How Beer Is Made

Rafters Grille and Brewery, 812 Fourth St, San Rafael, California

Barley, and other grains like wheat, is malted, which is the process of soaking, drying, and roasting grain to activate enzymes in the grain which break down starches into sugars. Roasting malts at different temperatures and lengths of time produces different colors and flavors. By varying the proportions of different malts, the spectrum of colors and flavors are created. Malted grains provide most of the color and sweetness for the beer.

The malted grain is milled to break apart the husk and combined with hot water in the mash tun. The mash is held at 148-156˚ for at least 30 minutes. During this time, enzymes break down starches in the grain into sugars. The sweet colored liquid, called wort, is transferred to the kettle, where it boils for at least one hour.

During the boil, hops are added at different intervals. Hops are a vine flower with bitter alpha acids which impart bitterness and various herbal, citrus, and spicy flavors and aromas to the beer. Most hop cones are crushed and pressed into pellets for easier storage. Hops may also be added during fermentation, called dry hopping, to provide more hop flavor.

After boiling, the wort is cooled down and pumped into a fermenter. Yeast, which is a single-celled fungus, consumes the sugar and creates alcohol and CO². Ale yeast ferments at 70˚ and lager yeast ferments at 50˚. After ermentation, the yeast settles out and the beer may be fined, filtered, or carbonated to create a finished product. The beer is transferred to a conditioning tank prior to packaging or serving directly to the taps.