Author: Marshall Schott
Fermentation temperature interests me. For years, I was guided by the idea that cooler fermentations decreased the risk of off-flavor production and ultimately produced better beer. While the first ferm temp xBm using a hybrid strain seemed to discredit this idea, the second trial using an English ale yeast offered some confirmation. As a lover of lager beer, I was naturally curious how different a beer pitched with a traditional lager strain might taste when fermented at a temperature far outside the manufacturer’s recommendation. Naturally and with only slight trepidation, I designed an xBmt I felt would certainly would produce interesting results.
| PURPOSE |
To investigate the qualitative differences of 2 beers made from the same wort, pitched with the same amount of the same yeast, and fermented at temperatures 16°F apart from each other.
| METHOD |
I chose to brew a Bohemian Pilsner for this xBmt not only because it’s a delicious style, but I participate in a quarterly local competition and this was the prescribed style due at the time.
Bohemian Pilsner Recipe
| Batch Size | Boil Time | IBU | SRM | OG | FG | ABV |
| 11 gal | 60 min | 38.8 | 3.3 | 1.049 | 1.008 | 5.4 % |
Fermentables
| Name | Amount | % |
| Belgian Pils Malt | 17 lbs | 92% |
| CaraPils | 1.5 lbs | 8% |
Hops
| Name | Amt/IBU | Time | Use | Form | Alpha % |
| Magnum | ~28 IBU | 60 min | Boil | Pellet | 12.2% |
| Czech Saaz | 60 g/7 IBU | 30 min | Boil | Pellet | 3% |
| Czech Saaz | 60 g/2.7 IBU | 10 min | Boil | Pellet | 3% |
| Czech Saaz | 60 g/1.1 IBU | Flameout | Boil | Pellet | 3% |
Yeast
| Name | Lab | Attenuation | Ferm Temp |
| WLP800 Pilsner Lager Yeast | White Labs | 84% | 50°F & 66°F |
I picked up a fresh vial of WLP800 Pilsner Lager Yeast and threw it into a large starter a few days ahead of time, which I would later split evenly between each batch.
The night prior to brew day, I milled the grains and collected all my water.
It’s always good to have a willing deckhand around.
The next morning, I awoke to Minus The Bear’s Listing, hit the flame on my strike water, started a pot of coffee, and was mashed in before 5AM.
Utilizing Martin Brungard’s fantastic Bru’n Water spreadsheet, I was able to reach my target pH of 5.3 using gypsum, calcium chloride, and a touch of lactic acid.
After a 1 hour mash, I collected the sweet wort, nearly filling my 15 gallon kettle, using FermCap-S to avoid one of the most annoying of brew day incidences– the boilover.
You’d probably never guess, but I question the necessity of boiling wort longer than 60 minutes, even when it’s made from mostly Pils malt (xBmt planned). After an hour of boiling, I chilled the entire volume of wort to 65°F (18°F) with my Hydra IC, racked equal amounts to separate 6 gallon PET carboys, then placed each in a different fermentation chamber, one set to 66°F (19°C) and the other set to 50°F (10°C). I had to wait 6 hours for the cool fermentation batch to chill completely before pitching the yeast into each batch.
At 6 hours post-pitch, the cool ferment beer looked predictably unchanged, while the warm ferment beer was starting to show signs of activity in the form of white frothy bubbles.
Indeed, I’m becoming a bigger fan of some dry yeasts lately, though something I appreciate about liquid yeasts propagated in starters is the reduced lag time. Just 24 hours in and both beers were chugging along nicely.
I used a modified version of the quick lager method for these beers, extending the time left at target fermentation temps by about 4 days. I took an initial hydrometer reading 8 days post-pitch and found the SG of the cool ferment beer was much higher than that of the warm ferment batch, which wasn’t unexpected.
At this point, I began gently ramping the temperature of the cool ferment batch. It took approximately 2.5 days for it to reach the same 66°F (19°C) as the warm ferment batch.
Another 4 days and both beers were sitting near the target finishing SG.
I waited another 4 days before confirming the FGs remained the same, after which I cold crashed, fined with gelatin, and kegged.
