Impact Of PRESSURE FERMENTATION On A Lager (LAB TESTED!) | exBEERiment

Fermenting lager yeast under pressure is purported to lower ester levels when fermenting at ale temperatures, creating a cleaner tasting beer. To test this out, Martin split a German Helles Exportbier between two fermenters and fermented one at 12 psi while the other stayed at ambient pressure. In addition to serving these beers to a panel of blind tasters, they were also sent into White Labs for objective testing. Are they distinguishable at a qualitative and quantitative level? Let's find out!
RECIPE: share.brewfath...
INGREDIENTS
Epiphany Craft Malt: www.epiphanyma...
Yakima Valley Hops: yakimavalleyhop...
Imperial Yeast: imperialyeast.com/
WHITE LABS:
Mythical Hammer Lager Yeast: www.whitelabs....
White Labs Fermentation Society: www.whitelabs....
EQUIPMENT USED
Clawhammer Supply 240v eBIAB System: www.clawhammer...
Spike Brewing FLEX+: spikebrewing.c...
SUPPORT BRÜLOSOPHY
Patreon: / brulosophy
Affiliate links: brulosophy.com...
CONTACT: [e-mail]

[@Marshall_Brulosophy]

Brülosophy - getting kiddos involved in brewing science since 2014. I’ve been fascinated by the growing popularity of pressurized fermentation, particularly as it relates to lagers. Ferment warm at ambient pressure and you’re committing the worst sin, but add a little pressure and all is good in the world. Not only do the results of this xBmt align with all past results on the same topic, indicating pressure has little perceptible impact, but the lab data objectively shows it doesn’t really do much as well. Ultimately, both beers possessed essentially the same levels of fermentation byproducts, and per the lab data, neither had any that were past flavor thresholds. Fascinating! To me, this further supports the notion that lagers, at least when using certain yeast strains, can be fermented warmer than we’ve been taught without the feared consequences. I don’t expect anyone else to adopt this blasphemous perspective, of course 🍻

[@adamgodofwar666]

I did a lager with equal parts weyerman pilsner, Vienna, and munich malts and fermented with 34/70. In my mind it was time to see what would happen doing this hot. I pitched at 69 degrees and full swing fermentation my tilt read as high as 77 degrees Fahrenheit. It turned out to be one of the cleanest beers I've brewed yet using that strain! The other times I used it was at 50 degrees and I couldn't taste a bit of Ester In wither hot or cold. I wouldn't worry if you don't have a temperature control if you want to use 34/70

[@NoMusiciansInMusicAnymore]

I think not using a special new yeast specifically geared for pressure fermentation was more of a backfiring ad than science in this one, I think a better test would be running with standard yeasts

[@mr.d578]

I have fermented wort at 19c, using W-34/70, S-23, and L17 Harvest - all under pressure. To my palate, I've noticed any difference to the times I've fermented with the above yeast strains cool or warm, under atmospheric pressure. My hypothesis is that many home brewers need an excuse to believe you can break convention and not end up with an inferior product - in this case pressure fermentation - see Kveik also. Saying that, I still ferment under pressure, but only to keep the krausen in check as I ferment in corny kegs.

[@TheBruSho]

So basically everything we are ever told is a lie! Thanks for "ruining" the hobby Martin 😅

[@Marshall_Brulosophy]

Hey now, don't go putting on Martin what is rightfully mine! I RUINED HOMEBREWING! Trust me, some guys who brew lagers a very specific way and also a guy named Bob told me so.

[@jamesspinks716]

The only way to tell is by the label on the can?

[@AlexBradford23]

I wonder if the mesh hop basket holds back the IBU's. Maybe an experiment with one batch with the hop basket and one batch with hops in the kettle

[@rogermurtaugh6248]

That’s exactly what I was thinking. I always hear people say do not use a hop spider because it confines the hop characteristics too much. Your test proposal sounds like a fun thing to see!

[@AlexBradford23]

@rogermurtaugh6248 I know the only batch that I did using the clawhammer whirlpool arm and tossing hops straight in was my best neipa to date

[@lukasthielmann]

12psi is about enough to approximate hydrostatic pressure in big macro tanks. If you want to mimick what some of those guys do with added pressure you gotta go higher (20-30psi). DrHans’s channel has great info about it. Basically use a carbonation Calc to match temp and pressure. Works great for me! (Pilsner in 10days grain to glass)

[@DENIEL1908]

Which video was that? I am just about to try pressure fermenting with a raw neipa, I wanna study all the videos in the topic. Thanks! 🍻

[@GeeScottJay]

They were both fermented at 20C? So since they tasted the same and were maybe different analytically, it's not like, "using this yeast under pressure and warm temp gets you lager flavour" it's actually that "using this yeast at warm temp gets you lager flavour" and the pressure isn't needed, right?

