The choice of grain determines the flavor, body, and color of the final product. The germinated grain, which forms inside the husk, is called malt. This material is dried in a special oven, called a kiln, and is then cracked, liberating the malt from the husk. The malt and the husks are then mashed in a mash tank or tun. Unmalted cereal grains such as rice, corn, wheat flour, or some form of barley are sometimes added to the malt in order to change the various qualities of the beer.
Heated water is added so that the starches are converted to fermentable sugars.
A high water temperature at this point produces a beer with less alcohol but more flavor. In a process called lautering, the mash is then filtered into a brew kettle, and the liquid is called the wort. Hops are boiled with the wort to give the liquid a bitterness, aroma, and color not provided by the cereals or fermentation process. Hops also act somewhat as a preservative. The hop cones are removed after the boiling process and are used in making fertilizer.