does freezing kill yeast?

does freezing kill yeast?

Post by Ricard » Tue, 18 Sep 2001 11:15:18



I'm making a batch of Muscat now. The grapes (from New Mexico) were picked
at 27 Brix, so this is a sweet wine.

My question:  Does freezing the wine to stop fermentation kill the yeast so
that I won't have to worry about fermentation starting up again later?

I stopped the fermentation by putting the wine in a beer keg (purged with
CO2) and putting the keg in my lager fridge at 24F. I plan to leave the wine
there for at least 2 weeks.

Any advice/suggestions?

Ricardo

 
 
 

does freezing kill yeast?

Post by chris.NO$PAM.verno » Tue, 18 Sep 2001 16:17:52


Ricardo
Generally, freezing does kill yeasts, but the wine may not be completely frozen
at that temperature.  Yeasts die when their cell walls rupture because ice
forms.  The *** (and residual sugar) will depress the freezing point and
protect the yeast.  The following table gives the freezing point of various
*** contents in water (the unfermented sugar will depress this a degree or
two further):
9%          25F
10%        24F
11%        23F
12%        22F

So I'd wonder if your wine was really frozen at all.  Even if it appears icey,
the yeast may only be stunned.  I regularly freeze cupfuls of yeast slurry,
protected with 10% glycerine.  I thaw them out and they're fermenting 2 days
later.

Chris

Quote:

> I'm making a batch of Muscat now. The grapes (from New Mexico) were picked
> at 27 Brix, so this is a sweet wine.

> My question:  Does freezing the wine to stop fermentation kill the yeast so
> that I won't have to worry about fermentation starting up again later?

> I stopped the fermentation by putting the wine in a beer keg (purged with
> CO2) and putting the keg in my lager fridge at 24F. I plan to leave the wine
> there for at least 2 weeks.

> Any advice/suggestions?

> Ricardo


 
 
 

does freezing kill yeast?

Post by Ricard » Wed, 19 Sep 2001 15:07:31


Chris,
Thanks for the informative reply. I turned the temp down to 20F today, but
will assume that the yeast is still alive. It's the K1V strain if that makes
any difference.
Ricardo


Quote:
> Ricardo
> Generally, freezing does kill yeasts, but the wine may not be completely
frozen
> at that temperature.  Yeasts die when their cell walls rupture because ice
> forms.  The *** (and residual sugar) will depress the freezing point
and
> protect the yeast.  The following table gives the freezing point of
various
> *** contents in water (the unfermented sugar will depress this a
degree or
> two further):
> 9%          25F
> 10%        24F
> 11%        23F
> 12%        22F

> So I'd wonder if your wine was really frozen at all.  Even if it appears
icey,
> the yeast may only be stunned.  I regularly freeze cupfuls of yeast
slurry,
> protected with 10% glycerine.  I thaw them out and they're fermenting 2
days
> later.

> Chris


> > I'm making a batch of Muscat now. The grapes (from New Mexico) were
picked
> > at 27 Brix, so this is a sweet wine.

> > My question:  Does freezing the wine to stop fermentation kill the yeast
so
> > that I won't have to worry about fermentation starting up again later?

> > I stopped the fermentation by putting the wine in a beer keg (purged
with
> > CO2) and putting the keg in my lager fridge at 24F. I plan to leave the
wine
> > there for at least 2 weeks.

> > Any advice/suggestions?

> > Ricardo

 
 
 

does freezing kill yeast?

Post by J Reite » Wed, 19 Sep 2001 22:00:35


Ricardo,
   is this the Sauv Blanc you are making? Why are you turning the temp down
so soon? If anything it ought to be settling at the 50-60 degrees F that you
had it fermenting at. Rack and add your bentonite if fermentation has
stopped, let settle. Then, without racking, drop the temp to 28 degrees F
for two-three weeks to cold stabilize. Excess tartaric will fall out of
suspension and pack down the lees some more.
Joanne


Quote:
> Chris,
> Thanks for the informative reply. I turned the temp down to 20F today, but
> will assume that the yeast is still alive. It's the K1V strain if that
makes
> any difference.
> Ricardo


message

> > Ricardo
> > Generally, freezing does kill yeasts, but the wine may not be completely
> frozen
> > at that temperature.  Yeasts die when their cell walls rupture because
ice
> > forms.  The *** (and residual sugar) will depress the freezing point
> and
> > protect the yeast.  The following table gives the freezing point of
> various
> > *** contents in water (the unfermented sugar will depress this a
> degree or
> > two further):
> > 9%          25F
> > 10%        24F
> > 11%        23F
> > 12%        22F

> > So I'd wonder if your wine was really frozen at all.  Even if it appears
> icey,
> > the yeast may only be stunned.  I regularly freeze cupfuls of yeast
> slurry,
> > protected with 10% glycerine.  I thaw them out and they're fermenting 2
> days
> > later.

> > Chris


> > > I'm making a batch of Muscat now. The grapes (from New Mexico) were
> picked
> > > at 27 Brix, so this is a sweet wine.

> > > My question:  Does freezing the wine to stop fermentation kill the
yeast
> so
> > > that I won't have to worry about fermentation starting up again later?

> > > I stopped the fermentation by putting the wine in a beer keg (purged
> with
> > > CO2) and putting the keg in my lager fridge at 24F. I plan to leave
the
> wine
> > > there for at least 2 weeks.

> > > Any advice/suggestions?

> > > Ricardo