[@benjacobs3820]

This was what I was thinking. This was a good way to show fermenting under pressure doesn't fundamentally change the beer, but I understood fermenting at pressure allows us to use normal lager yeasts at a higher temperature with similar results. It would be good to have another proper test made with this in mind!

[@donosborn]

What a detailed experiment and how great to have some scientific data results. Still, when thinking about pressure fermenting I'm always wondering how much different it is than fermenting with the same yeast at cold temps and no pressure. That is, if I don't have cold temps and I want to make a lager, will pressurized fermenting at warmer temps provide a fairly close result. It is interesting, though, that in this case the pressure didn't do much. We have been hearing in recent years that lager yeasts can ferment much warmer than traditionally thought w/o negative results and this experiment does indicate that. Cheers.

[@Styv93]

I always ferment under pressure at 24°C using normal lager yeasts. I never had a difference in flavour or aroma compared to cold fermented lagers

[@Hellbrews]

So at the End the main "advantage" on pressure fermentations are Higher Fermtn Temp with lager strains, and saving some CO2 for carbonation? Cheers Mate ! 👏🍻

[@ittos90]

I wonder if the blend of yeast used in this experiment is what caused the similarities. After all, that was the intention of the blend - to be useful in many situations. I wonder if you'd have different results with a standard lager yeast at 68 pressurized vs un-pressurized

[@robertjoyce5629]

I think you should do the same ex-beer-iment again, but this time ferment both samples at 85 degrees Fahrenheit. I bet you'll get some noticeable differences then!

[@Marshall_Brulosophy]

We'll add it to the list!

[@pv4669]

The IBU difference was dramatic from Brewfather to the tested samples. Something tells me we've all been doing this wrong. Further Brülosophy investigation?

[@johnfinderupnielsen4174]

Which IBU formula did you use? It's interesting 15:55 that when I loaded your recipe into my Brewfather app it calculated 50 IBU with the Tinseth formula and 34 with the Garetz formula. Garezt seems to calculate lower in general. Wonder what the SMPH formula would calculate. I will recommend the IBU calculation article in BYO July-Aug 2022 edition.

[@AM2PMReviews]

I just got a few styles of mini kegs for cider pressure fermenting. What is the deal with lager vs ale fermentation? Is it just a temperature difference? Maybe pressure fermentation is just a little better since it's less exposure to oxygen, faster, hotter, less to clean, less Co2 needed?

[@CozzyB]

Wouldn’t the most obviously IBU being off factor be the hop spider? I’ve always suspected my utilisation is lower when using mine as much lower contact surface

[@derDKP]

Seems like a good thing to test

[@AdamNotThatAdam]

Maybe an exBEERiment as scientific as this to test hop utilization with and without a hop basket.

[@ants9230]

@@AdamNotThatAdam Pretty sure it was already done within the last couple of months. From memory, there was no discernable difference in the beers. Similar result to this one if I recall.

[@AdamNotThatAdam]

​@ants9230 was that sent to a lab? If so, do you have the link.

[@andkar83]

Very interesting, may I recommend that next time you crank up the temperature to 24-25 degrees Celsius. That should increase the difference in Esters and taste.

[@mikeseaman2809]

Interesting to see that the 0% beer actually came out better lab wise. Could that mean it would last longer in the bottle or keg? As for the IBU’s, I’ve always wondered if I’m getting quality hops as a home brewer. 🤷‍♂️

[@jonathanbaker6835]

Can we dig into IBU calculation?

[@JoeGraves24]

So my big fancy pressure fermenter was a waste of money?

[@diogolovato3074]

Probably not as they tested only one yeast strain

[@romsqabr]

This is gold, thanks a lot for sharing! Great video

[@omnitouchbb2408]

How do you think this would affect a NEIPA? I am thinking about waiting 4-5 days bring up to 10psi dry hopping day 6-7 staying under pressure till kegging/ canning

[@martinm3474]

One can of Premier Malt extract, one 4 lbs. bag of sugar, and one packet Red Star yeast in a seven gallon bucket. This worked for me over many years. It wasn't rocket science.

