The Sour Beer Microbiome — Exploring Tiny Fermenters

Souring beer with different levels of “haze” — Photo Credit

Humans are gravely outnumbered. In a single handful of fertile soil, there exist more microbes than humans that have ever lived on the planet. Their rapid reproduction rate makes them highly varied and very sturdy. Two distinct strains of E. coli can have more genetic variation than a human and a platypus, and microbes live everywhere from hot springs and nuclear waste, to rocks two miles beneath the Earth’s surface. Sometimes microbes give us colds or parasites, but the vast majority of microbes are resoundingly peaceful creatures. They’re happy to keep invaders from colonizing our skin, make our vitamins, or help us ferment food.

One favorite fermented food is beer. Sour beer is especially sublime. At its best it can taste like a “liquid Sour Patch Kid”. At its worst it can give off vibes of nail polish remover and dirty diapers. The lack of consistency in sour beer production is a major issue for breweries — a bad batch wastes money and resources. Matthew Bochman, an assistant professor at Indiana University, and Jeff Young of Blue Owl Brewing collaborated to help solve this problem. Their Experiment campaign focused on uncovering the microbiome of sour beer in order to determine what makes a good batch. I gave Matt a call to learn more about how this project came together.

Can you tell me about who you are?

I’m an Assistant Professor at Indiana University. I’ve been here for a little bit over three years now. I’m a yeast guy, so I’ve been in research labs in one capacity or another for probably about fifteen years now. I’ve always used yeast as my model system and that’s how I got into some of this. I was also a home brewer early on and I just figured, why not combine two things I really dig. I would bring strains home from the lab or keep brewing strains in my lab freezer and things like that, so I’m just overall a pretty nerdy, yeasty kind of guy.

Can you tell me about where you grew up and whether you were always interested in science?

I’m originally from just outside of Pittsburgh, so I’m a Pennsylvania boy, born and bred. I think even from an early age, I was always into nature and science and technology and things like that. As a kid, I would take apart radios and try to figure out how they worked. I never did, but I was interested in what was going on inside of them. I spent a ton of time outside just playing in creeks and finding different living things and just enjoying that type of thing. I got a chemistry set for a birthday when I was young. I thought that was awesome until I realized I couldn’t do anything dangerous with it. I’ve always had an affinity for natural sciences.

Did you always know that you wanted to be a scientist?

I knew I wanted to be some sort of scientist. I went to a college that was known for having a good science curriculum, but I didn’t really know what I wanted to do necessarily. My math wasn’t as strong as other subjects, so physics was probably out. When I first got to college, I just enrolled as a biochemistry major because I figured that way I’d get some biology, some chemistry and I’d just see where I fit. I did tend more towards the biology as time went on.

You collaborate with Jeff Young on this project. Can you talk about how your team got together and how you thought of the idea for this experiment?

Jeff gets all the credit. This was basically his baby. My lab, early this spring, published a paper on solving a particular problem with sour beer. He somehow or another ran across a copy of it and just emailed me and said, “Hey, really enjoyed the work. It was great reading that somebody’s researching this.” As a sour brewer, he was definitely interested in what was going on and just had some questions for me about the technique and the paper and things like that.

A sneak peak into Blue Owl Headquarters — Photo Credit

As we emailed back and forth, he was like, “I’ve got these ideas.” He also comes from a science background. He was an analytical chemist in his former life. He just peppered me with questions. “Hey, could you do this? Is this possible? Would it be interesting to look at this?” He really sent me a whole bunch of ideas. The one that sparked my interest and I thought was probably most doable at least as a short-term project was the sour beer microbiome thing. That was all Jeff.

Could you describe what your sour beer microbiome project is about?

The technique that Jeff’s brewery Blue Owl uses to make their beer is they basically inoculate it with some amount of grain so whatever microbes, the yeast and bacteria, that are naturally present on that grain are what sours his beer. What he’s found by basically trial and error is that not every batch is the same. There’s a consistency issue and the hypothesis is that, well, there are differences in different lots of grain he’s getting in and those differences are in the native microbes.

Photo Credit — Blue Owl Brewing

We’re really interested in trying to figure out how microbes change based on geography. If you look at grain from North America, South America and Europe, what are the differences, even with the same provider over the course of a year? If we got stuff from early harvest or stuff that’s sat around in a warehouse, how does that change things so that when Jeff is brewing, he can triage a batch of malt that comes in or he just knows straight away, “Okay, this is European malt. It’s going to have this sweep of microbes in it and we can expect that it’s going to sour in twenty-four hours instead of forty-eight” or whatever that might be. He’s just looking for some consistency in his process and the intellectual curiosity is, “Why isn’t it consistent now? What’s really the difference between batch to batch?”

How did you decide that you wanted to crowdfund? Was it a new thing for you?

It was definitely new for me. Like I said, Jeff had the idea and I said, “That’s interesting to me. I’ll work up a budget and let’s see where we’re going to be at.” Like most biology, it was more expensive than a civilian might think. He owns a small brewery. It’s relatively new. I think the one year anniversary is coming up here in a couple of weeks. Their R&D budget just isn’t there for that type of project, so we discussed maybe writing a grant to the Brewer’s Association, which is sort of the national guild for professional brewers. Otherwise, we didn’t have a lot of options short of taking it to the people and seeing if we could excite them and get them to help us fund it.

This all happened in a magic week where I got the emails from Jeff and we started to talk. I was actually emailed by and they asked if I had any fermentation science projects I can consider putting up because they were going to run a fermentation challenge. They’ve since rescheduled it, but by that time, Jeff and I were excited and we just ran with it.

What would you say was the most difficult part of running your campaign and what was the most rewarding part?

It was tough for me that Jeff and I are separated by distance and time zones. It was just hard for us to coordinate things just to write the different pieces for the project and get feedback from one another and get everything posted and live on That’s just a fact of modern life is people are increasingly separated but doing things electronically. I’m sure I’m not the only one that’s had that problem. The best thing was just seeing how many people got excited about it. Even if they could only donate five dollars, people were interested in what we had to say and what we wanted to do. We got people at all levels. There were professional brewers that kicked in some money, home brewers. Even my mom could.

What advice would you give your younger self or anyone who’s starting out in science or wanting to pursue science as a career?

That’s a loaded question! I guess I would say to keep an open mind. As I was coming up through the ranks, pretty much what you did was you’d go to grad school, you’d get a PhD, you’d do a post-doc, and then you try to get a faculty job somewhere. That was the career track for everybody. This was also the time that the economy died, 2008–2009. People started to realize there were more post-docs being produced than there were jobs opening up and all these things so just because that was the one job track that everybody had thought of and taught toward. There’s tons of other stuff a person with an affinity for science or a PhD or whatever it might be could do. I really like to write and I could see in an alternate universe me turning into a science writer instead of a scientist. I would say just don’t put on your blinders. Keep an open mind.

Is there anything else that you’d like to say that you haven’t said so far?

Of all the science I’ve ever done, I don’t want to say this is necessarily the most rewarding or the most fun, because it’s all been fun for me. I geek out about this kind of stuff. But, it’s been a nice change of pace because the average person understands it. You don’t necessarily need a specialized vocabulary or anything like that to get it. People get excited about beer, people are interested in beer. It’s just been nice to have the average person take an interest in the stuff that I do, whereas the other ninety-nine percent of my time, it’s over my own head some days.

Matt Bochman and Jeff Young raised $6,246 from 68 backers on June 5th, 2016 and since the end of their campaign they’ve successfully ran a pilot experiment. Read more about what they found here!