Tales From the Lab

At the end of 2018, we fully intended to write up a recap of the year and post it here, with some hints at things to come. Unfortunately/fortunately, 2019 started quite busy for us, and that task fell by the wayside. However, we have started to launch new products for 2019, and so I thought it would be helpful to explain what we’re up to. 

 

Our research program's goal is to use applied brewing science research to develop new products, as well as to understand our existing products in greater detail. We think that there are major knowledge gaps in several aspects of how modern brewers use yeast and bacteria, and we hope to address these knowledge gaps in the coming years.  

 

Last year we were able to deliver on a number of exciting projects. We completed an in-depth analysis of yeast repitching over 12 generations, and uncovered some quirks of our core ale strains in the process, revealing an elevated need for oxygen with the Vermont Ale strain. These results were presented at the MBAA/ASBC Brewers Summit in San Diego. 

 

We also had the opportunity to collaborate with colleagues at the University of Guelph and VTT (Finland) to characterize and whole genome sequence Norwegian kveik yeasts, which we published in Frontiers in Microbiology. We found that kveik are indeed quite amazingly tolerant of high temperatures and high alcohol conditions, and can produce clean beers at high temperatures. We also discovered these yeasts are genetically quite unique and are hybrids of typical ale yeast and some other more mysterious parent, which may have passed on the superior traits. 

 

We are continuing to dive deep into the genetics of our brewing strains, as well as some of the recent (re)discoveries like kveik and other landrace yeasts. We think that understanding the genetics of our yeasts in detail and passing this information along to our customers in a transparent manner will be critical to improving beer quality and innovation in an increasingly competitive landscape. 

 

Here’s the 2019 highlight reel so far

Lactobacillus blend 2.0: optimized acid 

The Lactobacillus blend 2.0 sours more reliably at a wider temperature range and shows less impact on yeast fermentation.  

Like many products, this started with a problem. A client of ours was having persistent issues with our Lactobacillus Blend, especially when it had been reused for multiple generations. The wort would sour, but the beer would not ferment. This stumped us for a while until we dove into the scientific literature and found that under certain circumstances, certain Lactobacillus strains can produce acetic acid. Acetic acid prior to fermentation can be a real stress for yeast, and so we suspect that acetic acid may have been stalling out the ferments of our client. Additionally, there were occasional reports of slower than expected acid production when brewers soured in the 40-45ºC range. 

We plundered our strain vault for alternative Lactobacillus strains, testing them in what ended up being a fairly substantial research project. We were looking for Lacto strains with low acetic acid production and a wide temperature range. We found that the L. brevis strain in our Lactobacillus Blend does produce acetic acid under certain conditions. It’s not enough to substantially alter the flavour of the beer (we’re not in Flanders territory), and in fact, may increase complexity in the Lactobacillus blend (1.0). However, under certain circumstances, it can be enough to slow down the yeast ferment. As an alternative, we discovered that an L. rhamnosus strain in our bank had some really cool properties: it produces pleasant guava-like flavours and also sours at nearly the same rate across the 30-45ºC spectrum.  

This discovery led us to test out new blends, and we found that a blend of the L. rhamnosus strain with our existing house L. plantarum strain worked quite well to produce sour wort fast, across a broader temperature range. We have dubbed this blend “Lactobacillus Blend 2.0”. We are aware that the original Lactobacillus Blend has a number of happy users, and under ideal circumstances (35-40ºC) it can produce tasty sour wort with notes of red fruit and citrus. However, we do feel that the Lactobacillus Blend 2.0 is a useful next step. This blend is already available to pro brewers, and we are launching homebrew pitches shortly. 

We also suspect there’s quite a bit of flavour diversity still locked in all these Lacto strains. We will be launching more strains as the year goes on, with a focus on shifting the perception of Lactobacillus to flavour-forward microbes used to target specific profiles and not just acid factories. Shoutout to our R&D hero Iz Netto for heading up this project. 

