Can science create the perfect craft beer?


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Can science create the perfect craft beer?

India pale ale. Lager. Stout. Porter. Witbier. Pale ale. Kolsh. These are just a few of the unique styles of beer that can be created using water, malted grains, varying amounts of hops, and different types of yeast. Craft and home brewing have grown in popularity over the past decade, becoming somewhat of an art form.

But as one of our guests on this episode put it, ‘brewing beer is a science’ too. In this Tiny Expedition, we set out to discover just how much science contributes to the brewing industry and whether it can help create the perfect craft beer.

Craft breweries initially began popping up along the west coast because that is where the majority of the barley and hops are grown in the United States. Brewers in the eastern half of the US must import these important ingredients from growers out west. It turns out scientists are trying to create regional varieties of barley and hops that can be grown across the US.

Science is also helping to improve another key ingredient in beer: yeast. Gene editing technology is being applied to yeast to help it express different flavors or unlock hidden flavor compounds in barley and hops.

Listen to Tiny Expeditions Season 2, Episode 4: “Can science create the perfect craft beer?” to journey into the craft brewing industry and learn how scientists are trying to create the perfect locally sourced craft beer.

Behind the Scenes

Humans have been enjoying fermented beverages like beer for thousands of years. Although it is difficult to attribute the invention of beer to any one culture or time period, evidence of beer production dates back about 5,000 years to the Sumerians of ancient Mesopotamia.

The first brewery in America opened in the early 17th century in the area now known as New York City. Since then, the brewing industry in America has ebbed and flowed with the changing cultures of the time. Prohibition and war times were especially hard on the beer industry but it has bounced back stronger than ever.

It turns out, Americans love their beer. The number of operating U.S. breweries grew from about 280 in 1990 to more than 8,880 in 2020. But have you ever thought of how your pint of craft beer is made? It surely does not just magically appear at your local craft brewery. Beer brewing is a unique mix of art, science, imagination, and a lot of hard work.

Beer brewing process

There are four key ingredients in most beers: malted barley, water, hops and yeast. You heard about how science is helping to improve and reimagine some of them in this episode of Tiny Expeditions but we did not get into the science behind the actual brewing process much. Let’s briefly discuss the brewing process.

The process of brewing beer begins with harvested grains. Traditionally barley is the base of many beers but wheat, oats and rye are sometimes used. The grains must be prepared for brewing through a process called malting. Basically malting allows the grains to partially germinate which helps form the enzymes and starches necessary for the fermentation step.

In the mashing step, malted barley is combined with hot water to produce a sugary mixture. This step activates enzymes in the grains that causes starch in the malt to break down and release simple sugars. At this point, the spent grains are removed from the liquid portion (called wort) and hops and other spices are added for bitterness, flavor, and aroma.

Once the hop-wort mixture has boiled, it is cooled down and moved to a fermentation tank. Here yeast is added to the mix. The yeast eats the sugars that were produced from the grain starch and creates alcohol and carbon dioxide (carbonation).

The liquid is fermented for several days to weeks depending on the type of beer that is being produced. After fermentation, the beer will rest for a few days to weeks to allow full development of flavors and textures. After resting, the beer is ready for carbonation, filtration, and packaging into casks, kegs, bottles, or cans.

Now that we understand how each of our star ingredients play into the development of a pint of beer, let’s go behind the scenes with our guests from the episode.

Barley

Jeremy Schmutz (left) and his team at the HudsonAlpha Genome Sequencing Center are experts at producing, analyzing and interpreting genomic data on economically important plants to improve crop breeding and other agricultural practices. It was their work on the early barley genomes that got Jeremy and the other leaders of the HudsonAlpha Center for Plant Science and Sustainable Agriculture first thinking about growing barley in Alabama.

Although barley was historically grown in Alabama, most of the barley in the United States today is grown in Montana, Utah, Colorado, Wyoming, Washington, Oregon, and California. Barley in the Midwest is harvested late July to end of September. Because Alabama’s winter climate is mild, the team wondered if barley could be grown in Alabama over winter between farmers’ other crop rotations. 

