What the heck are thiols?

Wynkoop Brewing, Mirror Image Brewing, & Fermly Labs - Imperial Hazy IPA collaboration day

So you’ve been hearing about thiols or thiolized beers or thiolized yeast but you have no idea what these words mean or how it impacts your beers. We asked John from Inland Island Yeast Labs to give us the scoop so you can be in the know before trying the nine beers featuring thiols at Collaboration Fest.

How does a brewery become a standout in a craft beer market saturated with Juicy IPAs and clean, crisp lagers? One of the biggest trends in brewing these days is making beers with thiol boosters or thiolized yeast strains. For decades, brewers have been pushing the flavor envelope by designing the bitterest, juiciest, or most interesting beers through the addition of more and more hops, and then through the addition of newly developed hops, purposefully bred for specific traits like tropical fruit aroma. However, there are limitations to how many pounds of hops can be added to a given volume of beer, and new hop varietals take years to develop. Brewers were asking for another tool to use when trying to push recipe innovation. Lucky for brewers, scientists also like beer so something awesome was bound to happen.

This is where Thiols enter the conversation. Read on if you want to know the science. It was understood that plants such as guava and passionfruit, but also including beer ingredients like barley and hops, produce a flavorless molecule called Glut-3MH. Through the activity of naturally occurring plant enzymes, Glut-3MH is converted into a flavor-active thiol called 3MH. Simply cutting into fruit like guava and passionfruit is proof that these plants are very efficient at converting Glut-3MH to 3MH. However, due to low enzymatic activity, traditional beer ingredients like hops and barley are not efficient at the conversion. This is where science steps in and yeast is developed through genetic modification or breeding that increase enzyme activity and help to convert flavorless compounds like Glut-3MH into potent flavor-active thiols like 3MH. This process is generally called thiol biotransformation and is capable of increasing 3MH production by >100X in some cases. This has also allowed brewers to use hops that were not seen as being high in tropical flavors, but actually have high levels of unlocked Glut-3MH, to make tropical fruit flavor driven beers.  

A new frontier beer recipe experimentation now exists where a balance between Glut-3MH availability and thiol biotransformation is key. From obscure sources like the ground up skins of Southern Hemisphere Pino Grigio grapes, new ‘thiol boosters’ have been developed to flood a beer with flavorless thiol precursor and push as much thiol biotransformation as possible. Even beer styles like lagers, lending themselves to clean and crisp flavor profiles, are now getting the thiol booster and thiolized yeast treatment, creating a new spin on old styles.

– John Giarratano, Inland Island Yeast Laboratories

Featured thiolized collabs

Click on each collaboration to learn more.

Beer: Thunder Thiolz – Triple IPA

Story: These two breweries have had a long lasting friendship but have never collaborated before. Both teams wanted to experiment with thiolized yeast which extenuates the intense juicy, tropical flavors and aromas from a hop forward IPA. This beer does just that with a triple punch of hops, flavor, and aromas with a kick.

Beer: Imperial Thiolized Pilsner

Story: Los Dos Potrillos and River North connected over a couple tacos during the 2023 GABF Saturday Session. Members of both breweries used to work together in the early days of their brewing careers so the bond formed quickly. Los Dos specializes in clean lagers and River North specializes in just about everything, including huge ABV beers. Naturally, we wanted to make a high ABV Pilsner with exciting hopping techniques. This imperial Pilsner is mash hopped with Citra and late kettle additions of Nelson Sauvin and Medusa.

Beer: Colfax Hipster – Imperial Hazy IPA

Story: A thiolized IPA to compete with the aroma of the vape haze lingering in the beard or wide-brimmed felt hat from the show at Red Rocks last night. If this beer was a car, it would be a Toyota Tacoma with a “NATIVE” sticker, dirty from the last snowfall but won’t get washed because it looks like they drove it in the mountains, when in reality the only thing it summited was that pile of snow in the warehouse beer parking lot, on the way to pick up another hype beer. In an effort to understand the rampant presence of Carhartt plaids and North Face Fleeces on the longest street in America, a scientific approach to the creation of this much-touted beer style was necessary. Putting their brewery beanies together, Mirror Image and Wynkoop, along with brewing laboratory Fermly, has collaborated to create Colfax Hipster.

Beer: Over the Sunny Phantasm Falls – Phantasm Lager

Story: Jason and Jessie at Over Yonder have been wonderful friends, mentors, and resources over the last few years as Matt and Melanie made Sunroom Brewing a reality. Over Yonder is just down the road from Matt and Melanie’s house, and Matt and Jason have been talking through recipes and brewery operations since Matt’s homebrewing days. It’s surreal and really special to be able to collaborate on a beer as fellow brewery owners this year. Phantasm is a thiol derived from Saviogion Blanc grapes found in New Zealand.

Beer: Episode 1: The Phantasm Menace – Thiolized Hazy Pale Ale

Story: This beer is the first collaboration brew between Cabin Creek Brewing (Georgetown, CO) and Soulcraft Brewing (Salida, CO) and marks the return of our former head brewer and now Soulcraft brewer, Michael Kida. This brew will be the first attempt at brewing a thiolized beer for both breweries. We are excited to welcome new and familiar faces to the brewery to dive into a new and developing area of brewing science.

Beer: West Coast IPA brewed with Thiolized yeast

Story: The story that really kicks it off for Telluride Brewing and Alan at Live Slow comes from the Colorado Brewers Rendezvous in Salida about 10 years ago. Our Co-Founder Tommy and Art Director John were working the fest when a belligerent attendee stole our banner. John asked for it back and the guy punched him! John had to go to the hospital and Alan helped pack up all their gear. Over the years since we have all bonded over our love of solid craft beer and bluegrass music. This collaboration is long overdue! STOKED to celebrate the opening of Live Slow Brewing!

Beer: Thiolized West Coast IPA with Grapefruit

Story: We’re bringing back an IPA trend of yesteryear (the Grapefruit IPA, you remember that one right?) and combining it with a brand new thiolized yeast strain – Star Party. Will we blast off into a new dimension of fresh squeezed passionfruit and ripe grapefruit juice, with a classic, dry west-coast body? The answer can be found at the 2023 Collaboration Fest.

Beer: Star Party Snow Clad – Modern Pale Ale

Story: What if Ken Grossman was a 21 year old vaping hype brewer? This modern take on a classic American Pale Ale is brewed with a thiolized Chico Ale yeast and brewed with massive amounts of Cascade and BRU-1 Lupomax hops. Tropical fruity hop flavors and intensely drinkable

Beer: Alligator Lizards – Double Cosmic New England Style IPA

Story: We decided to use the Thiol producing Cosmic Punch yeast and Phantasm powder and an all star hop load to unlock intense tropical and citrus aromas and flavors in this Double Cosmic NEIPA. The collaboration was born between a deep connection to Garrett and Juice’s Maine upbringing. Just a couple of kids from Southern Maine brewing Dank NEIPA’s in CO.