Calcium Sulfate is a critical component in the measurement of permanent water hardness (also known as non-carbonate hardness). This part of water hardness is defined by the sum of all calcium and magnesium ions that are associated with anions such as chloride or sulfate. It is referred to as permanent hardness because of the fact that it will not precipitate under the influence of heat. Therefore, calcium sulfate is also one of the primary salts used for the improvement of calcium levels in beer. Proper calcium levels in beer can provide the following influences that are generally considered to be positive: they lower the pH, preserve mash enzymes, increase extract yield, improve yeast growth and flocculation, accelerate oxalate removal, and reduce color.
The sulfate ion in this compound is generally thought to promote a drier, more bitter beer. Burton-on-Trent, England is the classic source of water with a high calcium sulfate content, caused by the region’s large gypsum deposits. The emulation of this classic water has led to the term “Burtonization,” meaning to improve one’s brewing water via the addition of calcium sulfate. This water treatment is common for the production of pale ales and India pale ales.