Scientifically-driven Hoppy Lager Designed to Push Fruity Hop Thiols
ne of the reasons I love grinding through academic brewing papers is because sometimes findings from multiple studies can come together and inspire something new for me to try. This happens organically as I go down rabbit holes on unrelated topics and start connecting the dots. The great part about writing for the blog and my book is that it forces me to not only read the studies but try to explain them to others and think more broadly about how the results might be put into practice by brewers. This is exactly what happened when I was researching hop thiols for a chapter in the book. Looking at the findings from multiple papers, I suggested it might be worth experimenting with a hoppy lager with a dash of wine yeast for multiple science-based reasons, which this post explores. Since I suggested the experiment in the book, I thought I better take my own advice and give it a shot! Before getting into it, I first need to thank my good friend Spencer Love for helping me out with this batch, hopefully, we can team up on a few more brews for articles like this!
I have to admit something though. I’m not the biggest fan of lagers. It’s kind of a running joke at Sapwood if somebody brings in a lager (or something with lactose) it goes to Mike automatically. In fact, we just brewed our first lager at Sapwood, which doubled my career lager brew count total to two batches. Don’t get me wrong, I totally get the appeal for a well-brewed pilsner, for example. But, I’d always rather have something with hops, it’s just who I am : ) I even joked for a while that I wasn’t even going to mention the word lager in the book, but then the research had to spoil it for me as I got too excited about the potential for the lager brewed for this post, which is now appropriately named Thiol Driver.
What’s in this post? First I go through some of the research that inspired this particular brew, which will explain why the recipe was crafted as it was. Then the recipe and tasting notes for Thiol Driver follow the science discussion. Spoiler, it’s pretty good!
The Hop-Derived Ester 2MIB
Although studied slightly less in the literature, various esters from hops can impact final beer flavors and aromas just like hop thiols and terpenoids. One of the hop-derived esters that’s gotten some attention is 2MIB (2-methylbutyl isobutyrate) because of its ability to give a beer apricot-like flavors. 1
So, which hop varieties have more of this particular ester? One paper brewed single-hopped beers in order to determine final 2MIB concentrations for different hop varieties used in the whirlpool. Only Southern Cross tested above the threshold (which is 78 ug/L). Other varieties that were below the threshold, but still had relatively high levels of 2MIB, were (in order from highest) Pacific Jade, Polaris, Huell Melon, Riwaka, and Waimea and could all be other varieties to play with for late hopping if trying to push the apricot-like ester.2
Yeast strains may also play a role in the final hop-derived ester concentrations, as one study looked at 2MIB in ale and lager fermentations. The results showed that a Pilsner fermented with a “standard lager yeast strain,” resulted in more 2MIB than the ale, which was fermented with an English strain. Although the increase wasn’t massive, the beers had the same dry hopping and the lager strain resulted in approximately a 17% 2MIB increase.3 This is exactly why I chose to ferment Thiol Driver with a standard lager yeast (S-23 SafLager German Lager).
A 2018 BrewingScience paper also looked at the role of two different yeast strains (WLP001 California Ale and WLP029 German Ale/Kolsch) and the concentrations of terpenes, esters, and thiols paired with early fermentation dry hopping. They dry hopped with either Cascade or Hallertau Mittelfrüh on day three of fermentation and then tested the beer for its compounds. The Kolsch strain in the study outperformed the ale strain in final 2MIB concentrations, which suggests it may also be a strain worth trying in a beer like this to push 2MIB.4 I would love to see follow-up testing with the lager strain used in Thiol Driver!
Synergy Between Hop Esters and Thiols
The synergy between compounds is another area of exciting hop research, particularly because researchers are finding that hop thiols can actually lower the taste threshold of fruity terpenoids. One such paper looking specifically at Nelson Sauvin, which is unique in that it’s rich in the thiol 3-sulfanyl-4-methylpentan-1-ol (3S4MP). The authors tested the possible synergistic impact of the thiol when dosed with other known hop compounds. Specifically, a solution with 40 ng/L (the threshold) of 3S4MP was compared to solutions with the same amount of 3S4MP in addition to other compounds (linalool, 2MIB, and geraniol), some below their thresholds.
