Campden tablets are potassium metabisulphite in tablet form. Campden tablets for beer and alcohol will prevent wild yeast, bacteria growth, and oxidation in your wash. The convenient tablet form takes the guesswork out of measuring. Each tablet adds 30 ppm free SO2 per gallon (pH dependent). Grind one Campden tablet per gallon into a powder and dissolve in water before adding it to the wash. Each container comes with 110 tablets.