Chapter 2

Barley Malts

(book excerpts)

Barley malt is to beer as grapes are to beer. It is ideally suited to brewing for many reasons. Malt is largely made up of carbohydrates, which are composed of starch, sugars, insoluble cellulose, and soluble hemicellulose. Starch, the most important constituent, accounts for about 60 to 65 percent of the malt’s weight, is composed of amylose, which is reduced to maltose and maltotriose and amylopectins that decompose into glucose. Glucose, a monosaccharide, accounts for about 1 to 2 percent of the total starch found in a barley kernel. Cellulose constituents do not contribute to fermentable extract or desirable flavors in the malt. Hemicellulose is a constituent of the endosperm cell walls, which consist largely of beta-glucan. In addition to carbohydrates, malt is made up of proteins and contains vitamins, principally those of the vitamin B complex. Other significant malt constituents include polyphenols, phosphates, lipids, and fatty acids, as well as silica and trace minerals. Polyphenols are acidic precursors of tannins and give beer a bitter and astringent taste. Phosphatases or phytases are major factors in the acidification of the mash. Fatty acids are essential in the yeast cell as reserves, but in excess they reduce the foam’s stability and result in stale flavors in beer—“cardboardy,” “goaty,” and “soapy.”

Click on the following topics for more information on barley malts.

Topics Within This Chapter: