During the IPA / hop-forward beer craze, many brewers saw additional haze forming in their beers when dry hopping, or adding additional hops in the fermentation process. This haze phenomenon became practically synonymous with flavorful, hoppy beer, and has led to a massive surge in interest in these “hazies” and their fruit juice-like aromatics. Throughout this time, research into beer haze has focused on malt and hops without considering or often neglecting the role yeast could be playing.
The research and development team at Chicago’s Omega Yeast Labs has made a groundbreaking discovery that links hazy beer to a specific gene, HZY1. Already known for their genetically modified yeast strains that highlight increased tropical and fruity flavors in beer fermentation, Omega Yeast’s latest breakthrough will help brewers customize their beer offerings.
In the R&D lab at Omega Yeast, the team regularly conducts experiments to see how different yeast strains act when subjected to various conditions, like swapping out recipe ingredients, altering temperatures during fermentation, and more.
“We always pay close attention to what we are seeing in our experiments,” says Dr. Laura Burns, Omega Yeast’s Director of Research and Development. “In one case, we were using a simple experiment to mimic IPA fermentations, and we found that certain yeast strains would promote haze when others did not.”
By observing these fermentations, Dr. Burns and her team discovered that some strains would create brilliant, non-hazy beer, while others would create beer with a milky, turbid haze. They tested variations in the recipe as well as the dry hop timing and the results were consistent: the samples that finished hazy were always from a group of yeast strains that the team deemed “haze-positive.”
Given that traits like fruity and spice-like flavors, sweetness and dryness in a beer’s finish, and varying levels of alcohol output are all traits determined by yeast genetics, it stood to reason that haze could also be specified by the genetics of haze-positive yeast.
These developments were what set the team on the hunt for a genetic link.
“When it came to haze, everyone in the craft beer industry was focusing on malt and hops, and we had a very clear result that certain yeast strains were promoting haze in IPAs,” adds Burns.
Using a combination of classic genetics and next generation sequencing, the R&D team was able to identify genetic changes to a novel gene that made haze-positive strains hazy. The Omega Yeast team has named the gene HZY1, for its newly discovered role in promoting beer haze. Using gene-editing technology known as CRISPR/Cas9, Dr. Burns and her team were able to delete this gene from haze-positive strains, and beers fermented with these strains were no longer hazy.
“Brewing yeast have been so extensively studied, we never thought we would be the first to identify a new gene for haze,” Burns says. “Now that we have a gene, there’s no denying that yeast play an important role in promoting haze in beer.”
For the broader beer world, this discovery blurs the line between yeast strains that could be used for NEIPAs and traditional West Coast IPAs, allowing the exploration of new flavor combinations. Brewers will be able to create new flavor profiles and enrich their brand portfolios with beers that look and taste different from anything they have been able to brew until now.