The beers were clear, carbonated, and, in my opinion, rather tasty by the following weekend.
| RESULTS |
I allowed these beers to sit in my cool keezer to lager for nearly 3 weeks before presenting them to participants, as my plan was to collect data for this xBmt during the 2015 National Homebrewers Conference. When it came time to prepare the beers for travel, I bottled from my tap using the now defunct (sadly) Bowie Bottler into 22 oz bottles and kept them chilled at all times. On the morning of the first day of the NHC, I sent out a message inviting interested folks to meet me in the lobby for some tasting… if you tweet it, they will come.
Later that day, a live tasting was performed for Basic Brewing Radio in my room where another 8 people completed the evaluation.
The next day, I setup tasting stations during the AHA Forum meet-up, which Malcolm helped manage, and another group of great people contributed their palates to the cause.
The response was overwhelmingly positive and the cast of participants was truly incredible. Thank you all so much for your help!
In all, a whopping 39 conference goers participated in this xBmt including certified BJCP judges, provisional judges, experienced craft beer drinkers, and homebrewers. Each participant was blindly presented 3 samples, 2 from the warm ferment batch and 1 from the cool ferment batch, then asked to select the one they experienced as being different. While 19 (p<0.05) accurate responses would be required to achieve statistical significance, only 13 tasters accurately selected the cool ferment beer as being different. These results suggest any impact a 66°F fermentation temperature had on the beer was difficult to distinguish for a rather hefty majority of participants.
Since I started doing these xBmts, more than a few people have suggested we might see more significant results if the participant pool consisted of only “trained tasters,” opining a panel of certified BJCP judges might produce more valid data. I typically respond that we’re not interested in what only trained tasters perceive, though even if we were, it would be logistically very difficult to get a large enough sample size to produce any meaningful information. Unless, of course, data is collected at an event chock-full of these masterful palates. For no other reason than to satiate curiosity, I decided to parse out the responses of the 19 certified BJCP judges who participated in the xBmt, a sample size similar to what we are usually able to achieve. In order to reach statistical significance, 11 judges (p<0.05) would have had to select the different beer. Only 7 were capable of doing so.
Just like with the non-judge tasters, the responses of the certified BJCP judges were consistent with chance. Certified BJCP judges were correct 36.8% of the time while non-judges were correct 30% of the time, a difference that may seem significant, but statistically it’s not. To me, this seems to suggest a similar capacity to distinguish differences regardless of whether one is a judge or not. But who am I to say?
Since significance was not reached in this xBmt, the comparative data from even the 13 correct participants is moot, so please take the following information with a gigantic grain of salt.
In regards to the aroma, flavor, and mouthfeel characteristics of the beers, opinions regarding similarity were hugely inconsistent, with most tasters endorsing each sample as being somewhat similar to the other. While an insignificant majority or those who were correct on the triangle test reported preferring the aroma of the cool ferment beer, preference for flavor and mouthfeel were evenly split. Overall, 9 of the 13 participants who were accurate on the triangle test endorsed the cool ferment beer as being the most preferred. The nature of the xBmt was then revealed and participants were asked to select the sample they believed was fermented at a traditional lager temperature– 6 chose the correct beer.
My Impressions: I’m not ashamed to admit I was rooting for the cool ferment beer to not only be noticeably different than the warm ferment batch, but better overall. I began sampling the beers a couple days after kegging and was utterly floored at how similar they were. Even with full awareness of the nature of the xBmt and knowing which beers were in the glasses, I could barely determine any differences. I didn’t even have to pretend to suspend bias, they were that fucking close.
| DISCUSSION |
This one got me, it got me real good. Of 3 fermentation temperature xBmts, the 1 furthest from statistical significance not only used a traditional lager strain but had the largest temperature differential (16°F/9°C). If you had told me last month that a Bohemian Pilsner could be fermented with a lager strain at 66°F and come out tasting at least nearly identical to a more conventionally fermented version, I would have arrogantly laughed in your face, accused you of being an annoying ass, then questioned the reason for your website… I mean… anyway, I wouldn’t have believed you. I’m primarily a lager beer brewer, I’ve read more about the methods and techniques for making lagers than pretty much anything else, and there’s no way a good Pils could be produced fermented at ale temps. Uh-uh!
Yet here I sit today, data in front me be, jaw slightly agape. What the hell are we to make of this? Should I start fermenting all of my traditional lager beers at ale temps? I don’t think so. After all, as we rarely fail to point out, this is but a single point of data involving a beer produced under relatively well controlled conditions using a particular list of ingredients. It’s totally possible a different strain used in a different wort would produce more noticeable differences.
