exploring thiolized IPAs, one level at a time

For about a year now, we have been exploring an emerging trend in IPA production, it’s a subset of the hazy and juicy IPA family that many are referring to as “thiolized IPA”. Before we dive in deeper, let’s take a quick second to overview what this new term means.

Thiols are sulfur compounds, produced by certain yeast during fermentation, which are highly aromatic and have characteristics of over-ripe, tropical fruit. The mechanism for the creation of these compounds is an enzymatic process, which can occur both inside and outside of the yeast cell, that converts molecules known as “precursors'', found in various types of plant matter, into the aromatic “thiol” compounds that we are aiming to maximize in these beers. There are many sources for these precursor compounds, they can be found in traditional brewing ingredients like hops and grain but probably one of the most notable sources for these precursors is grape skins. The wine industry has long been aware of thiols and they’re particularly important to a varietal produced in New Zealand called Marlborough Sauvignon Blanc, providing the distinctive notes of grapefruit, passion fruit and guava that the style is uniquely known for. It’s no coincidence that this grape varietal has been making a splash in the beer industry of late in the form of a powderized grape skin product, derived from the Marlborough Sauvignon Blanc grape, called Phantasm. We have used Phantasm in several beer series over the last year, most notably our Phantastic and Phanny Pack series, as we have familiarized ourselves with the mechanics of thiol production, but in the process we have discovered that there are a whole host of inputs that we can play with to maximize thiol production in these IPAs.

When we first started experimenting with Phantasm and the creation of thiolized IPA, we didn’t have a super clear road map to work with. Most of our experimentation was a series of somewhat random attempts to combine a handful of products and techniques, supposed to increase thiol production in beer. We’ve experimented with Phantasm, malted grain and hops, all as sources for the precursors to thiol production, but one of the most important keys to the process has been the use of thiolized yeast. These yeast are strains that have been genetically modified to express elevated levels of an enzyme called carbon sulfur lyase, it is the enzyme responsible for the conversion of these precursor compounds into the aromatic compounds we are aiming to create. So now, after a year or so of more crude and haphazard experimentation, we are taking a step back and re-starting, from the ground up, with a new series that will explore every parameter of thiolized IPA creation one level at a time.

This brings us up to this week, as we introduce our newest series, dedicated to further exploring and understanding thiol production in IPAs, called “Levels''. With this new series we are following a much more structured road map in order to see the effect of tweaking each individual parameter more distinctly. We plan to reiterate and isolate out parameters that we have already played with while also introducing new ingredients and methods to the fold. You could picture the journey we’re embarking on like an old-school, RPG video game, exploring a dark map, with a core journey in mind, but stopping along the way to engage in side quests that add further complexity to the whole. On each “Level” we will focus in on an area of experimentation and test as many permutations as make sense to explore each level before moving on to the next. For “Level 1” we will be exploring the effects of using various hop varietals, which are known to be higher in precursor compounds, in the whirlpool, to increase thiol production during fermentation. Additionally, we plan to explore the effects of using various varieties known to be high in “free thiols”, in the dry hop, to further understand the unique impacts of hop products on thiol creation in IPA. So “Level 1” is all about hops, specifically varietal distinction and how their natural variations affect the types of flavors produced by thiolized fermentation.

We have a rough road map for future “Levels”, other parameters that we aim to play with are the use of different base grains, extract products created from high-precursor and high free-thiol hops, current and emerging products from our friends at Phantasm NZ and really anything else that emerges in the process. As tends to be the case with true scientific experimentation, we are going to start out with a structure that makes sense and maintain an open mind to testing new pathways as they emerge. The overarching goal of this series is to further understand the individual impact of each piece of the puzzle so that we can further refine our production of these unique beers.

This is a series that will grow and evolve as time goes on, with each level incorporating lessons learned from the prior ones. As such, we expect each level to take longer to explore than the last as the ingredients, processes and permutations stack on top of each other, taking us down new pathways at each turn.

We’re pretty stoked about this series, being the nerds that we are, it’s always exciting to endeavor down new roads and discover new possibilities. We hope that you’ll enjoy the ride with us as we adventure into the mysterious world of thiolized IPA.