The introduction of added fermentable materials in order to enhance carbonation and give a head to the beer. Beer would be flat without it. All brewing equipment should be throughly cleaned beforehand with either bleach or antibacterial cleanser. By testing a beer's specific gravity it is possible to determine when the beer is done fermenting and to know in advance how strong the beer will be. Rinsing grains to extract residual sugar that clings to the grains after they have been mashed.
Warm water is poured over the grains and hops above a strainer.
Beer is about 90 percent water, so water is an important ingredient. Tap water is usually acceptable for use in beermaking although it is recommended that a filter be used to remove chlorine. Nondistilled spring water can also be used. Discernible off-flavors in the water may give the beer a harsh taste. The sweet, concentrated sugar solution produced by boiling hops and malt.