Religions change; beer and wine remain.
– Harvey Allen
One of the earliest science experiments man stumbled across was the trick of fermentation. Leave out something sugary long enough and eventually it starts to contain ethanol (alcohol). A time consuming process, but one that leaves the user with a very sterile beverage usually devoid of many of the parasites and disease causing agents commonly found in water. As people tinkered with producing various forms and types of alcohol, the ancestors of modern beer began to be consumed. Made primarily from grains such as wheat or barley, beer (and other alcohols) provided the world with a civilization altering drink that both contained medicinal properties and mild altering chemicals.
The earliest evidence for beer in the ancient world is roughly between 3000 and 4000 BCE in Mesopotamia. Ancient hymns and recipes have been found that detail the beverage and cement its status as one of the leading sources of liquid nutrient intake beginning over six thousand years ago. From the point, beer production and consumption spread throughout the world until it reached every point on the globe. Before the modern era, only the Australian aborigines, Eskimos, and peoples of Terra del Fuego lived in societies without alcohol. Often used in religious rites as well as deity mythos, beer was both revered and reviled throughout history as a liquid escape from the realities of one’s mind. At one point it was estimated that over 40% of cereals grown in the Fertile Crescent were used for brewing.
The chemical processes that surround rudimentary brewing are relatively simple; they center on the process of fermentation. Yeasts (or other organisms adapted to anaerobic environments) convert glucose to ethanol and carbon dioxide, gaining energy in the form of adenine triphosphate (ATP) and nicotinamide adenine dinucleotide (NADH) in the process. Exploiting this pathway allowed mankind to control the methods of alcohol production and thereby harness all of the effects that accompany such beverages.
Though ancient peoples did not understand the chemistry behind fermentation (similar to bread making), they did understand that something was causing their starting materials to transform into fermented beverages. Rulers quickly learned that alcohol consumption had to be monitored to maintain a prosperous nation, and the Babylonian king Hammurabi (1792 – 1750 BCE) explicitly mentioned taverns (establishments that served beer) in his law codes in order to ensure “that they operated sensibly.” Though roughly 3750 years since his famous code was established, civilizations continue to regulate and pass laws concerning the production and consumption of alcohol.
Impact of Beer on a Human Culture:
On November 30, 1487 the Duke of Bavaria enacted the Reinheitsgebot law to regulate beer production in the region. According to the new law, beer could only be manufactured using three ingredients: water, barley, and hops. Using only these three ingredients to make beer is impossible – you need yeast to perform the fermentation. However, until Louis Pasteur discovered yeast’s role in fermentation in 19th century, the role of yeast in beer making was unknown. Brewers typically used the sludge at the bottom of one vat as a starter culture for their next batch of beer, and so the microscopic yeast was passed from one brewing to the next. The Reinheitsgebot law was created for economic reasons: wheat and rye (other typical alcoholic starter grains) were required for bakeries, and by limiting brewers to solely using barley it enabled bakers to procure their wheat and rye at reasonable costs. In the centuries since that law was created, German beers became some of the world’s finest. Many German brewers still adhere to the virtues of the Reinheitsgebot, though the law was replaced in the early 1990s with a more modern version that took into account new knowledge of brewing and fermentation. 
 Hornsey, Ian S. Alcohol and Its Role in the Evolution of Human Society. Cambridge, UK: Royal Society of Chemistry, 2012. Page 1.
 Forbes, R. J., Studies in Ancient Technology. E. J. Brill, Leiden, vol. III. 1955.
 Hornsey, Ian S. Alcohol and Its Role in the Evolution of Human Society. Cambridge, UK: Royal Society of Chemistry, 2012. Page 556.
 Roth, M. T., Law Collection from Mesopotamia and Asia Minor. Scholar’s Press, Atlanta, GA, 2nd revised en, 2000.