On Jan 26, 6:39*am, Lee wrote:
I'm embarrassed to be asking this question, because I'm a fairly
experienced winemaker. *My question concerns a persistent primary
fermentation, but the SG is not dropping.

A couple of months ago, I received a batch of botrytized juice with a
brix level of 35. *I'm trying to ferment it to the point that the
yeast dies, and I'll be left with some residual sugar. *My problem is
that it keeps bubbling away (vigorously), but the SG hasn't dropped at
all in the last 3 weeks. *It's stuck at 1.026.

I've put in a lot of lysozyme, because I don't want MLF. *Also, the
bubbles "look like" a primary fermentation. *There's been a bit of
temperature change (I warmed it up a bit up to about 76 degrees)
because I wanted to speed things up, but I can't imagine that this is
all CO2 coming out of solution.

The yeast that I originally used died when the SG was still in the
1.050 range. *That left me with too much residual sugar, so I re-
inoculated with Premier Cuvee, which has an alcoholic tolerance of 18
percent. *I realize that the Premier Cuvee might ferment all the way
down to 0, but that's ok...I can always add back some sugar and be
left with a very potent wine. *At this point, I just want things to
stop.

My alternative is to chill the wine, stop the fermentation, then
filter and hit it with sorbate...but frankly, my filtration is never
COMPLETELY sterile, and I don't like sorbate.

Any thoughts? *This is baffling me. *I can understand that the yeast
is still doing it's thing. *I just don't understand why the SG isn't
dropping.

Lee

Lee:

I had some wines in the past that stalled like this, the airlock was
popping regularly at the rate of 8-12 bubbles a minute but the s.g.
drop was only about 0.001-0.002 in a month (I have a narrow range
hydrometer so can see very small drops in s.g fairly precisely). I
think what happened in those cases was the yeast population died down
a lot towards the end of the ferment for various reasons (lack of
nutrients, low temp) but not completely, so the ferment kept going. So
I would suspect just a very slow ongoing ferment in your case.

As others said, ML could also be an option so if you don't mind doing
the chromatography test, that'd narrow down the possibilities.

What style are you trying to make? It sounds like "Sauternes", in
which case you've got already more than enough alcohol in the wine and
the sugar should be on the low side, so why not just stop it now? If
you don't like sorbate (I don't either), use benzoate instead - there
was a recent thread on this. It might be ok to not add anything in the
end, if you filter the wine, th eyeast doesn't seem to be doing much
now so chances are it won't get going again once you clarify the wine.

Pp