Campden Tablets are easy-to-use capsules of potassium metabisulfite to be used to prevent oxidation and growth of wild yeast and bacteria in wine must. One tablet in one gallon of must yields 75 ppm total sulfur dioxide. Crush into a powder before using. Some beer brewers also use campden tablets to remove chlorine or chloramine from their brewing water. (50 count pictured. this price is for a 100 count satchel.