Focusing on the paper’s findings as it relates to 2MIB, the authors found that the presence of the Nelson Sauvin thiol (3S4MP) actually enhanced the flavors of 2MIB, even though 2MIB was dosed below the threshold.5 This enhancement of flavor via synergy is interesting because it suggests that 3S4MP is acting as a flavor enhancer to 2MIB, boosting its flavor potential above the actual concentration.
The findings above are why Thiol Driver is hopped with Southern Cross in the whirlpool, potentially pushing the apricot-like 2MIB ester close to or above its taste threshold. Thiol Driver is then dry-hopped twice with Nelson Sauvin to impart its unique 3S4MP thiol which should even further push the sensory experience of 2MIB!
Thiols and Fermentation Temperature
Although I go into much more detail regarding hop thiols and biotransformation in the book, here are the main three hop-derived thiols studied with their descriptors:
- 4MMP – Boxtree, ribes, and blackcurrants.
- 3MH – Grapefruit and gooseberry.
- 3MHA – Passion fruit and guava. 3MHA is converted from 3MH during fermentation with the right yeast strain that has been tested to produce β-lyase during fermentation. A commercial enzyme can also be used with normal ale strains (like Rapidase Expression Aroma).
Now, what’s of most interest to me regarding thiols and using a lager strain (in addition to the potential for more 2MIB) is a finding that lower fermentation temperatures may help to raise final hop thiol concentrations. Remember that lagers ferment at lower temperatures than ale strains. A paper that examined whether thiol concentrations increase or decrease based on fermentation temperature dosed test beers with Mosaic hops at the onset of fermentation (early dry hopping) and measured thiols 3MH and 3MHA. The authors found that almost twice the amount of 3MHA was measured in the beer fermented at 59°F (15°C) compared to the one at 71°F (21°C) with a wheat beer yeast (Tum 68).6
Specifically, the above paper found that the tropical and desirable 3MHA (which is converted from 3MH) went from 4 ng/l to 8 ng/l at the lower temperature. This might not seem like much, but with a low threshold for 3MHA (9 ng/l), you can see why it’s important. Also, because 3MHA is converted from 3MH, it’s equally important that the 3MH concentration also increased when fermented at the cooler temperature going from 31 ng/l to 37 ng/l. Obviously, the more you can push the 3MH the more potential for 3MHA (especially with the right yeast strain or with a commercial enzyme). The passionfruit leaning 3MHA thiol is one that I’m most excited about, so anything I can do to set the stage for it’s production I’m interested in trying.
The results above can be somewhat explained by a 2011 paper focusing on the aroma compounds in wheat beer when injected with CO2 at different temperatures (mimicking fermentation). The authors found that the polarity of the compounds played a role in the potential loss during fermentation. The more hydrophilic a compound, the more likely it will remain in the solution during fermentation and be less impacted by temperature increases.7 This makes sense as studies have shown that in beer and wine must fermentations volatile compounds are partly transported to the surface by CO2 and released into the gas phase. Because thiols have lower boiling points and are less soluble than other solvents like alcohols, you can see why they may be more impacted by increased fermentation temperatures.
Wine Yeast and Bioflavoring (VIN 7)
Ok, so if using a lager strain we might be able to push 2MIB levels (especially with Southern Cross in the whirlpool), dry-hopping with Nelson Sauvin might synergistically increase the perception of 2MIB, and fermenting at the cooler lager temperature might increase thiol concentration like 3MH, how can we try to increase the conversion to 3MHA? Enter wine yeast and their magical abilities to bioconvert! I’ve leaned heavily on wine research in this area of biotransformation of thiols because they have been looking at the topic for some time. Many of these same thiols we are interested in studying in hops are the same ones they are looking at in wines (mostly white wines).
One such study examined seven wine strains for their ability to release volatile thiols, including strains L2056, NTII6, VIN7, VIN13, VL3, X5, and QA23. The results showed that VIN7 released the second most 3MH and had the highest concentration of 3MHA, which was converted from 3MH.8 So I think we have our winner for Thiol Driver, I used just 8% VIN7 as part of a yeast blend with the lager strain, which is easy to do with dry yeast as you can just measure out the blend in grams. So now we are taking advantage of the cooler lager fermentation temperature for thiol retention and hopefully getting a greater release of thiols with the wine yeast, which also happens to work best at the cooler lager temperatures.
