In the end, brewing has transformed the dry, tasteless barley grain into a bubbly, bitter, acidic liquid (its pH is about 4) that is 90% water, 1 to 6% alcohol, and between 2 and 10% carbohydrates, mainly the long-chain dextrins that provide body.
From the book On Food and Cooking (2nd edition) by Harold McGee. © 2004 Harold McGee.
By permission of Scribner, a division of Simon & Schuster, Inc.