Tips on icewine

[drainsurgeon]

I agree with you Treeman, that the ferment will stop because of alcohol poisoning if there is enough sugar in the must (high brix). My original point (in post 11) was that lowering the temp below the range of the yeast will probably "stall" the ferment BEFORE it is complete, not from alcohol poisoning. It WILL start again (maybe in bottles). Your statement: (Sorbate does more than just stopping reproduction. It effectively shuts down metabolism so the yeast can not use the residual sugar) is not correct. Read the article from EC Kraus. Ed clearly states that there is no practical way to successfully stop a fermentation as you were suggesting in post #18 and 20.

I just don't want vintner's out there thinking that they can throw in some kmeta and sorbate to stop a fermentation. They will be making potential bottle bombs. Wait for the ferment to finish, be it from running out of sugar or from high alcohol, it doesn't matter. Then sulfite and sorbate and back sweeten if desired.

 

[Treeman]

I think we do agree on best practices for making a back sweetened wine. I also don't want folks using Sorbate the wrong way, but the EC Kraus info is a broad generalization about how Sorbate works for wine yeast. I'm not trying to stir the pot here, just sharing info. There are many articles about the biochemical effects of Sorbate on yeast. Here is one on metabolism changes. https://www.ncbi.nlm.nih.gov/pubmed/8386922

It is likely these metabolic changes and other enzyme inhibitions that result in a loss of yeast reproduction.