grant universities around
the country are starting to seethat their growers are
interested in cider apples, thatthey're diversifying.
(38:18):
One really super excitingthing, Sam, is, and I would love
for an anthropologist orsociologist to get involved in
this with us, is we're seeing areturn to the farm from the next
generation, where, for yearsyears we always heard, oh, it's
hard to get the family farm tokeep going and have that
(38:41):
sustainability to the nextgeneration because the kids
don't want to do it.
"They want to go and make money
doing finance or computerscience or whatever.
Maybe they want to go into art,but they're not going back to
the farm.
And we're seeing, in New Yorkat least, there's a lot of
examples where the nextgeneration is coming back to the
family farm.
They say well, you know, I'minterested in apple production,
(39:03):
but I'm really interested incider production and are really
growing that industry there.
So that's also exciting too isbecause that speaks well for
longevity and kind ofgenerational profitability.
The cost of startup of a newfood or beverage business is so
(39:24):
high and the turnover rate isreally high as well.
Like, 50% failure rate.
And we haven't seen nearly thathigh in cider, but there's
always that concern.
And so that kind ofgenerational and vertical
integrated systems or verticallyintegrated businesses being
developed is super exciting.
So a little bit outside of mywheelhouse research, but
(39:47):
something you can tell.
I'm excited to see this becauseit means like, okay, we're
doing this work and it's goingto mean something down the road
too, right, we're not justworking on a fad, but we're
working on something that isgoing to be here for the future.
Curt Rom (40:02):
Well, Greg, this has been really interesting and I
really appreciate your timetoday.
You know our listeners might beinterested in your work, so I
think they can find you.
You have a very good website.
If you "Google Greg PeckCornell," or Greg Peck Cider,
you'll go to your lab.
Now I want to tell ourlisteners and I've waited the
(40:22):
whole time don't Google GregoryPeck, because you'll get to the
wrong star.
We're really talking about thepomological star Greg Peck,
Cornell University, our ciderexpert in the United States.
But it was a great conversation.
I learned a whole lot.
Greg Peck (40:38):
Thanks, Curt, Really appreciate your time.
Thanks Sam.
Sam Humphrey (40:42):
Thank you, Greg.
To read more about cider applesand their history, check out a
paper co-authored by Greg titled"Growing Apples for Hard Cider
Production in the United States: Trends and Research (40:49):
undefined
Opportunities.
" It covers the fascinatingtrends and challenges in cider
production and explains the manydifferences between American
and European cider productionpractices.
This paper is published inHortTechnology, one of the
open-source peer-reviewedjournals published by the
American Society forHorticultural Science.
A link to this article and theothers we talked about during
(41:12):
the episode will be provided inthe show notes.
Curt Rom (41:16):
And again, as I said, if you want to learn more about
Greg and his work, you can findhis bio at the Cornell website
or you can find him featured inan article in modernfarmer.
com.
Sam Humphrey (41:26):
If this interview resonates with you, I highly
recommend renewing yourmembership and joining the
American Society forHorticultural Science so you can
be a part of interest groupslike Pomology or Post-Harvest or
Fruit Breeding.
If you'd like more informationabout the American Society for
Horticultural Science in general, you can go to ashs.
org.
Curt Rom (41:46):
Thank you, Sam.
Thank you for listening today.
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