1. General principles of brewery hydrolysis

Unlike wine, cider or fermented fruit-based beverages, beer is a cereal-based beverage whose fermentable sugar content is not defined at the outset. In viticulture, the ripening of grape juice depends on weather conditions, and during the harvest the winemaker transforms the sugars into alcohol, but cannot interfere with the alcoholic strength. The world of brewing is quite different, since the brewer can decide on the balance he gives to his beer by defining the sugar/alcohol ratio himself.

The brewer's first task is to extract fermentable sugars from the starch contained in barley malt. The starch contained in the barley is gradually broken down during mashing (hot maceration of the barley). This transformation corresponds to enzymatic hydrolysis of the starch by the malt's natural enzymes. At harvest, barley contains no enzymes (amylases). The enzymes needed...