Campden tablets are a sulfur based product that is used primarily in wine and cider making to kill certain bacteria and to inhibit the growth of wild yeast. In wine and cider, campden tablets are used in a ratio of 1 tablet per gallon of must.
Campden tablets can also be used to eliminate both chlorine and chloramines from municipal drinking water prior to making beer. One tablet treats twenty Gallons. Crush before adding to water to aid in desolving.