Newbie problem - fermentation stuck.

Newbie problem - fermentation stuck.

Post by Fred F » Mon, 28 Sep 1998 04:00:00

Hi there everyone!

And before I start... Yes, I have read the FAQ.

I am trying to make 5 gallons of wine from a Boots German White Wine kit -
the one with the wine powder. It was about a year past its sell-by date but
I supposed it would be OK if I used new yeast. I rigorously sterilized the
equipment and had it warming with a heating element at about 26C. Anyway, it
fermented fine for about two weeks and then all but stopped. It was still
very sweet and had a hydrometer reading of about 1030 - a further 2 weeks
past with little change. I then dropped the temp. to about 21C and added a
new yeast batch. Nothing! Dead as a door nail!

Any ideas?





Newbie problem - fermentation stuck.

Post by TomS » Mon, 28 Sep 1998 04:00:00

Fred -

Been there, done that!

I assume that you're fermenting in a glass carboy.  That is sometimes a
problem because of oxygen deprivation in the fermentation.  The yeast needs
at least some access to air to propagate.  Also, it has to have the correct
nutrients available, and prefers to have some solids in the juice.

Stuck fermentations are sometimes very hard to restart.  At 1.030 sp. gr.,
you're at about 8% residual sugar.  That's not as bad as it could be.  (If
you're stuck at 1.5%, you have a really bad problem!)

I'd recommend going to the store and buying a couple of bunches of fresh
grapes, squeezing them for the juice, and making a fresh starter.  Also,
rack the stuck wine with splashing into another container, and add some
diammonium phosphate (About 10 grams should do.).  Be sure to re-hydrate the
yeast before using it by mixing it in warm water (100 deg. F) for a few
minutes.  Don't let it sit around after rehydrating!  Add it (the yeast) to
the fresh juice, which should be at room temperature, within 5 minutes.
Once the starter is going vigorously, mix some of the stuck wine into it.
Not too much at first;  the idea is to get the newly active yeast "used to"
the presence of *** gently.  Let the activity build back up, and add
some more stuck wine.  Incidentally, you don't say what strain of yeast
you're using, but some of them are very sensitive to *** and low
temperatures.  I assume that you want the wine to go dry, so use a vigorous
strain like Montrachet or Chanson.  I don't recommend heating the
fermentation of a white wine, but keep it at or about 20 C.
If you can get actual yeast nutrient, that's even better than diammonium
phosphate (DAP).

Good luck!

Tom S