Campden Tablets are easy-to-use capsules of potassium metabisulfite to be used to prevent oxidation and growth of wild yeast and bacteria in must.
One tablet per gallon equals 30 ppm free SO2. Each tablet is about 0.5g.
Crush into a powder before using. Some beer brewers also use campden tablets to remove chlorine or chloramine from their brewing water with a dosage of 1 tablet per 20 gallons.
1 ounce is approximately 50 tablets.