"Art Schubert" <na> wrote in message
...
> Sounds definitive. Thanks. I'll file it away for reference.
>
> I'm still curious about whether a yeast with modest alcohol tolerance
> can possibly do any damage if bottled at or near its alcohol limit
> with residual sugar but without filtration.
>

Another point of view. Get a copy of C.J.J. Berry's book. You will
find that he made *lots* of sweet wines and used neither chemical
stabilizers (ie Sorbate) nor sterile filtration. (yes they were stabile
in the bottle) For many years his writings were considered definitive
by those who made "country" wines. Hard to argue with success.

He did so by running the ferments until the yeast reached it's AT
(Alcohol Toxicity point). The alcohol then acts as a poison and
kills the yeast leaving any remaining sugars as "residual". In fact,
until the advent of chemical stabilizers and sterile filtration, this was
the most commonly used method of producing sweet wines.
(Fortifying to raise the alcohol level above the AT was the other
"common" method)

It worked then and it still does. I routinely make several of these
"old fashioned" (residual sugar) ferments each year. And, if you go
to Jack's site you will find that many of the "old" recipes there are
designed to be this kind of ferment.

Of course, you must always be on guard for anything "strange" that
may get into your wine and be prepared to deal with it. But this is
no different than any other wine.

Let me add a copy of a previous post which you may find helpful:

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"Jeff Griffith" > wrote in message
...
> With regard to method #1:
>
> I've been reading in other postings that the yeast dies off when the
alcohol level
> reaches a certain point (about 12% or so?). If the juice starts out
naturally very sweet
> (no sweeteners added!), is it possible that the yeast will die without
fermenting all
> of the sugar to alcohol? Will other factors reduce the residual level
further?
>
> Thanks,
> Jeff Griffith

Jeff

When (or if) a ferment will "end" (die off) depends on which yeast
strain is used and how much sugar is in the must. It is really quite
simple to determine this when planning a ferment. First, go to:
http://winemakermag.com/referencegui...tstrainschart/
Print this if you can. Note the "Alcohol Tolerance" (AT) column.
This tells you how high each type of yeast can go.

Second, Get a decent (full range) Sugar/SG chart with a PA column.

Third, (example) Take an SG reading of the must. Look at the PA
column on the SG/Sugar chart for that reading.

Next, compare the PA to the AT of the yeast you have elected to
use. If the PA is *less* than the AT, you will end up with a dry wine
with alcohol equal to that PA. BUT - if the PA is *greater* than
the AT, the ferment will "end" (die off) with alcohol equal to the AT
and there will be "residual" sugar left in the wine. Just how much
sugar will remain can be determined by locating the AT *number*
in the PA column of the SG/Sugar chart. The *difference* between
this number and the PA of the must will tell you how much sugar will
remain.

Of course, there are a myriad of variables, but this method will give
you very good "working" estimates for planning your ferments. This
is especially important when doing "old fashioned" (residual sugar)
ferments because it allows you to balance residual sugar levels against
the somewhat elevated alcohol levels encountered when doing such
ferments. HTH

FWIW - If you are going to do "old" recipes, you will be best served
by selecting yeasts with ATs in the 13-14% range.

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HTMS