I’ve never claimed to be an expert on anything, I’m just annoyingly curious and like to test shit out. While I’ve no good answer for why these beers were so similar, I couldn’t help but ponder some potential explanations. I’ve heard/read higher pitch rates tend to suppress ester and phenol production thereby producing a cleaner beer; maybe the lager pitch rate for the warm ferment batch had something to do with its clean character. Another idea has to do with a concept I think about often, that commercial brewing practices don’t always apply to homebrewing. As homebrewers, we ferment relatively small volumes of beer under significantly less pressure than the pros, it’s possible these conditions simply require less attention to temperature. Then again, this goes against information I recently read about some commercial breweries turning around huge batches of lager in 10 days when fermented under 1-2 bars of pressure (14-30 psi).
I’m not ready to recommend people start fermenting their traditional lager beers any warmer than they currently do… unless you’ve an experimental bent and don’t mind risking a lost batch, then be my guest! While I certainly don’t plan to adopt this approach (yet), I look forward to continuing this exploration of fermentation temperature using different lager and ale strains.
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63 thoughts on “exBEERiment | Fermentation Temperature: WLP800 Pilsner Lager Yeast In A Czech Premium Pale Lager”
ummmm… ummmm… ummmm… no words! Great experiment. That one was crazy!
I agree. Great exbeeriment!
It seems like — if you use a large and healthy amount of yeast, and a controlled fermentation temperature — you will, with some yeast strains, end up with a nice beer even at a warmer temperature.
I’ve just pitched WLP830 at 28 degrees Celsius so see how it pans out
good experiment! I’d be interested to see how different it would be in lagers that aren’t as hoppy.
This one wasn’t all that hoppy, at least I didn’t think so. I definitely have plans to repeat this one using different lager strains as well, I’ll probably stick with more malt-forward styles. Cheers!
Awesome, cool write up Marshall..
I’ve been shying away from Lager yeasts due to having no fermentation chamber and the ambient temp of my basement is 68-70 even in the winter so I’m limited to wet towel wraps. I might have to stop worrying about that and go for it (RDWHAHB instead).
Hell, maybe I’ll cancel my plans to build/buy/piece-together a fermentation chamber and just keep throwing fermenters in the downstairs bath tub 😉 🙂 (Just kidding — but I will sweat it out less until I do that).
Hey Marshall – your comment on pressure got me thinking: how about an xBm on fermenting under pressure with a spunding valve setup in a corny keg? Curious to know how much that would really speed up lagers on the home brew scale. Would sacrificing serving keg capacity as well as smaller fermentation volume (4.5ish gal for headspace i hear) pay dividens in being able to crank out lagers even faster …. hmmm I wonder. My guess is, you already have this one on the list 🙂
Hey Ryan! Haven’t done it on lager yet, but: https://brulosophy.com/2015/04/27/under-pressure-the-impact-of-higher-psi-fermentations-exbeeriment-results-2/
Nice read! Definitely would like to see the results using traditional lager strains.
Brilliant stuff. The more of your xBmts I read about, the more I cringe at the thought of the advice I’ve passed on to other brewers on forums – most of it just baseless regurgitated hearsay.
The last beer I made was a helles lager split into three batches and brewed with WLP800, W34/70, and Nottingham, all at about 12 Celsius. The WLP800 produced a lovely continental lager with a slightly spicy but smooth character reminiscent of Kolsch (WLP029). But what really blew me away was how similar Nottingham and W34/70 were – I couldn’t tell the difference at all. Neither as good or as lager-like as WLP800 or Kolsch yeast and they both had a slightly cidery tartness. If you’re going to try comparing lager yeasts, I’d suggest throwing in WLP029 and Nottingham and see who can spot the ales..
See below – WLP800 is probably a cold-adapted ale yeast like the kolsch family, rather than a true lager yeast.
Also, dry Nottingham is allegedly 70% “lager” yeast. Edd Draper found at least two strains in Nottingham, but neither behave like a true lager yeast so it may be a cold-adapted ale yeast. But it could be a Frohberg lager yeast like 34/70 – or (one assumes) Danstar Diamond Lager…
It seems possible that the most important thing to keep yeast from throwing off flavors is to keep the ferm temp steady throughout the first few days of fermentation – even if that temp is much higher than what is typically used for a particular style or yeast.
