Campden tablets (potassium or sodium metabisulphite) are a sulfur based product that is used primarily in wine, cider and beer making to kill certain 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 (i.e., drinking water from municipal sources). Campden tablets allow the brewer to easily measure small quantities of sodium metabisulfite, so it can be used to protect against wild yeast and bacteria without affecting flavor.
