Biotransformation 101 and recipes using LalBrew Pomona™

IPA is still the largest category and primary driver in growth for craft beer. Homebrewers and professional brewers alike are constantly looking for ways to differentiate their IPAs from the competition. You could increase your hop usage rates, but many brewers are leveraging biotransformation to help optimize hop aroma. 

What is biotransformation? 

Biotransformation refers to the process of yeast modifying hop aroma compounds during fermentation. A decade ago, biotransformation was as simple as adding hops during active fermentation. Hops + Yeast = Biotransformation. Simple, right? Our understanding of biotransformation has come a long way since then. We now understand that biotransformation depends on three main factors: Hop variety, hop addition point, and yeast strain. No surprise as yeast is responsible for the production of 42% of the aromatic compounds.

Hop varieties will vary in the quantity and relative composition of aroma compounds. The two main categories of aroma compounds are terpenes (citrus, floral) and thiols (tropical fruit). Aroma compounds may be present as a free aromatic compound or bound as a non-aromatic precursor. 

Hop addition point is a balance between increasing the total biotransformation and reducing the loss of free volatiles due to CO₂ scrubbing. Hops rich in precursors should be added to the kettle, whirlpool, or early fermentation to allow yeast to interact with these compounds and release free volatiles. Hops rich in free volatiles should be added later in fermentation so that these compounds are not lost with the CO₂ produced during fermentation.

Yeast strains will vary in their ability to release free volatiles from terpenes and/ or thiol precursors. Different strains may also be able to convert specific terpenes or thiols into different compounds with new aromas. For example, geraniol (floral) may be converted into betacitronellol (citrus). 

Biotransformation recipes for LalBrew Pomona™ 

Need some examples to get you started? As part of the release of LalBrew Pomona™ in homebrew sachets, we have produced a series of six different recipes that highlight the biotransformation potential of this strain. What makes these recipes special is that we go into detail about how the recipe was created, why specific hop varieties were chosen, and how the hop additions serve to maximize specific aromas in the beer.

Pacific Rim Hazy IPA promotes the citrus aroma by the release of aromatic terpenes from glycoside precursors. Watch this video featuring David Heath to learn more about this recipe.

The Rejoin IPA promotes the citrus aroma by converting geraniol to beta-citronellol and boosting hop esters. 

Spinning Yarns is a session IPA with New Zealand hops that pairs well with the ester profile of LalBrew Pomona™. 

American Wheat Ale showcases how terpene precursors from coriander seed can increase terpene aroma in the beer. 

Life’s a Peach IPA shows off the peach character of LalBrew Pomona™ by pairing with hop varieties known for a peach aroma. 

Peaches & Cream Triple IPA is an admittedly excessive recipe that brings everything together by promoting the release of geraniol from glycoside precursors, conversion to beta-citronellol, and selecting hops to promote tropical fruit and coconut aromas. 

Are you planning to brew one of these recipes? If you do, tag us on social media with the @lallemandbrewing handle. We  would love to see your photos and videos. 

Find all our LalBrew Pomona™ recipes here