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From: rcd@nbires.UUCP (Dick Dunn)
Newsgroups: net.cooks
Subject: Re: (Hard) apple cider (and vinegar and how it all works)
Message-ID: <129@nbires.UUCP>
Date: Tue, 15-Oct-85 04:23:20 EDT
Article-I.D.: nbires.129
Posted: Tue Oct 15 04:23:20 1985
Date-Received: Sat, 19-Oct-85 06:34:30 EDT
References: <251@ssc-vax.UUCP> <644@bbncc5.UUCP>
Organization: NBI,Inc, Boulder CO
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> >Hard apple cider is nice but any cider that sat around in our house
> >always went to vinegar, not some semi-alcoholic beverage?  Any tips
> >on how to get this reaction to happen properly.
> 
>  Friends of mine claim to have prevented this by periodically feeding some
> sugar to the little beasties doing the fermentation (i.e. by adding sugar to
> the cider once a week).

This isn't really what it takes.  The sugar will keep it fermenting (until
the alcohol eventually kills the yeast) but it won't prevent vinegar.
Here's the picture:

The apple juice has fermentable sugars in it.  If it's just been pressed
and hasn't been pasteurized, it will also have wild yeast in it (from the
air, on the fruit, etc.)  If you just set it aside and don't let it get too
cold, the yeast will go to work and ferment the sugars to alcohol.  If it
was pasteurized, you can leave it open to the air (as some folks have
suggested) and it will acquire yeast of some sort and start working.  You
can also throw in a package of yeast intended for making beer or wine.  The
sort of yeast you use (or catch in the air) can make a fair difference in
the flavor of the result, as all homebrewers and winemakers know.

Vinegar is created by a bacterium (acetobacter) which consumes alcohol and
produces vinegar.  Once you start fermentation, your cider is susceptible
to acetobacter.  It will pretty much keep up with the yeast, and there's no
reasonable way to get rid of acetobacter without killing the yeast.  What
makes the difference is whether you've got enough acetobacter in the air in
your house to get into the cider.  One thing is pretty sure--once you spoil
a batch of cider into vinegar, you WILL have plenty of acetobacter around
the house in the air; at that point, everything you try to ferment in an
open container will pretty dependably turn to vinegar.  Despair not; you
need not turn to a permanent diet of salads plus fish&chips.

The solution:  Two things--first, get some good yeast to start things
going.  Either beer or wine yeast will work, tho wine yeast will hang on
better at higher alcohol.  I don't know right off how much sugar is in
apple juice--would someone who has some juice and a hydrometer please go
home and measure it and post the result?  (If it's more than about 1.080
SG, it suggests a wine yeast.)  If you're attempting to produce more than
about 8% alcohol by volume during fermentation, go with a wine yeast. 
(I'd use a champagne yeast.)
Second thing--give up the open fermentation.  Use a CLEAN plastic pail
covered with a sheet of plastic or a CLEAN glass jug with a fermentation
lock (a little gozouta/no-gozinta gadget for brewing and winemaking) so
that the only critters munching on the apple juice are the yeast you used.
[PLEASE don't try fermentation in a sealed bottle--yeast produce lots of
carbon dioxide during fermentation and the process isn't much slowed by
pressure.  You can explode a bottle very forcefully.]

This is kind of a simplistic explanation, but it will dodge the problems of
vinegar and the worst of the off-tastes.
-- 
Dick Dunn	{hao,ucbvax,allegra}!nbires!rcd		(303)444-5710 x3086
   ...Simpler is better.