Sluggish Fermentations — Cabernet Franc
Stan Sowinski — Falls, Pennsylvania asks,
I’ve got a reoccurring problem with my estate red wines. For the past two years my Cabernet Franc fermentations have been stalling out when the specific gravity (S.G.) hits 1.000. Malolactic (ML) culture is added at this point and it does complete within a few weeks. Fearing spoilage problems, I added SO2 shortly after ML completion (based on pH using WineMaker’s sulfite calculator.) I started with an initial S.G. of 1.023, pH of 3.41 and titratable acidity of 6.4. I used D-254 with a properly prepared yeast starter and the maximum recommended amount of DAP and yeast nutrient, and fermented between 65-75 °F (18-24 °C). Secondly, It has been two months since the primary fermentation. Is it too late to re-ferment this batch of 35 gallons (132 L) of Cabernet Franc? What are the possible consequences of adding new yeast and nutrients at this point? It has been racked one time and has minimal lees.