The Use of Hops in Brewing...

Only a few ingredients are needed to make beer. Most beers are brewed from barley malt, unmalted grain such as corn or rice, hops, yeast, and water. The brewing value of hops is found in the unique flavors and other properties which come from resins and oils inside the lupulin glands.
 
Barley malt is ground and mixed with other grains to “fuel” the fermentation process. These ingredients are mixed with water and “mashed” so that the grain starches are converted to smaller carbohydrates, mostly fermentable sugars. This “mash” is separated into a clear liquid called “wort” which contains the sugars and other grain-derived components, and the non-soluble “spent grains”.
 
The wort and hops are boiled in the brew kettle to extract the hop resins and oils. The boiled out “spent hops” are usually added to the “spent grain” and sold as high quality livestock feed. The wort is clarified and cooled, and yeast is added. After several weeks of fermentation and final clarification, beer is produced.