This potassium metabisulphite is a sulfur-based product that is used primarily to sterilize wine, cider and in beverage making to kill bacteria and to inhibit the growth of most wild yeast.
This product is also used to eliminate both free chlorine and the more stable form, chloramine, from water solutions (e.g., drinking water from municipal sources).
Available in convenient tablets (1 tablet per gallon equals 30 ppm free SO2 recommended dosage is 1-2 tablets per gallon) or as powder (1/4 - 1/2 teaspoon per gallon).