At Fermentis, we’re very excited to have launched SafLager™ SH-45: the ideal yeast for increasing hop thiol release in lagers. This strain was selected for its impressive ability to release and partially esterify thiols precursors found in hops. As a result, beers crafted with SafLager™ SH-45 present enhanced passion fruit aromas and intensified citrus and tropical notes.
The latest addition to our lager range, SafLager™ SH-45 is a Saccharomyces pastorianus yeast strain, an interspecies hybrid of S. cerevisiae and S. eubayanus. This natural hybridization gives Saccharomyces pastorianus strains the ability to ferment at lower temperatures, be maltotriose positive, POF negative, and have fast sedimentation.
Compared to the existing lager yeasts in our range, SafLager™ SH-45 has a medium fruity/estery aromatic profile. What makes this strain stand out is its remarkable ability for biotransformation with thiols.
Initial trials
Our initial laboratory trials using standard conditions (identical to our baseline trials: original gravity 15°P, fermentation temperature 14 °C, pitching rate 100g/hl) demonstrated that SafLager™ SH-45 has:
- An average fermentation speed and finishes at the same time as other strains in the SafLager™ range (day 8/9)
- Average attenuation (ADF) compared to other strains – exactly what you would expect for a lager (80-84% with 100% malted barley).
- isoamyl acetate ester production slightly above average, but lower than SafLager™ E-30.
This is a nice level of ester production during fermentation for a lager beer, but what makes SafLager™ SH-45 so perfect for hop-forward lagers is what happens next…
Biotransformation
A growing trend in brewing, biotransformation occurs when yeast-derived enzymes convert odorless and flavorless precursors into desirable flavors and aromas. Certain yeasts, like SafLager™ SH-45, facilitate hop biotransformation, which unlocks new aromas that hops can’t achieve on their own during fermentation.
There are two families of compounds in hops that can be released – thiols (more fruity) and terpenes (more floral). Precursors in the hops are linked to another compound: cysteine (cys-thiol or cys-adduct) or glutathione (G-thiol or GSH-adduct). GSH-thiols are much more present in hops than cys-thiols. When linked or bound, these precursors are unperceivable. Certain yeasts, however, like SafLager™ SH-45, have the ability to break these links coming from GSH-adducts and set free the thiols, producing desirable flavors and aromas in the beer. In addition, and remarkably, SafLager™ SH-45 has a good ability to esterify these freed thiols into volatiles that are even more aromatic.
Laboratory trials
To gain a better understanding of SafLager™ SH-45 biotransformation capabilities, lab trials were conducted with synthetic thiols. Cyc-adduct and GSH-adduct precursors were fermented using different Fermentis yeasts in unhopped wort under various conditions to compare the thiol extraction and concentration.
SafLager™ SH-45 showed a remarkably higher potential to release bound thiols and esterify the alcoholic form from GSH precursors. SafLager™ SH-45 released the highest amount of 3SHol (3MH) and 3SHA (3MHA) esters from GSH-thiols.
Hop to it!
So, for the best results, which hops should brewers be using?
It’s well known in the hop industry that Citra has more free thiols than other varieties. This makes it a popular choice for brewers looking to create hop-forward beers. Hallertau Blanc also contains free 3SHA (3MHA).
When it comes to precursors (G-3SHol/3MH), all hops tested in our trial had promising potential, notably Polaris, Citra, Hallerteau Blanc and Amarillo.
Based on these results, it’s possible to calculate the maximum amount of free and released thiols you can expect from hops. As shown in the graphs below, Citra is already releasing a lot of 3SHA (3MHA); however, SafLager™ SH-45 also unlocks a significant amount of this compound. With Hallertau Blanc, most of the thiols come from SafLager™ SH-45 biotransformation. Amarillo has less free thiols, but even with less precursors, our results show that there is good potential for biotransformation with SafLager™ SH-45.
Brewery trials
In our pilot brewery trials, we experimented with dry hopping during fermentation to allow direct contact between the hops and the yeast. This brew was dry hopped equally with Citra, Amarillo, and Hallertau Blanc at a dosage rate of 200g/hL in the kettle, 15 mins before the end of boil, then again at 200g/hL on the second day of fermentation. SafLager™ SH-45 produces a fresh lager, with notable citrus and tropical flavors coming from the hops, as well as a perceptible thiolic character (sauvignon/green vegetal).
Key takeaways
For brewers looking to create hop-forward lagers, SafLager™ SH-45 is an ideal solution. It presents high thiol esterification activity, particularly from glutathionylated (GSH) precursors.
When compared with the existing strains in our SafLager™ range, SafLager™ SH-45 shows an average fermentation speed and an average attenuation. It ferments well at 14°C and produces a medium fruity/estery character. What sets SafLager™ SH-45 apart is its impressive ability to release free thiols from GSH precursors.
This presents a key advantage for brewers: when it comes to desirable hoppy flavors, SafLager™ SH-45 gives brewers a greater return on their investment. Its ability to release thiols means that brewers can use less hops for the same effect or more.
We’re excited to share more results with you soon!
So, what are you waiting for?
SafLager™ SH-45 is available in 11.5g, 100g, 500, 2.5kg and 10kg formats. For more information about this strain, visit: our product page or contact your local distributor.
For more technical information on our trials, check out our live recording on SafLager™ SH-45 with Gilles Goemaere, our Technical Sales Support Manager for Beer Europe.
You can also watch our Brewer Story from Amelia, Italy. The team at Birrificio Amerino used SafLager™ SH-45 to brew a hoppy lager bursting with fruity flavor.
