A Unique Chance for Breweries and Craft Beer Lovers to Advance Sour Beer Fermentation

A Unique Chance for Breweries and Craft Beer Lovers to Advance Sour Beer Fermentation

by Mark E. Lasbury for Indiana On Tap

Fellow craft beer nerds and professional/amateur microbiologists: here’s a project you can really dive into and nurture your geekdom. Dr. Matt Bochman of Indiana University has just started a project to help the craft beer industry learn more about the organisms that are working in spontaneously fermented and mixed culture fermentation sour beers. It’s a crowd funding project, but not for a product, instead this an information and knowledge gathering endeavor that could help the entire craft beer industry.

If you’re in brewing (professional or home) and want to have some deep knowledge about your cultures, here’s your chance. If you’re just a beer fan and want to see the knowledge base about sour beer organisms grow and be spread throughout breweries, here’s your chance. If you’re a science geek and want to delve deeper into the biology of sour beers, then you’ve got a chance to help too.

Through his laboratory at Indiana University (he’s an Asst. Prof. in the Dept. of Molecular and Cellular Biochemistry), Matt and his grad student Renan Piraine are looking for as many brewers/breweries to donate $100 and submit an organism sample of their sour beer fermentation program. Smaller donations will be accepted as well to help defer costs of the project, and all donations will go through Matt’s IU research budget. See the crowd funding experiment page for more details of the project (here) and a great video that explains the goals of the plan.

Matt Bochman (right) with Caleb Staton, previously of Upland Brewing. Bochman’s lab has done significant work for Upland concerning sour beer fermentation. image credit: Newsroom of IU-Bloomington

In exchange for the donation and sample, the brewery will receive the identity of all known the species present in the sample, the numbers of each species present, and a comparison of the similarities and differences between the samples submitted. The data will be obtained via a deep sequencing protocol, with quantitative aspects to give relative numbers of each organism type. There are even protocols in place to help identify hybrid organisms (strains that have traded some DNA), and even new subspecies via degenerate primer sequencing.

Backers will receive all this information so that they can better characterize their fermentation organism soups, and can rebuild them if needed/wanted. As the Experiment website states, “Many brewers, at both the professional and homebrew levels, start making sour beers by using bottle dregs (i.e., the microbial slurry found in bottle conditioned beers) to inoculate their wort. Others mix defined cultures of SaccharomycesBrettanomycesLactobacillus, and/or Pediococcus to create a “house” mixed culture, but these blends will evolve over time with repeated use. The evolution of these cultures affects the beer – and not always in a positive way. If we knew what common bacterial and yeast species (and their relative abundances) were found in “good” souring cultures, we could build the mixed cultures from isolated species to create house cultures or replace souring cultures that have evolved away from their desired sensory output.”

In cases of flood or fire, of contamination or microbial shift, it would be great to have a “recipe” as it were to go back and reset/rebuild a brewery’s cultures to the point in time when the sours were coming out great. Plus, there may be instances where new species or subspecies will be identified. Think of how helpful it could be if a brewery’s house culture could be advertised as unique to their patrons.

The funding campaign is open for thirty days, and started July 1st. Matt’s Experiment web page (here) also has contact information to discuss the donation process. Of course, you don’t have to have a sample for characterization and deep sequencing, I’m donating just for the love of science and beer. Matt and Renan need a minimum of 21 samples for analysis to make the project work. As of July 5, Matt has received almost half of the needed donations, but just because they need 21 samples at minimum to make this work, it doesn’t mean that 21 is the target. Let’s get them as many samples as possible, there is no maximum for the project and the more samples analyzed, the stronger the over all data will be.

Only so much can be learned about species an types of yeast and bacteria by looking at them. To get the real info. you have to isolate DNA and sequence them. image credit: American Homebrew Association

First, there are a few things to get out of the way to make the breweries feel better about sending organisms; after all, these samples represent some of their best trade secrets. 1) Samples can be donated anonymously so that no other brewery could possibly know what sample is yours or even if a sample is yours. 2) No one, not Matt, not IU, and not his start up company Wild Pitch Yeast will be banking samples for later use. No beer will ever be made from what you send in. 3) All data on genomics and typing/screening will be made available to the public. There will be no hoarding of data for use; this is a project to help all the breweries.

That being said, the possibilities for the data in the future are almost limitless. If sensory experts could be brought in to objectively determine flavor and acidity profiles from beer produced from each culture and the cultures could be compared by constituents, then a flavor database could be built showing how combinations work together and, if enough samples are analyzed over time, what each organism type can contribute to a beer for a given wort and fermentation conditions.

There is also a second set of data that will be generated during this project, born from something Matt thought about during a Sour Wild Funk Fest pre-party at Upland Brewing in March. Many of the visiting breweries brought some dregs from a wild or mixed culture fermentation; Upland combined all of these into a single pitch in order to create a collaboration beer that may used or next year’s festival (or perhaps the one after that).

Matt began wondering what organisms might win out in such a fermentation. When two or more organisms are grown together, some will naturally compete better and end up in greater numbers. Often, one species will actually put out compounds to suppress growth of other organisms. It’s a war in that fermenter! Matt thought that this could be run like a March Madness tournament (he calls it Mixed Culture Madness), where submitted samples could be pitted one against another in head to head battles. Since the genetic analysis would tell us what and how many organisms exactly went in at the beginning, characterization at the end of the battle would tell us whose organisms were left.

The Sour Wild Funk Fest was in no small part the genesis of this project. image credit: Sour Wild Funk Fest

Unfortunately to do a tournament like that would take months, if not years. However, the principle is still viable – just dump everyone in the pool for a fermentation, and then harvest organisms several times, perhaps once a month, and see which organisms grow more abundant and which ones die off or are reduced. Data from this type of experiment will help brewers build stronger cultures, or help them to determine what flavors are produced at what time in the fermentation process, so they cold consider how long they might like to let a beer go.

Look for collection of samples to be done by September of this year, and DNA isolation to be completed a bit over a month after that. Sequencing will take place before December and correlate data should be available to backers by the first of the year. The data will be posted in the Lab Notes section of the Experiment website.

Pass the word and the website address (here, again) for the venture to both home brewers and professionals. This is a unique and innovative project that has the potential to help both individual breweries and craft brewing as a whole. If you don’t have a sample and/or $100 to donate, give something less and still be a part of moving brewing forward. Indiana On Tap will stay on top of the story and report on how things are going all along the way.


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