[@ew8253]

Why pressure? Fermentis has recommended their 34/70 yeast strain at higher temperatures (up to 20°C, 68°F) for years to make clean lagers quickly. You don't get more esters at that temperature. The conditions that made diacetyl were at low pitching rates and low temperature. They gave a great presentation at an AHA meeting a few years ago showing a lot of gas chromatograph and professional sensory panel data that shows ester thresholds well below perception levels. Marshall has pitched (see what I did there?) fermenting lagers in the 60's for a quite a while. I joined his blasphemous cult long ago. That being said, I typically ferment lagers in the mid 50°'s because I'm in no hurry. I'll continue to use 34/70 or a Czech strain. I'm very unlikely to invest in more equipment just to pressure ferment. Sure, commercial breweries have big tanks that ferment at pressure, but I'm a home brewer. Home brewing under pressure looks like a solution looking for a problem.

[@Homebrew58]

I seem to recall that in the past when you sent your homebrew out for testing you also got an extremely lower than expected IBU result. Could it be that all homebrewers should be skeptical about our software estimates and start increasing the amount of hops used?

[@cidmontenegro8225]

I wonder how White Labs data compares to the results of Martin's beer. They probably did this many times with many styles of beer, or more specifically, many yeasts.

[@pl_audio]

I accidentaly pitched a lager at 35c with 34/70. Set the fridge at 16c and let it rise to 22-23c after five days. I served it at a beer festival here in Sweden and one of the few tasters that actually said something about it said "Good job, it's crisp!"...

[@danmartvk]

This is cool to see all the lab work! great video I Pressure ferment all the time. Lager and Ale. Generally in the 25-27PSI range though. This is when I see the biggest benefit. First, because the beer is fully carbonated naturally. Second is the reduced off-flavors, higher PSI really does knock these down, other than diacetyl, as the labs showed. For Diacetyl ALDC is excellent, but the yeast needs to be extra healthy with O2 and extra nurturance to compensate for the stressful PSI. It is funny to see how off the IBU is, it seems all calculators are inaccurate at best when it comes to IBU. Without lab testing, it is a trial-and-iterate deal.

[@wd6358]

I agree with you as I've seen the same results at higher psi. Beautifully crisp, clean and more maltier lagers

[@Marshall_Brulosophy]

Regarding the IBU thing - we've had multiple beers tested over the years and this has been a very consistent finding, namely that lab measurements come back way lower than calculator predictions. My initial thought was, "Shit, I need to use more hops to ensure I hit the proper IBU!" However, the more I thought about it, the more I realized the error in this line of reasoning, mostly because we've generally been happy with the bitterness of the beers we've had tested. To me, this suggests that our predictive IBU calculators are just wholly different than the numbers returned by spectrophotometric assays or HPLC. I really don't know, but considering this particular xBmt, Martin would have had to use nearly double the amount of hops to achieve the "proper" IBU as measured in the lab, yet he felt both beers were already bitter enough and tasted great.

[@noregrats]

My first time using white labs yeast I was sent 2 packets that were stunted and runined 1 of the batches of beer I made. Contacted support and was told they would send me some yeast as a apology until they found out I was from Canada and told me a I had to pay import duty and the border for more than the yeast cost. They got some cool stuff when it works apparently but I'm sticking to dry after that disaster and their customer service.

[@tomwidauer8376]

It would be interesting to see the result with an ale instead of a lager. Esters play a much bigger part in ales and I'd like to see the difference. Although ales are usually pressure fermented at less than 5psi from what I gather.

[@ElementaryBrewingCo]

Great video!!! Just brewed a cold ipa with Mythical Hammer. I really enjoyed it! Great yeast, cheers 🍻

[@Xlr8ive]

I. pressure ferment regularly, it's just faster and easier, never tried clearing with gelatin, but I hear you can get a lager like result in less than a week! I still like to lager at cold temperature on co2 to increase my perception of crispness and let the beer clear, then dispense through a floating dip-tube. thanks for the rigorous testing it really convincing me to try fermenting in a whole variety of conditions, no wrong way!

[@williambellavance8784]

That was a great exBEERiment. Very interesting results, I have pressure fermented a few times in the past really not a lot as I never really noticed a difference. Great to see not a big difference between the two beers. Love the show and keep up the great work.

[@tomwidauer8376]

The fact that pressure fermenting shaves off a week in fermentation time and the beer is almost fully carbonated when it goes into the keg is a good enough reason to ferment my lagers under pressure 😀 Never done an ale though.

