Potassium metabisulfite is a common wine or must additive, in which it forms sulfur dioxide gas (SO2). This both inhibits the growth of most wild microorganisms, as well as acts as an antioxidant, protecting both color and flavors of wine.
The typical dosage is 1/4 tsp potassium metabisulfite per 5 gallons of juice/must (yielding approximately 75 ppm of SO2) prior to fermentation;
At bottling, approximately 150ppm SO2 for whites, and no more than 200ppm for reds should be your final SO2 value at time of bottling.
8oz
MSDS Sheet
