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Cider Digest #1434
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Subject: Cider Digest #1434, 24 January 2008
From: cider-request@talisman.com
Cider Digest #1434 24 January 2008
Forum for Discussion of Cider Issues
Dick Dunn, Digest Janitor
Contents:
N, Fermentation Speed and Fruit Age (Claude Jolicoeur)
Empty bottle preparation question (Roy Bailey)
rootstock shortage? (esp Geneva) (Dick Dunn)
Judging final cider quality by tasting fruit (Scott Smith)
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Subject: N, Fermentation Speed and Fruit Age
From: Claude Jolicoeur <cjoli@gmc.ulaval.ca>
Date: Sun, 20 Jan 2008 17:01:36 -0500
This discussion on N is getting interesting (although maybe a bit
technical...)
In my effort to understand things a little better, I have taken a look at
my references in oenology and fermentation chemistry... I have seen there a
lot of relatively complex chemical reactions involving C, O, H essentially,
and some P, but nothing involving N!
Andrew writes in his site (http://www.cider.org.uk/nitro.htm):
>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?
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?
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.
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!
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.
Claude Jolicoeur
Quebec
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Subject: Empty bottle preparation question
From: Roy Bailey <enquiries@lambournvalleycider.co.uk>
Date: Mon, 21 Jan 2008 10:23:14 +0000
In message , Jaime Schier <jschier@harpoonbrewery.com> writes
>We are using neither pasteurization nor sulfites to stop metabolic
>activity in bottled cider, relying on sterile filtration instead to
>remove yeast prior to packaging. If there are any other cider makers
>that do the same, would you mind commenting on your technique for
>preparing empty bottles for filling? Our past experience with beer
>indicates that low #'s of environmental (ubiquitous) bacteria and
>generic molds are to be expected in empty bottles, but since beer is a
>nutrient-depleted environment they don't cause much trouble. We rinse
>beer bottles with sterilized, de-oxygenated water which removes nearly,
>but not all, microorganisms from inside empty bottles. Since cider has
>a fair amount of fermentable sugars and other nutrients I'm wondering if
>we need to step up our bottle preparation technique to eliminate them.
>Is anyone rinsing bottles with a sanitizer prior to filling them? We're
>using brand new, single-pass non returnable bottles, so cleaning isn't
>really the issue.
>
My method is to fill the clean bottles with a strong solution of sodium
metabisulphite and stand them for half an hour or so. Then empty and
stand them to drain for (say) 10 - 15 minutes before filling.
This effectively sterilises the bottle and the very small amount of
sodium metabisulphite left in it can do no harm to the product.
- --
Roy Bailey - Proprietor
The Lambourn Valley Cider Company
(Real cider from the Royal County)
<www.lambournvalleycider.co.uk>
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Subject: rootstock shortage? (esp Geneva)
From: Dick Dunn <rcd@talisman.com>
Date: Wed, 23 Jan 2008 13:07:08 -0700
I procrastinated ordering rootstock for this spring and I'm regretting it,
except I wonder if it would have mattered!
Apple rootstocks seem to be in rather short supply most places I've looked.
The most common ones can be found but there are limitations on quantity
and/or caliper.
In the case of the Geneva rootstocks (G.16, G.30 in particular), however,
they're not to be found at all. One large supplier (Treco) told me they're
sold out not only for 2008 but for 2009 as well!
Googling around, it's ironic: There's no end of articles and research
praising the merits of the Geneva rootstocks...but nobody has them for
sale! How did we get into this situation? I've got trees on G.30 from
five years ago! How can it be that we still have a dire shortage of that
rootstock?
- --
Dick Dunn rcd@talisman.com Hygiene, Colorado USA
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Subject: Judging final cider quality by tasting fruit
From: Scott Smith <scott@cs.jhu.edu>
Date: Thu, 24 Jan 2008 09:48:04 -0500
I had this great idea a few years ago that I would plant 40 different
varieties of European cider apples to "pick the best ones" and to
topwork all the trees to 3-4 varieties total. Also the idea is to
find 3-4 which are ripening approximately at the same time and with a
good combination of sweet, sour, and tannins so I can make one big
batch all together. The merits of this approach aside, I now have
trees starting to fruit. I have been tasting the well-ripened apples
to gauge cider interest and I am of the perhaps naive opinion that it
is possible, in particular because my goal is a highly flavored cider
and I don't see how a flavorless apple is going to make a highly
flavored cider. The acidity, tannins, and sugars can also be gauged
by this means. I am finding several varieties have not much
interesting flavor at all in my Maryland climate - they are tasting
like bland sweets. Porter's Perfection is one such example. I have
been very impressed with the flavor of my Frequin Rouge trees: they
are highly flavored, good sweet/sour balance, and with a nice little
tannin kick.
Anyway, my question is for those of you with experience both tasting
fruit and the cider from that fruit, how would you characterize the
relationship? Can you ever take a bland-tasting apple and get a
highly flavored cider for example? Also, since I am tasting no acid
or tannins in my Porter's Perfection, I assume that means my climate
has baked them all out? I am pretty sure I have the right variety
because I am getting those occasional fused fruits which it is known
for.
Scott
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End of Cider Digest #1434
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