Barley trial at the Belle Mina Auburn field station

The team at HudsonAlpha, along with collaborators from Auburn University’s departments of Crop, Soil and Environmental Sciences and Entomology and Plant Pathology, and Alabama A & M’s Winfred Thomas Agricultural Research Station, are developing a pilot pipeline to import and test new crop varieties that could be deployed by Alabama farmers.

Like we mentioned in this episode, the team at Alabama A & M planted 25 varieties of barley at their field station while the team at Auburn planted about 50 varieties. The image to the right shows the Auburn field pilot planting.

Hops

Photo by Markus Spiske on Unsplash

Like we learned in this episode, hops are the flowers, or cones, of a plant called Humulus lupulus. Hops do a number of things for beer. They help to keep beer fresher, longer and help beer retain its head of foam. And probably their most popular attribute is adding “hoppy” aroma, flavor, and bitterness to beer. 

Americans have been growing hops since early colonial times. The first commercial hop production was a 45-acre garden established in 1648 to supply a brewery in the Massachusetts Bay settlement. Massachusetts remained the country’s most important hop supplier for the next 150 years, until production expanded to other New England states. 

Haley Hale (left) and Dr. Sarah Carey (right) with a hop plant

Today the majority of hops are produced in the Pacific Northwest (WA, OR, CA, ID). About 75% of the hops are grown in Yakima Valley, WA. That means that breweries outside of the western US must import hops, often across the entire county.

Dr. Sarah Carey (left) hopes to help bring hops to the eastern US by creating reference genomes for the entire genus of Humulus. To create these reference genomes Dr. Carey extracts all of the DNA from hop leaves. Then she sequences it and then assembles it into references. The reference genomes can be used to compare across the groups to see how the genomes have changed across these different varieties and species. The team hopes to identify genes that give hops a growth or survival advantage outside of its normal environment.

Yeast

Yeast is a single-celled living organism that belongs to the fungus kingdom. These tiny microorganisms have long been an important component of baking and brewing. Yeast is the main player in fermentation and is the most important element of making beer alcoholic and carbonated. Yeast convert the glucose from hops and grains into ethanol, or alcohol, and carbon dioxide which is used for carbonation. 

It turns out yeast is also a major contributor to the flavor of beer as well, which is not something many of us might think about. The type of yeast used in the brewing process defines the beer. Dr. Josh Clevenger (right) really opened our eyes to just how much yeast can change a beer’s flavor by home brewing us a few side by side comparisons of beer using traditional yeast and yeast that has been genetically modified to create or express different flavors.  

Our first pairing was the traditional Hefeweizen and a beer brewed with the Omega Bananza™ yeast. The Hefeweizen had that traditional banana and clove flavor. But when we took a sip of the beer brewed with Bananza, the clove flavor was absent. That’s because unlike the yeast traditionally used to brew Hefeweizens, Bananza is non-phenolic which means it is incapable of producing clove flavors.  

Photo by Jouwen Wang on Unsplash

Next we tasted a pair of beers that packed a little bit more punch. One of the beers was brewed using Omega’s Sundew™ yeast, which is another non-phenolic yeast. Sundew is incapable of producing the clovey flavors and instead produces a juicy strawberry, passion fruit, pears and stone fruit flavor. It had a subtle fruity flavor that was easy to drink and would be refreshing for a day at the beach. 

Dr. Clevenger paired this one with a beer brewed with Omega’s Comic Punch™ yeast. Cosmic Punch was developed to transform compounds found in malt and hops to release thiols, which are aromatic compounds with tropical flavors like grapefruit, passion fruit, and guava. So this yeast is basically unlocking flavor compounds in malt and hops that would not be experienced otherwise. The beer definitely packed a punch with the tropical flavors compared to the beer brewed with the Sundew yeast. 

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