Überweizen: A tale of two Weizens 

 The targeted flavour profile for Hefeweizen yeasts

We have always been extremely careful about quality control, which starts with preventative measures to prevent cross-contamination of yeasts. Even prior to widespread industry concerns surrounding diastatic/diastaticus yeasts, we implemented a “risk level” system where yeasts which pose risk to other yeasts are kept physically separate, and always handled in a specific order (clean, then phenolic, then diastatic).  

However, following the great diastaticus explosion (oof), we did our due diligence and screened all of our non-Saison strains (all saison strains are diastaticus) for the STA1 gene. Lo and behold, we discovered that our Weizen II strain contained the STA1 marker gene. While it did not grow particularly fast on starch agar, we still felt it was too risky to be selling a diastatic Weizen strain, so we sought a replacement.  

We scoured for Weizen yeasts high and low and stumbled into a strain that ticked all our boxes: higher attenuation than Weizen I, focused banana esters, and low sulfur. We ran a test of this new Weizen against our Weizen II and were very impressed with how it performed. Because of how well this strain performed, we dubbed it Überweizen. The Weizen I strain is still the classic example, but we are quite stoked on Überweizen. This strain is currently produced regularly for pro and homebrew formats.  

Berliner Brett I: Expanding the Brett flavour palette 

Old Berliner Weisse bottles, colonies of Brett from one of those bottles, and GC measurement of ethyl guaiacol in the beers indicating the presence of Brett in the samples. 

Back in 2017 at the legendary Carnivale Brettanomyces, in the backroom of a big funky beer party, some magic happened. A wide selection of old Berliner Weisse bottles (some over 40 years old) were opened and the precious yeast slurry at the bottom of the bottles was retrieved. Back at the lab, we were amazed at what we found: the majority of these old bottles yielded viable colonies of Brettanomyces! We dutifully banked and sequence ID’d these yeasts, finding a near equal mix of Brettanomyces bruxellensis and Brettanomyces anomala

We are now working our way through these strains. We suspected that because Berliner Weisse evolved quite separately from other Bretty beers (e.g. lambic, English stock ales), that the cultures inside them might be unique. Additionally, folks who have used Berliner-origin strains in the modern era describe these yeasts as often more subtle, with white wine, stone fruit, and citrus character versus the heavy pineapple and funk of typical Brett strains. 

Following testing a few of these isolates in different conditions, one strain really stood out to us. This is a Brettanomyces anomala strain that was isolated from a ~40 year old bottle of Hochschule Berliner Weisse. We have called this strain Berliner Brett I, with the intention of launching more Berliner-derived Bretts in the future. Berliner Brett I is subtle in character, which is something we wanted - a subtle Brett that integrates into the character of a beer, instead of overpowering it. Don’t get us wrong - we do love high-octane Brett character - but sometimes we crave subtlety. This makes it suitable for delicate beers like Berliner Weisse, grisettes, saisons, and pale ales. We’re even testing it in a Brett lager where it is showing some promise.  

Berliner Brett I produces notes of white wine and citrus, and in repeated sensory trials was noted as being quite unique. Since it is Brett anomala, it won’t consume residual starch/dextrin as aggressively as Brett brux strains. It can be used in copitch or in secondary fermentation. This strain is available to pro brewers, and homebrew sized pouches are on the way. 

Looking forward 

Our research program has quite a few ambitious goals to bring new flavour and new products to the craft beer industry. We are in the process of overhauling our Lager yeasts, emphasizing recent high-performing products like Isar Lager. We are whole genome sequencing all the yeasts we can (…afford). We are continuing to research diastatic yeasts and work on solutions for brewers to detect problems easier. In light of increasing demand for non-alcoholic/low alcohol beers, we are seeing the dozens of maltose-negative yeasts in our bank in a new light. 

But most of all, we’re stoked to be able to do interesting experiments, turn those experiments into products, and help brewers across the country make any beer they want to make, from reliable flagships to wacky fruited kveik berliners. If there’s an idea you have for a product or flavour profile and you don’t know where to get started, please reach out. And if you have any problems with fermentation, also reach out. Your feedback and excitement help focus us on the fermentation challenges that matter. Together we will move fermentation forward.