Another great exbeeriment! Looks like I’m not going to have till fall/winter to brew some lagers. I currently ferment in my basement that maintains a 65ish temp during the summer. Lately I have also been keeping my fermenter in tubs of water to keep the temps steady, but I have not been adding ice to them. Going to give this a try!
Awesome as usual. I’ve shied away from lagers thus far, but have your quick-lagering method on my brew calendar this fall. Keep up the good work. Oh, and sweet t-shirts. Can’t wait to get mine next month!
Hi Marshal,
Great idea you’ve had. Probably many of us thought about this but… never done it.
One thing: if this exbeeriment is really reproducible… forget lager versus ale fermentation schedule (not yeast) history in homebrew… and forget Narziss/Tasty/Brulosopher lager fermentation temperatures???
I must take the courage and give it a try ;)))
Confirming more of what some of us already knew. Glad to see the experiments.
Nice stuff. I would be interested to see like, what happens to continued generations of these yeasts. What might “hot lager gen 4” be like compared to its “cool lager” sibling? Maybe the homebrew bias is based on industry bias, but isn’t as applicable because homebrewers typically use lab-fresh yeast?
I have to agree with the idea that the quantity and quality of the yeast pitched into the wort made the temperature less important. My understanding of the way lagering started, back when there was little control or understanding of yeast, was by keeping the temperature down only the larger yeast strains were able to be active so you got the characteristics from those strains. However, since the yeast is so well controlled and you put such a large active pitch into the wort my guess is it was able to overpower any other yeast keeping the off flavors out. It would be interesting to reach out to white labs with your results to see why they have the temperature guidelines set to between 50-55 and what they worry about at higher temperatures, if it is stressed yeast or cross contamination of yeast strains.
This is similar to the theories I’ve read, makes sense to me.
Maybe I’m blind but I didn’t see what your pitch rate actually was??
It’s whatever my preferred calculator told me it should be for a lager given the manufacture date and OG.
OK thanks – I wonder how your results might vary if you used an Ale pitching rate – like people have mentioned, a big healthy yeast pitch might be playing a part here.
Awesome . As I would like to be your neighbor…
I have a question about the starter size. Yeast calculator says for a 11 gal batch of lager beer we need 759 billions of cells. If we start from a excellent viability bial of white labs ( 100 bilions). We will do 12 -13 litres of wort or stepping starter. In the exberriment photos I only see one erlenmeyer. How do yo calculate it? Maybe select hybrid fermentation?
Thanks and congratulations for your blog and the exberriments
Using the HomebrewDad calculator, best by date minus 4 months, my brew date, and a 5L flask, I get that I’ll need ~720 billion cells, which will take a 4.5L starter of 1.040 wort. That’s what I did, then split it evenly. It was a very fresh vial– best by of 7/2, brewed early April.
Thanks for the kind words, cheers!
Thanks for your quick response. I just discovered the problem for this big difference of billion cels. It’s very diferent choose stir plate Jamil Zainesheff than stir plate K.Troester.( similar to homebrewdad)
But, I have difficulty to understanding how two supposedly valid methods have so large differences in the final number of cells ( approximately 300 billions).
Cheers!!
I figured you might have been using Mr. Malty, which I’ve accepted is somewhat outdated… only because Kai’s calculations have been working for me for over 4 years now. Cheers!
After reading through a bunch of your experiments, I’m starting to think that one thing that might be vital is CONSISTENT temperature. Perhaps its much more important to avoid wide day/night temperature swings than to hit a certain temperature.
Perhaps it is… 🙂
New xBmt maybe? 🙂
🙂
What was the ph of the final beers ?
I’ve never measured the final pH of a non-sour beer, I’m not sure.
If you can degass them and warm them up to room temp you can provide a data point to indicate if the theory about ph dropping more the faster the fermentation went is correct. Your using the same wort and yeast but one fermented much faster than the other. Perfect test case !
Huh, I’ve never heard that theory. I’ll definitely check this out at some point!
I’m sorry if the answer to this is painfully obvious in your article, but I want to be certain I am understanding perfectly…The warm lager was essentially left at 66 degrees the whole fermentation time and then finally cold-crashed? That is how I read this. Am I correct, or did you only start it at 66 degrees, and then move on to a modified quick lager for both batches? Thank you for this article.
The warm batch was at 66F for about 7 days, then ramped to 72F for another week or so, crashed, fined with gelatin, and kegged.
