Contains papain to prevent chill haze. Water hardener. Many English commercial breweries use Burton Water Salts to harden the water, which helps Irish Moss work better to coagulate haze-producing malt proteins, and the harder water also helps provide a crisper hop character. The magnesium provides a vigorous fermentation, and the salt adds an illusion of body to the finished beer. Use 1 to 4 teaspoons per 5 gallons. If you are doing partial or all grain brewing, add at the start of the mash, or add at the start of the boil for extract brews.