Calcium Carbonate The Malt Shop Sale! from 38000 /per Qty. Add to Cart This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. Also known as "chalk". Sometimes used for temporary hardness in dark beers. Adjusts pH up. In winemaking: Used to lower acidity levels. 50g package SKU:WM20 brewing salts dark beer hardness increase pH other water mineral