How Drinking Beer Is in Our DNA: An Interview with Jessica Zinskie

An interest in the pharmacological nature of food led Jessica Zinskie, a postdoctoral researcher at Rowan University, to study the genetics of yeast and the evolution of beer.

By Zack Pelta-Heller | June 30, 2017

Jessica Zinskie, a postdoctoral researcher at Rowan University, has something in common with our exhibition Things Fall Apart: they both focus on the science of decay. An interest in the pharmacological nature of food led Zinskie to study the genetics of yeast, particularly when it comes to the process of beer fermentation. While Zinskie confessed that she doesn’t actually drink beer, she has been fascinated by the evolution of beer consumption and brewing, as well as beer’s historical impact on society.

Q: How did your research lead you to study the evolution of beer?

A: I have a general interest in the health benefits of foods, specifically using foods as preventive medicine. My interest began as an undergraduate student, when I studied the health benefits of juice and wine in animal models. My main project involved analyzing the phytochemicals in cranberry juice and using the juice to inhibit the development of heart disease in hamsters. And I collaborated on a project in which we investigated the effects of wine on the “metabolic syndrome” in rats.

In graduate school I worked with brewer’s yeast as a model organism and have continued working with it as a postdoctoral fellow. Over the years I’ve spent a lot of time learning about yeast. Because of this background I naturally gravitated toward learning about beer and wine.

Q: Scientifically speaking, is it in our DNA to want to home-brew and drink beer?

A: It’s in our DNA to drink beer. Matthew Carrigan and Steven Benner, biologists at the Foundation for Applied Molecular Evolution in Gainesville, Florida, did a comparative analysis of the primate gene alcohol dehydrogenase (ADH4), which converts ethanol into fuel for our bodies. They found that our hominid ancestors evolved a digestive enzyme for alcohol, ADH4. This enzyme that metabolizes ethanol appeared around the time our primate ancestors transitioned from living in trees to inhabiting the forest floor, about 10 million years ago.

In these more distant ancestors the enzyme didn’t efficiently metabolize ethanol. Our more productive version today most likely became efficient due to our increased exposure to alcohol from our diet. Our early ancestors would have collected fruit from the forest floor. That easily accessible fruit could have been squished or the skin could have been broken, exposing its sugars to yeast and allowing for fermentation. Although the naturally occurring alcohol content would have been low, eating enough of the fruit would have had mind-altering effects on the consumer.

Although it isn’t in our DNA to home-brew, it has long been societally accepted and expected to brew one’s own beer. It was primarily the responsibility of women to brew the beer for the household. “While men were out hunting, women were out gathering the ingredients they needed to make other foods and drink to go with the wooly mammoth or mastodon,” says Patrick McGovern, a well-known and highly respected biomolecular archaeologist from the University of Pennsylvania.

Q: How did beer impact early civilizations?

A: Beer resulted from humankind’s discovery and ultimate mastery of agriculture. Beer was a great source of calories and provided sustenance and nutrients. Through agriculture humans amassed a stable supply of food, namely, cereals. The advent of farming allowed nomads to forgo the unstable lifestyle of hunting and gathering and instead start settlements by growing food and domesticating animals. The domesticated crops made it possible for small- and large-scale brewing.

The emergence of agriculture led to the development of civilizations (around 3500 BCE in Mesopotamia). The timing of the development of agriculture and civilization is location specific, so various people began domesticating wild crops at different times in history. Once developing civilizations relinquished the nomadic lifestyle, humankind was able to focus on establishing governments, making allies and enemies, and increasing societal productivity. They also domesticated wheat for both food and beer, and the food security allowed for the population to rapidly increase.

Grains are better suited to making beer rather than bread because malted and subsequently fermented grain releases sugars in a more usable form for the body. So beer offers a calorie-dense drink that is also safe from microbial inhabitants. Waste produced from quickly growing populations led to undesirable consequences like pollution of water sources. As an alternative to the tainted water, beer was a safer drink.

Beer was highly valued and thought to be a gift from the gods. Around 1800 BCE ancient Sumerians wrote the first ever “brewing recipe” in the form of a hymn to the goddess Ninkasi. Beer is also mentioned in the oldest written story, the Epic of Gilgamesh. The Egyptians recognized their goddess of beer, Tenenit, throughout their mythology. In the 3rd century BCE, Egyptian workers were paid in a low alcohol-content beer to build ancient pyramids and temples.

Q: How did modern scholars come to learn that ancient cultures brewed beer?

A: In 1953 Jonathan Sauer proposed that early grains were not suitable for bread but that wild and early domesticated grains were used to make beer. He surmised that the early grains didn’t yield enough nutritional value for use in making bread, but once processed for beer, grain provided an adequate calorie and nutrition source. Although this theory has been argued against, much evidence has been raised in its favor.

In the 1980s Solomon Katz and Mary Voigt supported the “beer before bread” theory. They argued that the “buzz” induced from beer along with its high caloric content would have motivated early farmers to grow cereals. The consumption of beer had mind-altering effects that allowed early humans to temporarily disengage from their current life. The alcohol content was enough to give the consumer a “buzz,” but the beer was also filling enough to prevent intoxication. Beer’s supplementation to early humans’ diet helped to better nourish groups who drank versus nondrinkers.

Q: What were the recipes for ancient beer brewing, and did different regions adapt those recipes in any particular ways?

A: Unfortunately, most of the recipes for beer from early civilizations have been lost to time. The oldest surviving beer recipe is part of a 3,900-year-old Sumerian poem describing the production of beer from barley, the Hymn of Ninkasi. We do know that early beer would have contained a maltose source (wheat, barley, rice, etc.), naturally occurring yeast, and water. Depending on the region additional fruits and herbs were added.

Even though we don’t have the original recipes, scientists such as Patrick McGovern have analyzed the chemical composition of residues on ancient pottery. McGovern was able to identify original ingredients from the ancient Chinese civilization Jiahu. Their ancient drinks were a “grog” that was more of a honey mead made from rice, grapes, and hawthorn fruit. Rice, being native to China, served as their cereal source, and the additives imparted flavor. For anyone interested in trying beers that would have been consumed in ancient China, Egypt, or Turkey, McGovern collaborated with Dogfish Head Brewery to bring to life the ancient recipes.

Behind the Scenes at Dogfish Head

Take a peek behind the scenes at Dogfish Head, a craft brewery in Milton, Delaware, to see how they make their signature brews and their “ancient ales.”


Q: Were there health benefits associated with ancient beer consumption or any drawbacks?

A: As I’ve mentioned, beer’s high caloric content helped nourish the growing populations in addition to being a safer alternative to the polluted water. The fruit additives would have introduced phytochemicals from superfoods (i.e., fruits and herbs) into their diet. Anthropologists have found that people in ancient Nubia recognized the medicinal benefits of beer. They used beer as an antibiotic to treat everything from gum disease to infected wounds. In the 1980s George Armelagos, an anthropology professor at Emory University in Atlanta, analyzed 2,000-year-old Nubian bones and found they contained the antibiotic tetracycline. The tetracycline would have been derived from the bacteria Streptomyces, which would have grown in the beer as it was fermented.

The current body of scientific evidence suggests that moderate consumption of alcohol, in any form, cuts down the risk for coronary heart disease, and beer contains other compounds with known health benefits, including B vitamins and soluble fiber. These added benefits would have been helpful because food was not always abundant or consistent.