Did you pick the 7 day mark arbitrarily or did you time it with when you hit 50% attenuation? I’m 2 days in on my pils using larger yeast slurry from a local brewery and wondering if I should bump up the temp based off of attenuation or days. Thanks!
It was past 50% by day 7, by a hair.
If we believe, which I do at least in part, that most of the esters and phenols in beer are generated during the yeast multiplication phase and we keep it to a minimum by pitching the “lager” pitching rate (around double the usual ale pitching rate) this might explain the reason for the minimum changes between batches. I would like to see what’d had been the result if the warm fermented beer had been pitched Ale rates but I will try this for sure in my next Helles. Worst case scenario I will have 5 gallons of Helles and five gallons of Cream Ale…
Cheers!
It’s in the list (with a different yeast)!
Man. WTF? Foundation officially shaken.
Nice work.
Hi, thanks for this great xbmt ! I have a question concerning this yeast, WLP800; is it more suited to lower temperatures than W-34/70 ? Could you notice any difference between them ? I am going to ferment my lager cold and lager at 1-2°C starting from 50% attenuation, to obtain saturation of C02 in the lagered beer (natural carbonation/lagering). I wonder if I can use W-34/70, or if a bohemian yeast is better suited to do that ?
We’ve plans to play with 34/70 very soon, but in my anecdotal experience, both are suited well for lower temps.
Fine, thanks a lot for the answer Marshall. I was especially wondering about the difference between Saaz and Frohberg bottom fermenting yeasts (if you heard about these 2 groups) in homebrew setup. Since W-34/70 is the Frohberg exemple, I thought comparing it with a Saaz exemple which I believe WLP800 is (if it is actually originating in Pilsen as WL says). Anyway, looking forward to those tests with W-34/70 !!! 😉
See below – WLP800 is probably an ale yeast, so not a Saaz lager yeast like one might expect. WLP862 definitely is a eubayanus hybrid, per the Borneman paper.
Just wanted to thank you for the great article. Gave me the courage to attempt my first lager (been doing ales for years). WLP830 Worked great fermenting in low to mid 60s and tastes fantastic, super clean and no off flavors at all. Thanks for opening my horizons and dispelling those myths about how lagers have to be made.
I just did a split batch of bopils with WLP800/WY2124 last night. This was pitched at 62F and sitting in a swamp cooler in my basement that sits at that same temperature, so these should stay consistent.
I’ll post back with results, but this article gave me the guts to do it!
Regards,
Justin
Looking forward to hearing how it turns out for you!
Yes cool xBmt, which confirms a few things for me. I had recently done most my lagers under pressure and at 15 C, then raised them. I am now experimenting with 20 C batches under pressure and i am super surprised how good and clean they are. Thanks for another good read!
Hahahaha great! I’m interested trying this out 🙂
which dry lager yeast would you recommend for a beginner? (something very clean if possible)
cheers!
Saflager W-34/70 works great!
You rock! Thanks 🙂
Following your advice, I brewed 30 gallons with W-34/70, fermented at 61 F. The beer is super clean! Thanks gain for those useful experiments! 🙂
I thought there was a statistically high proportion of twins at this tasting…until I realised there was a mirror in the room. D’oh!
Ha!
Hi Marshall, nice work! What was the mash temperature? Thanks 🙂
So Marshal – the big question is, when you ferment lagers now, do you opt for a traditional lager yeast at a cool temperature, hybrid yeast at a cool temperature or lager yeast at a warm temperature?
Traditional lager yeast at ale temps, for the most part.
Guys, it’s probably worth noting that Borneman et al doi:10.1534/g3.115.025692 sequenced WLP800 – but didn’t have it in Figure 3, their list of “inter-specific hybrids…strains that contained at least a 10% contribution from at least one chromosome from a non-S. cerevisiae”.
***The implication is that WLP800 isn’t a true (hybrid) lager yeast but a kolschy, cold-adapted ale yeast.***
That may explain some of these results. The more people sequence yeast the more ale yeasts they find in lager breweries, but it’s a bit of a surprise to find one in Urquell. Might be something to do with the open fermenters they used until quite recently.
Like qq said, WLP800 is a pure Saccharomyces cerevisiae “ale” yeast strain from recent DNA sequence and studies done in Australia. I have personally fermented great lagers right in my living room at 73 F using a special hybrid mix of S-189, S-23 and Voss Kveik as my starter. Tastes wonderful!