I purchased VIN 7 from Scott Laboratories (no association with me, this cracked me up at a recent conference, two people thought Scott Laboratories was a side project of mine). The problem is that it comes in 500-gram bricks, which is fine for me as I can put it to work at Sapwood, but homebrewers don’t need this much. You could get a brick as part of a homebrewer club and split it up amongst the members if it’s something you want to experiment with.
Here is the commercial description of VIN 7 :
“Ideal for the production of aromatic white wines at low temperatures. VIN 7 releases passion fruit, grapefruit, gooseberry and guava aromas and flavors from their non-aromatic precursors in the must. It is therefore especially recommended for vinification of the following grape varieties: Sauvignon blanc, Chenin blanc and Colombard.”
VIN 7 Specifics:
Temperature range: 13-16°C (55-61°F)
Glycerol production: 5 – 7 g/l (medium range)
Thiol Driver Recipe
Brewed: July 2019
|OG/FG/ABV||Est. IBU||SRM||Water||Mash Temp.|
|1.046/1.019/3.5%||42||4.3||10 gallons reverse osmosis water (38 L). Treated with 8 grams gypsum, 3 grams Calcium Chloride, 1 gram table salt, 2.2 grams Epsom salt (whirlpool). Overall water profile: RO Water
Ca:75 Mg:6 So4:150 Na:10 Cl:50
|Pilsner Malt (1.7 SRM)||76%|
|Golden Naked Oats (10 SRM)||8%|
|Soft Red Wheat Flakes (1.6 SRM)||8%|
|Flaked Rye (2.0 SRM)||4%|
|Columbus||23 grams||Mash Hop (pre-pH adjustment)|
|Columbus||5 grams||60 Minutes|
|Southern Cross||73 grams||15 Minute Whirlpool (at flameout)|
|Nelson Sauvin||57 grams||Day 14|
|Nelson Sauvin||85 grams||Day 17|
|1g VIN 7 11.5g S-23 (SafLager German Lager)||55°F (13°C)||60°F (16°C) After a week.|
Appearance: Beautiful light hazy gold. Tight, firm head with excellent retention and lacing.
Nose: Bitter gooseberry, pine, peach rings, the jelly inside a donut, crackery pilsner, oddly cinnamon-like when warmer.
Palate: Bright hop front, but not super varietal specific, bold fuzzy stone fruit, grainy pilsner malt, tangy apple skin, mild lingering minerality but really clean, wheaty peach skin, long white wine palate (glycerol?). For the amount of Nelson used, it’s kind of crazy how not Nelsony it is which may be due to some of the bioconversions and synergy pushing the fruitier notes. Super happy with the creaminess of this low ABV lager and how the wine yeast didn’t get too expressive (In previous experiments I’ve gotten some phenolic flavors).
Thoughts/Changes: Drinks really clean and fruity. Pils malt is a tad detracting personally (Spencer doesn’t love pilsner, thinks it can sometimes come across slightly soapy), lacks some complexity. Would potentially swap out for a full pound of malted rye for a deeper character, which might also play well on the back palate drying. There is a noticeable drying Epsom character but it works well. Certainly in no way catty. Drinks best a little warmer than most lagers (40-42 degrees). We went through this 5-gallon (20L) keg pretty quick, it was just so unique in a good way. I encourage people to experiment with this concept and let me know what you think!
- 2MIB (2-methylbutyl isobutyrate) is a hop-derived ester that can contributed apricot-like flavors.
- Southern Cross produced the most 2MIB, but Pacific Jade, Polaris, Huell Melon, Riwaka, and Waimea are other high producers (but under the taste threshold).
- A standard lager yeast strain resulted in more 2MIB than an English ale strain tested.
- The presence of the Nelson Sauvin thiol (3S4MP) enhanced the flavors of 2MIB, even though 2MIB was dosed below the threshold via synergy.
- Some thiols may be retained in higher concentrations with lower fermentation temperatures.
- VIN 7 wine yeast has a strong ability to enhance 3MH (grapefruit) and ultimately 3MHA (passionfruit) flavors.
