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Cider Digest #1435
Subject: Cider Digest #1435, 29 January 2008
From: cider-request@talisman.com
Cider Digest #1435 29 January 2008
Forum for Discussion of Cider Issues
Dick Dunn, Digest Janitor
Contents:
Apple rootstocks (Jack O Feil)
Re: Cider Digest #1434, 24 January 2008 (Bill Rhyne)
Fermentation Speed and Fruit Age (Andrew Lea)
Backsweetening with concentrate (joseph margevicius)
2008 Upper Mississippi Mash-Out results are posted ("Crist, Jonathan")
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Subject: Apple rootstocks
From: Jack O Feil <feilorchards@juno.com>
Date: Thu, 24 Jan 2008 15:12:51 -0800
I grow apples commercially and there is a nice selection from the Malling
and Bud series. I know nothing about the Geneva s, so I will continue to
use the rootstocks with which I am familiar. I find very little if any
information on the Geneva series, so if it ain't broke don't fix it.
------------------------------
Subject: Re: Cider Digest #1434, 24 January 2008
From: Bill Rhyne <bill_rhyne@yahoo.com>
Date: Thu, 24 Jan 2008 17:55:26 -0800 (PST)
RE: Scott Smith's question regarding fruit tasting as a predictor of cider
potential
I think that Scott is correct and it is consistent with my experience.
Chefs and winemakers like to taste their ingredients to evaluate the
potential for processing. Much of the flavor of mild flavored apples is
lost in fermentation so it is necessary to find apples whose flavor can
survive the process. Tart apples like Granny Smiths offer acid but no
tannin, not much aroma, and not much flavor. A ripe apple offers the
requisite sugar for fermentation purposes. So, the challenge is find
tannic apples and apples with nice aromas that can be blended with the
lightly flavored apples. One can train his or her taste buds over time to
identify the flavors. When we were first evaluating ciders and trying to
teach ourselves with Rhyne Cyder, I would buy a variety of apples from
the local markets and farmers. We would cut the apples up, smell them,
observe the flesh color to see if there was a browning (evidence of tannin),
and then taste them for sweetness, tannin, and sugar flavors.
Some of juice of these apples when tasted during juicing process was so
thick, sweet, and flavorful that one glass was a satisfying as a whole meal.
It ruined me for apple juice sold in the stores.
Anyway, you are on the right path!
Bill Rhyne
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Subject: Fermentation Speed and Fruit Age
From: Andrew Lea <andrew_lea@compuserve.com>
Date: Sat, 26 Jan 2008 11:17:31 +0000
Con wrote:
> [the effect of protein as opposed to free amino acid versions of N on
> fermentation speed] Do you think we could gather any more evidence
> from the literature or experiment to make this Lea's theory, or
> better still, Lea's law.
I think we might call it "Andrew's assumption" but I think that's as far
as it should go!! I have done something of a search in the computer
accessible literature (i.e. back to about 1970) but found nothing. The
info about protein N in stored apple increasing at the expense of free
amino N is originally from the 1930's, and only referred to in a quaint
and obsolete form of information storage and transmission which we used
to call "textbooks" (remember them?)!!
Claude wrote:
>> the yeast needs assimilable nitrogen (readily supplied by amino acids or
>>> ammonium salts) to make protein for its own growth
> and:
>>> Yeast also needs the nitrogen-containing vitamin thiamin (vitamin
>>> B1) which plays an essential role as a co-factor during
>>> fermentation particularly in the final enzymic conversion of
>>> pyruvate to ethanol
> What is a co-factor, Andrew?
A co-factor is something an enzyme needs to allow it to do its job
properly.
> Is it right to conclude from the above that N is not essential in the
> chemical reactions for the transformation of a sugar molecule into
> alcool and CO2, but it is essential in the life cycle of the yeast
> organisms that make the transformation?
Pretty much. Yeasts, like us, need amino nitrogen (amino acids) to build
protein to grow and to form their enzymes which are also proteins. They
also need some nitrogen-containing vitamins to function properly. We can
break down protein in our stomachs to obtain the free amino acids to
re-assemble into new proteins - some fermenting yeasts can do this at a
pinch but generally it is not a route that they 'prefer'.
> Another related question - How do the yeast use N? Do they somewhat
> consume it and make unavailable for other use, or is it like a
> catalist where N is used, then released and used again? This is an
> important issue since if N is transformed into a useless compound
> (e.g. as a protein) by the yeast, then if there is a limited amount
> of N available at fermentation start, it would explain the phenomenon
> of stuck fermentation. On the other hand, if N is used as a catalist,
> it would reduce fermentation speed if in short supply, but would not
> stop it.
The amino N is indeed transformed into protein by the yeast. I would not
call it 'useless' since it provides the 'body' of the yeast and also its
enzymes, but certainly once it is locked up it is unavailable to any
other yeast cell until that cell dies and 'autolyses' and releases
nutrients back into the cider.
The most common cause of a stuck fermentation is either a lack of free
amino nitrogen (which inhibits yeast growth) or a lack of thiamin (which
inhibits the fermentation pathway). Most yeast nutrients contain both
these things.
> My intuition is that it is the first of the above statements that is
> the right one (i.e. N is transformed into a useless protein during
> fermentation). And, interestingly, the same phenomenon would occur in
> the ripening apples - the amino acids (containing usable N) are
> transformed into useless proteins!
The odd thing is exactly why the maturing apple should convert free
amino nitrogen into 'useless' protein. It's not at all clear what the
'purpose' of this is since the fruit has finished growing anyway. And
there is no information so far as I know on exactly which proteins are
being synthesized. Proteins have so many different roles and functions.
> Maybe we have something here that merits a little more digging. For
> those of us that are interested in keeving and slow fermentation, it
> could be worth making some experimentation with overripe apples vs
> apples in their prime, keeve both batches side by side and note
> differences in fermentation speed.
I suggest you put it on your list for next year, Claude!
Andrew
- --
Wittenham Hill Cider Page
http://www.cider.org.uk
------------------------------
Subject: Backsweetening with concentrate
From: joseph margevicius <jmargevicius@hotmail.com>
Date: Mon, 28 Jan 2008 17:42:01 +0000
I have several batches of cider fermenting to complete dryness; some
are from pure apple juice, some had fruit (peach, raspberry, strawberry)
added to apple juice during the fermentation process. I have read about
backsweetening using "concentrate". What are these concentrates? Are they
the frozen juice concentrates I find at my local grocer's frozen foods case
(ie, Welches, etc)? How would one use them? What would be the proportions
of defrosted concentrate to cider? Or is the concentrate some other product?
Thanks
Joe Margevicius
------------------------------
Subject: 2008 Upper Mississippi Mash-Out results are posted
From: "Crist, Jonathan" <Jonathan.Crist@bsci.com>
Date: Mon, 28 Jan 2008 17:39:41 -0600
The 2008 Upper Mississippi Mash-Out is history! The organizing
committee would like to thank our sponsors, our volunteers, our entrants
and our guests for helping make this year's Mash-Out such a HUGE
success! You can check out the results and pictures on our website at:
http://www.mnbrewers.com/mashout
SET YOUR CALENDAR! Next year's Mash-Out will be held on Jan 23-24, 2009!
Jonathan Crist
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End of Cider Digest #1435
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