Potassium Carbonate is a white salt, soluble in water, which forms a strongly alkaline solution. It can be used to raise the mash ph in brewing and reduce acidity in winemaking. In winemaking 3.4 grams of potassium carbonate per gallon will effectively reduce acidity by 0.1%. In brewing, potassium bicarbonate can be used to raise the mash ph of dark beers like porters and stouts.
Potassium carbonate is a stronger base than the potassium bicarbonate, and can result in more violent chemical reactions.