- Takoi, K.; Tominaga, T.; Degueil, M.; Sakata, D.; Kurihara, T.; Shinkaruk, S.; Nakamura, T.; Maeda, K.; Akiyama, H.; Watari, J.; Bennetau, B. and Dubourdieu, D.: Identification of novel unique flavor compounds derived from Nelson Sauvin hop and development of new product using this hop. Proc. 31st EBC Congr., (2007)
- Takoi, K., Sanekata, A., Itoga, Y., Koie, K., Matsumoto, I., & Nakayama, Y. (2016). Varietal Difference of Hop-Derived Flavour Compounds in Late-Hopped/Dry-Hopped Beers. BrewingScience, 69, 1-7.
- Schmidt, C., & Biendl, M. (2016). Headspace Trap GC-MS analysis of hop aroma compounds in beer. BrewingScience, 69, 9-15.
- Matsche, B., Muñoz, A., Wiesen, E., Schönberger, C., & Krottenthaler, M. (2018). The Influence of Yeast Strains and Hop Varieties on the Aroma of Beer (Vol. 71). BrewingScience.
- Takoi, K., Degueil, M., Shinkaruk, S., Thibon, C., Kurihara, T., Toyoshima, K., Tominaga, T. (2009). Specific Flavor Compounds Derived from Nelson Sauvin Hop and Synergy of these Compounds. BrewingScience, 62, 108-118.
- S. (2011). Volatilization of Aroma Compounds Relevant for Wheat Beer in Water Under Conditions Simulating Alcoholic Fermentation. Journal of the American Society of Brewing Chemists. doi:10.1094/asbcj-2011-0822-01
- S. (2011). Volatilization of Aroma Compounds Relevant for Wheat Beer in Water Under Conditions Simulating Alcoholic Fermentation. Journal of the American Society of Brewing Chemists. doi:10.1094/asbcj-2011-0822-01
- Swiegers, J., Francis, I., Herderich, M., & Pretorius, I. (2006).
Great! I love the thiols topics. First of all, did this taste like a lager at all, or where someone to try it he’d guess it’s a neipa? Secondly, you never mentioned the fg.
Whoops, updated! Thanks! Great super low ABV beer!
Your comment about Lagers struck me as funny because the first thing I tried after reading your book was making adjustments to my Czech Pilsner recipe to help the hop flavors!
I addition to the extra Rye you mentioned, what else would you change if you were to try this again?
Probably substitute some of the pilsner for 2-row.
Are both the wine yeast and lager yeast added at the same time?
Yup, pitched at the same time!
Hey! Great F’ing article! Couple questions for ya.
What percentage of malted rye would you add and would the flaked rye stay at 4%?
If you substituted some Pilsner for 2-Row would they be equal percents?
I have access to QA23 but not the other wine yeasts, would you still use 1g and 8% along with lager yeast?
I’d probably try upping the rye to about 8% (keeping flaked wheat the same) and doing close to a 50/50 split pilsner/2-row. But if you like Pilsner malt, stick with that!
QA23 is another great bioconversion wine strain, but I do believe it’s a killer strain, so that’s something to think about. Hope that helps!
Sorry man but I just wanna double check… you’d just increase the flaked rye to 8% and not substitute in any malted rye? Presumably for base malt that is. I must have misread the article. Guess either/or gets the job done, eh?
Thanks for the QA23 tip!
Sorry Scott but Vin7 is a killer strain positive means that 8% fermented 98%of your beer…92% of lager yeast burned out in few hours…
Most wine yeasts are killer. I’m not 100% sure about this specific one but if it is then the commenter is correct. Your lager yeast was killed off pretty quickly and this beer was fermented almost entirely with the wine yeast.
RE: fermentation temp: even if you ferment in the mid- to high-50s if you then go up to 68+ for a diacetyl rest do you think that has a negative impact on the production/retention of thiols like 3MHA? Or do you avoid elevating temps above the primary fermentation temp in the making of this beer?
My guess would be that since the bulk of the primary fermentation is over at the elevated temperatures, less of the volatiles would be pushed to the headspace.
The passion fruit flavor and aroma didnt came?
Do you think adding more vin7 (15%) at this temperature (13 celcius) could biotransform more 3MHA, without phenolic risk?
Why vin7 and no Alchemy II?
I don’t have access to the VIN7 wine yeast unfortunately but how does the commercial enzyme work? You just add it when you pitch the ale/lager yeast? Have you had success using it? Love your posts and keep up the great work at Sapwood.
Thanks! If you are adding a commercial enzyme, I would consider adding it when you dry hop as they don’t typically like high sugar environments.
