Engineered Yeast, Terpenes & the Potential for Hop Substitutes

With the current craft brewing landscape dominated by trends of aggressively hopped IPA’s, it is difficult to picture a time when hops did not play a pivotal role in beer.  However, non-hopped beers are nothing new, dating back to the 3rd millennium BCE when ancient Sumerians brewed beers without hops.

Don’t be surprised to see an increase of craft brewers moving even further away from the days of old.  Some breweries are adding terpene concentrates to new experimental beers. In fact, Lagunitas Brewing recently released a brew called SuperCritical Ale, infused with terpenes derived from cannabis.  While the terpene concentrate, known as terp drops, are typically used for amplifying the flavors of cannabis, it certainly has shown potential for applications in brewing sphere.

In most modern beers, hops are boiled to provide distinct bitterness, aromatics, and a flavor profile that provides balance to the sweet malt characteristics of the unfermented brew, known as wort.  In ancient beers before the introduction of hops, plants and herbs such as wormwood or juniper would used in efforts to achieve a similar result. This herbal mixture, often called gruit, was extensively used before hop infusions became popular.

Over time hops were discovered and began to be used in beer making, quickly becoming a mainstay in the brewing world due to their remarkable qualities. With advances in human agricultural skills, hops became much more prevalent and hop infused beers began to become the standard.

Today modern hop farming has been elevated to an unprecedented level, allowing different hop strains to provide unique bouquets of aromatic and flavors. These hops can boast incredibly wide ranges of flavors from citrus and fruity, to herbal, earthy and spicy.  One reason for this is that hop flowers secrete essential oils that are rich in terpenes. These terpenes are organic compounds that are responsible for the highly aromatic fragrances found in all sorts of flora, commonly including trees, flowers, herbs, spices, and fruits.

Researchers lead by biochemist Charles Denby, at the University of California Berkeley, have investigated the complexities behind the terpenes responsible for common flavors found in the popular hops like the Cascade variety.  By implementing engineered yeast strains capable of biosynthesizing some of these terpenes, their team was able to reproduce the same hoppy flavor without actually adding the hops. Sensory analysis confirmed their results, as the finished beer achieved similar aromas and flavors that are imparted by the use of Cascade hops.  A double blind tasting experiment with a panel of 40 participants at California based brewing giant, Lagunitas Brewing, came to the same conclusion of distinct hop character and qualities.

However, the study also indicated that there are complex environmental, genetic, and process factors that surround the precise production of specific flavors.  Due to these challenges, don’t expect this genetically engineered yeast to take over the brewing world just yet.

About the Author

Jack Plexico is a former brewer from North Carolina, having eight years of experience in the retail, distribution, and production tiers of the craft beer industry.  Originally working in beer throughout New York City and North Carolina, he is currently based out of Ho Chi Minh City, Vietnam.