+3 Gypsum 2oz 400000000701 $1.99 In stock Quantity: 1 Add to Bag Product Details Gypsum adds hardness to soft brewing water. Brewers that use distilled water like to add some gypsum back into the water to give it some hardness. Gypsum can also be used to lower the pH of water. Use 1 teaspoon per 5 gallons. Save this product for later Favorite