About this Article
Written by: Erik Tolmachoff
Written on: May 3rd, 2003
Tags: chemical engineering, food & drink
Thumbnail by: Vins/SXC
About the Author
During Spring 2003, Erik Tolmachoff was a senior pursuing a Bachelor of Science Degree in Chemical Engineering at USC. He is a member of the American Institute of Chemical Engineers and enjoys studying real life applications of chemical engineering.
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Volume V Issue IV > The Engineering of Beer
Beer has existed for thousands of years. During its long history its popularity has changed considerably in response to technological advancements and social pressures. Although beer was created before the science behind it was understood, the process of making beer can be thought of as a series of chemical engineering tasks that includes separation processes and biochemical reactions. Although chemical engineers work in large breweries, many smaller breweries and microbreweries employ senior beer makers known as brewmasters. While not trained as engineers, brewmasters use much of the same equipment and many of the same skills that chemical engineers employ every day.


It is likely that the processes of malting and fermentation--both essential in beer brewing--were first discovered by accident about 6,000 years ago in the Middle East. It is believed that malted grain was first created when rainwater fell into earthen grain storage jars. After the grain was dried, it was found to be sweeter, and so was used to make bread. When the bread became wet, the soupy mixture of yeast and malt resulted in fermentation. It was not until the nineteenth century, however, that yeast was discovered to cause the fermentation that gives beer its alcoholic content [1].

Beer's Evolution

Despite beer's early origins, most experts today credit 16th century Germany for the beverage as we know it today. German brewers in the 1500s standardized brewing into the five-stage process still in use: malting, mashing, brewing, fermenting, and maturation. The German government was the first to control the content of beer when it passed the German Beer Purity Law, or Reinheitsgebot, in 1516. This law limited beer to four ingredients: water, barley, hops, and yeast. In accordance with the law, beers containing other ingredients were banned from sale in Germany as late as 1987, when the law was overturned.
Carolina Brew
Figure 1: Hops are one of the main and vital components of beer.
Before the passage of the Reinheitsgebot, many German beer makers used rice, maize, sorghum, or other cereals to make a less costly or more distinct beer. Today, many beer makers still use additional ingredients such as sugar to improve taste or alcohol content, or barley to create a less costly product. Nevertheless, many beer makers around the world still advertise that they brew in strict accordance with Reinheitsgebot because of the modern association of beer with German culture.
Even while keeping within the confines of the general five-step brewing process, brewers have been able to create a wide variety of beers. Stout beer, for example, was invented by accident when an error in the malting stage caused the barley to cook too much and gave the beer a darker color and more distinct taste. Because of the long documented history of beer, brewers today have broad options when creating new varieties.
They can malt the beer in different ways; use nontraditional ingredients or different types of yeast; brew and ferment beer at different temperatures for different amounts of time; choose from a wide variety of hops (one type of which is shown in Fig. 1); and age beer at their discretion. The artistic freedom that brewers wield has resulted in a wide variety of beers, including bocks, stouts, and wheat beers, all of which come in different colors with different tastes and varying alcohol content.