Potassium Sorbate

Potassium sorbate is a wine stabilizer that prevents renewed fermentation after sweetening as well as vinegar formation.  Best used in combination with Potassium Metabisulfite.  Produces sorbic acid when added to wine.  When active fermentation has ceased and the wine is racked for the final time after clearing, potassium sorbate will render any surviving yeast incapable of multiplying.  When wine is sweetened before bottling, potassium sorbate is used to prevent re-fermentation when used in conjunction with potassium metabisulfite. 

Note: Potassium Sorbate will not stop an active fermentation.