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Cider Digest #0939
Subject: Cider Digest #939, 20 December 2001
From: cider-request@talisman.com
Cider Digest #939 20 December 2001
Forum for Discussion of Cider Issues
Dick Dunn, Digest Janitor
Contents:
Chemistry Answers (Andrew Lea)
(no subject) (Sbmwood65@aol.com)
Re: Cider Digest #938, 15 December 2001 (Dan Spoelstra)
cider distillation (Bob and Winnie)
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Subject: Chemistry Answers
From: Andrew Lea <andrew_lea@compuserve.com>
Date: Sun, 16 Dec 2001 09:50:50 +0000
At the risk of being considered a total nerd, I'm going to lump the
answers to a few chemical queries from the last Digest all together
here, if I may. Nobody is forced to read it!!:
> Anyhow, it may be possible (in addition to malolactic fermentation) to
> reduce acidity to some extent by chilling a cider to near freezing to
> precipitate some of the acids present in the cider.
Sorry, no. The reason it works in (grape) wine is because potassium
tartrate (not the free tartaric acid) is insoluble in the cold, is
usually supersaturated at the end of fermentation, and will shock out
readily if chilled. None of this applies in cider where malic is the
chief acid. In fact, tartaric acid is only found in grapes and nowhere
else among common fruits - so grape wines are unique in this behaviour.
Most other fruit wines contain malic or citric as their chief acids.
Freezing to reduce the acid will not work for them.
> Wouldn't the conversion of malic acid to lactic acid leave the pH about
> the same?
>
No. The acidity drops as much as a half during MLF because malic is a
dibasic acid (two replaceable hydrogens per molecule) while lactic is
monobasic. The extra carboxylic acid group is metabolised away as
carbon dioxide and goes up the spout (hence the bubbles during MLF).
The pH (being a non-linear function) also rises typically by about 0.5
units to reflect this. Titratable acid gives a roughly linear plot with
perceived acidity and is a much more useful measurement for this purpose
than pH.
Incidentally I recently did some regressions on the relationship betwen
pH and acidity in cider apple juices, using a statistical software
package and some empirical data of my own. These were the 'best fits':
Y = 64.56*exp(-1.384*X) (exponential)
or
Y = 0.4528*X^2 -4.097*X + 9.3632 (binomial)
where Y is titratable acid in % malic and X is pH.
> In aging what role does the slow esterification of ethanol and malic or
> lactic acid to ehtyl maleate or ethyl lactate play? That would reduce
> the acidity and increase the complexity of the smell. What do ethyl
> maleate and ethyl lactate smell like?
>
Yes the esters ethyl lactate and ethyl malate are indeed formed on
ageing (note spelling - malic and maleic acid are different things and
there's no maleic in apple). If you look at a GC/MS (gas chromatography
/ mass spectrometry) analysis of cider you will probably see them. They
both have fruity estery odours, and ethyl lactate in particular has
sometimes been used as a 'wine improver'! Their concentrations are only
at the parts per million level. Hence they may make a positive sensory
contribution to an aged cider (remember Julian's remark about more
complex flavours following MLF - this is one reason why). But at such
low levels they make no significant contribution to reducing acidity.
The reason for this is that the chemical equilibrium for ester formation
in dilute aqueous acid and ethanol lies far to the 'left hand side' -
i.e the esters are hydrolysed back to their parents almost as quickly as
they're formed.
Andrew Lea
nr Oxford UK
- ----------------------------------
Visit the Wittenham Hill Cider Page at
http://www.cider.org.uk OR
http://ourworld.compuserve.com/homepages/andrew_lea
------------------------------
Subject: (no subject)
From: Sbmwood65@aol.com
Date: Tue, 18 Dec 2001 21:17:38 EST
As a beginner in Cider and Mead making I was wondering if anyone had any
instructions/hints on making Perry? I've helped make several batches of
Cider and Cyser along with a couple of rasberry meads but would like to try
making something with pears. I can not even find a good source of pear
juice. Have only found "Jumex" brand from Mexico made from pear puree,
sugar, citric acid and ascorbic acid. Would this be any good to try?
Steve Mattheeussen
Greenville, WI
------------------------------
Subject: Re: Cider Digest #938, 15 December 2001
From: Dan Spoelstra <ssphoto@iserv.net>
Date: Wed, 19 Dec 2001 10:22:43 -0500
Hi I'm Dan, (new Cider Digest reader and enjoying it very much)
I've learned a lot the past few weeks following the interesting dialog
regarding "too tart" cider and the differences in yeast.
I've been making sweet (unfermented) cider for several years from my
homegrown apples(I have 1- tree each of 20 varieties). My cider this year
was way too sweet-mostly Spigold(fantastic flavor),Hawaii(sweet),King
David(tart),a few Cox & Hudson's golden gem(sweet). Next year I hope to
add a few early ripening varieties like Duchess(tart) and Dolgo crab
(high tannin?).
Can't I press these early varieties and freeze the juice to mix with
the apples to be pressed in November? I'm hoping this will give me
better sweet cider and also a better blend for my first attempt at HARD CIDER.
NOW MY REAL QUESTION: I have room for 2 more trees. I'd like to plant a
couple of true cider varieties. I'm sure I have a good base but am
confused about what else I may need-- Bittersweets, Sharps ?? Please
make suggestions. Or is this really not that important to making good
cider. I don't want the tart stuff you all have been talking about Or is
the-"too tart" problem unrelated to apple varieties and only a matter of
the fermentation process?
sorry if this is too long
THANKS for reviving my interest in cider!
Dan Spoelstra
ssphoto@iserv.net
www.opma.com/spoelstra
------------------------------
Subject: cider distillation
From: Bob and Winnie <natvwine@cut.net>
Date: Wed, 19 Dec 2001 21:46:14 -0700
> It's true that freezing cider will concentrate both alcohol and aldehydes;
in my experience
>
> not worth it. I have however, had extensive experience distilling cider,
perry, apple wine
>
and pear wine as well as many other wines (as a bonded winery we are
allowed to do this for testing purposes) and can say that a properly
aged product will contain much less undesireable components and can
usually be distilled without worry as to "heads and tails". With a
little practice, a product vastly superior to most of those on the mass
market can be made at home using simple equipment. Don't be intimidated
by industrial technology!
> volumes that are discarded and the back-blending are the "art" of the brandy
> making process (this is incorrect usage as brandy is made from wine and has
> legal definition).
>
> This is all hypothetical of course since I've never ever ever concentrated the
> alcohol in a naturally fermented material.
>
>
> - --
> John A. Ray
> Research Associate-Floriculture
> Colorado State University
> Department of Horticulture & Landscape Architecture
>
------------------------------
End of Cider Digest #939
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