Welch's batch too sweet...question

[g1230g]

Greetings all....I have two separate questions - both involving re-fermentation.

Regarding a concord grape batch - if a batch turns out a bit too sweet for my taste - I want to ensure that I understand the re-fermentation process.

My original yeast (premier curvee) has a maximum tolerance of 16%. Am I correct in assuming that if I re-ferment with a champagne yeast with an 18% tolerance - in theory the re-ferment would burn up some of the remaining sugar - until the yeast dies out - resulting in a bit dryer of finished product. Does this sound logical?

The resulting ABV is not really a concern.

The second question is stuck fermentation - would the re-fermentation process apply to stuck fermentation? Any tips on re-fermentation are appreciated.

My questions are mostly for learning and experimentation.

Thanks in advance!

 

[DoctorCAD]

If you had started with the champagin yeast, maybe it would go to 18% or maybe not. Adding it now, it most probably will not even start.

Those numbers on the pack are guidelines and not guaranteed.

 

[bernardsmith]

Hiya g1230g - and welcome. You need to take a step back and think why a fermentation has stalled. If the problem is something fundamental about the nature of the fermenting liquid then you may not be able to restart the fermentation until you resolve the issue but in any event the best way to restart a stalled fermentation is not to add more or different yeast. The best way is to add small amounts of the problem liquid to an actively fermenting "starter". In other words, you might take your champagne yeast and pitch that in a cup of say, sorbate free apple juice.
When this cup is very actively fermenting you then add 1 cup of your stalled wine must. When these 2 cups are actively fermenting, you add 2 cups from the stalled must. When those 4 cups are actively fermenting you add four cups from the stalled liquid and so on until the entire batch of stalled liquid is now actively fermenting.

What you need to monitor is whether the cups you add are actively fermenting. If they fail to ferment then you need to stop because there is a problem not with the yeast but with the must - the pH may be too low, there may be too little nutrient in the must, all the fermentable sugars may have been consumed

 

[g1230g]

Thanks for the input guys - I appreciate the feedback!