I would be really interested in seeing tasting notes of a side-by-side comparison that didn’t have all the thiol maximizing steps taken. It seems hard to say whether or not they made a difference, considering you used a recipe that would taste pretty fruity and hoppy anyway. I’m glad that you did this one, however. I highlighted it in the book as something that I’d like to try
Hi Scott, really enjoying the book and the blog. I think the following yeast might be the same as Vin7 and more readily accessible to Homebrewers – I can certainly get it from a couple of the UK companies:
I’m currently playing around with Co2 extract for hop oils and fruit, I’ve bought some aroma enzyme and I’ve added the above yeast to one beer to date (a wheat beer with a tin of mango puree). The Brulosopher in me would love to do some side by side work as Marco suggests in the comments but yet to have the opportunity. Relying on successive batches at the moment!
Really appreciate your work.
Hey, thanks for getting a copy of the book! I haven’t seen any papers testing the biotransformation potential of BV7, but it seems worth experimentation like in your fruited wheat beer. How did it turn out?
I chucked the whole sachet of wine yeast into the beer (didn’t really consider weighing out quantities to add a lower percentage). It was a little cider like as the mango provided a fair amount of sugar and the beer didn’t have quite enough body to withstand it. No phenolic issues if I remember correctly.
I contacted the company at the time (before it was rebranded as MJ) but they didn’t know if the yeast was a killer stain. Asked me to let them know how I got on!
Considering brewing something similar to your above beer but might try a Kviek yeast as some of the fruit descriptors coming with them are quite unusual. Any experience with them?
Hey Scott, any thoughts on how to calculate the dosing rate for the Rapidase Expression Aroma product from Scott Labs? I am currently working under the theory that the thiols are hop derived and therefore I should be calculating the dosage rate of the weight of hops in the FV. Any thoughts based on your experiences would be super appreciated!
Hey Chris, I don’t have an exact answer for you, but I’ve been dosing ~.5 grams per 5/gallons of beer in my experiments lately.
Perhaps not surprising that WLP029 was good for 2MIB, given that recent sequencing suggests it’s actually a lager strain :
Interesting, I wonder if fermenting with it even cooler might result in even more 2MIB retention.
I can’t get Southern Cross, but I have a load of Polaris and Huell Melon in my freezer (amoing others), do you think a Polaris-Huell Melon-Nelson hop schedule can increase 2MIB above threshold level?
It should get you close! Both have been tested as above-average hops in terms of 2MIB.
We are going to try this. Sounds great. Problem is Scott Labs has a minimum 10lb order for Vin7. Does anyone have 120grams (or I’d buy a brick) available?
I know it’s one of the predominant strains in the Anchor Alchemy blends if that’s easier to get in smaller portions: https://shop.scottlab.com/alchemy-ii-yeast-1kg-015177
Scott,a “basket” of questions:
1. For yeast that have the ability to convert 3MH to 3MHA -do they tend to convert ALL of the 3MH to 3MHA or can you still end up with some of both? Like most people I love 3MHA but I also really like the gooseberry tasting 3MA, so I’m curious if there’s a way to control the amount of conversion and end up with both…. -Is the only major control just the amount of Beta Lyase activity of the particular yeast strain? (If you want both, you have to blend two different base beers and hope that the yeast strain with lots of Beta Lyase is in low enough population or dormant at that stage to not convert any 3MH into 3MHA?
2. For Mash Hop Variety Selection: Is it safe to assume that a given hop varietal’s Free thiol amounts and blends and the same varietal’s Bound Thiols are largely the same? Ex: I see from a 2020 CBC presentation that Citra has about 50% of it’s tested thiols as 4MMP 30% as 3MH, and maybe 10% as 3M4MP, is it safe to assume that the break-out of bound thiols for the same lot of Citra Hops would be about the same or do the bound thiols look completely different for that same hop lot?
(As I think about the flavors I’m looking to get can I safely use the free thiol data that exists and then select my mash hop additions the same as I would whirlpool or active fermentation additions?)
Bonus Question: Any data on what % of bound thiols tend to be cysteine-bound vs. glutathione-bound? (Just curious how much benefit there might be from the 113F protein rest when mash hopping.) -Are there any known yeasts that can convert glutathione-bound Thiols yet?