Potassium Metabisulfite 4 oz
Potassium Metabisulfite is a widely used winemaking agent. It effectively kills wild yeast and bacteria. The condition of your grapes and pH levels may vary the amount needed. This agent helps to clear the way for your yeast, better allowing it to do its job by removing all competition. Sulfites also aid in inhibiting enzymatic browning in white wines, and improve the flavor when used correctly. Metabisulfite does lose potency over time, so you should replace your supply at least annually. If you have some old metabisulfite, it can be used for sanitizing purposes.
For Killing Wild Yeast and Bacteria: 1/4 teaspoon per 5 gallons, which yields 50 ppm. Wait 24 hours for Potassium Metabisulfite to dissipate before adding your desired yeast strain.
For Sterilization: Add 1 teaspoon Potassium Metabisulfite and 0.5 teaspoon of Citric Acid and seal the container. Allow 20 minutes for sterilization to complete.