Historic Brewing Process

The basic brewing process did not change in the United States for over one hundred years and can be summarized as a chemical reaction between four ingredients: water, hops, yeast, and starch, most commonly malted grain. After roasting the desired starch, water is added and acts upon the starch. The starch converts into a sugar form, "wort." The wort is boiled for up to two hours, and, in order to manipulate the flavor profile of the mixture, hops are added. More hops leads to a more bitter beer. The principal step is adding yeast. The yeast consumes the sugars in the wort, beginning the fermentation process, which lasts up to four days.

Courtesy of Stanley Wade Baron's Brewed in America: The History of Beer and Ale in the United States