Potassium bisulfate is a chemical compound of the formula KHSO4. This compound is commonly used in the conversion of tartrates to bitartrates in wine. Potassium bisulfate is also used as a disintegrating agent in analytical chemistry. A solution of potassium bisulfate behaves like if the two congeners (K2SO4 and H2SO4) were side by side uncombined. Adding ethanol to a solution of potassium bisulfate precipitates out sulfate.