Calcium Carbonate is primarily used in the alcohol industry to increase the pH of fermentations (makes is less acidic). It should be used in higher concentrations compared to potassium carbonate (almost double the amount should be added). Note that your fermentation might turn milky, but it will not alter the taste of your product.
Calcium carbonate has a slow reactive time which means the pH will only change after a few hours. Do not add more than 5g/L at a time.
NOTE: Calcium Carbonate should be dissolved in a small amount of hot water before adding it into your fermentation.