[@rcbran]

I'd like to know how and how fast you cooled these from boil to fermenter because there's a belief circulating that faster cooling may have an effect on IBUs. Thanks!

[@cg-404]

So for a professional homebrewer, there is no difference. Could this be replicated with extract kits and see if the weekend warrior gets different results on the more amateur scale of pressure fermentation

[@AM2PMReviews]

I want to know if anyone has hopped their beer in the glass with maybe a teabag. I have never heard of it but I love the flavor and aromas right out of the package for the fancy tropical hops. It might create a lot of nucleation points though or maybe garish the beer or cider with the hop like a cocktail would be amazing. I will try it.

[@Gutenmorgenside]

Great video, but who drinks all the beer you make ?

[@gamecollector7930]

Anton Paar SUUUUCKS, trust your hydrometer

[@xamolxis]

The music makes it hard to fallow what you say....

[@ScullyBrewing]

Very interesting regarding the IBU differences. It would be great to talk to developers about some possible improvements to IBU calculators for brewing software. I always thought that beers with lower IBU would be more accurate to estimate than say a triple IPA with 100+ IBU, but that wasnt the case here. Sidenote, are there any affordable IBU calculating machines? 😄

[@derDKP]

The biology lab at my local Community college has everything needed. Get a student to do a project?

[@KnobbyWobby]

Isn't 4/7 in the white labs test a statistically significant result?

[@TheAndysim66]

Many members of our Homebrew club have always thought the brewing software IBU calcs were too high, but I didn’t think they were that far off.

[@Sibula]

They can certainly be too high, but in some cases way too low. If you've ever tried to make a low IBU pale ale with generous late hop additions, you might notice you "10 IBU" beer tastes more like 20 IBU. The SMPH method of calculating IBU matches lab tests pretty well, but is much more complicated.

[@dustinlight4716]

I love seeing this level of detail and the inclusion of the quantitative analysis! I recently did a split batch myself to try this experiment with similar results on the quantitative side. Most of my friends couldn't tell the difference.

[@chrisleon7312]

So, Devon talked a load of bollocks...

[@GlennHill-jf4zh]

so up your Temps and see how high you can go

[@normodegard183]

More lab testing!

[@simontja]

please just show all data, not one data at a time.

[@TWillBeer]

The IBU discrepancy is interesting. I’ve been able to have a couple beers tested for IBUs and they also came out way under the brewers friend calculator estimates. 80 IBUs estimated/ 56 actual, and 35/7 as examples. Thats exactly the kind of rabbit hole that makes this hobby so appealing to me.

[@neilherke6285]

Did you use a hop spider? I don't think I get the same utilisation when I use mine vs dumping hops direct in the kettle

[@TWillBeer]

⁠@@neilherke6285free in the kettle. I stopped using spiders or bags years ago because of muted aroma and low bitterness. Maybe that wasn’t the only factor

[@gustag]

10:22 HEHEHEHEHEHEHHEHEHEHEHHEHEEHHEHE

[@rici_22]

Yeah, ditch the hop spider. Or better yet, do an xBmt on it and get a lab to measure IBUs. Then maybe Brewfather could add a "Using Hop Spider" tick box to their app that would make the appropriate IBU adjustments... My 2¢

[@flyingwombattv]

This is an absolutely brilliant episode mate! Love your channel but was truely spectacular to see such scientific rigour applied to testing a hypothesis at the home brew scale! I am curious how much of a qualitative & quantitative difference may be expected from a yeast that is supposed to be estery, say a Belgium yeast for example. Sure you wouldn’t really ever pressure ferment with an estery yeast but would be very interesting to see how much pressure ferm COULD suppress an estery yeast from getting estery

[@norbertmerkl572]

I'd love to see a same themed video but with new england IPA and dry hopping involved. I'd be curious about diacetyl levels on that one.

[@MrHayden123982]

My bet would be your hop basket for decreased utilization. You can adjust utilization in the app if you haven’t yet. Also curious if you have all of your volumes in brewfather for things like trub waste, pre boil, etc. some people never adjust to mimic their exact results on brew day and if your volume in the app was sig diff from real life, then it could over approx IBU

[@Wally-r1f]

Great video 👍

[@gregflynn1107]

I thought the reason for pressure fermentation is that you could ferment at higher temperatures, not that there would be a noticeable difference at slightly higher than recommended temps. Seems like a better experiment would be to ferment sub 16C and pressure ferment much higher, say 22-24C. I’m in South Florida so both getting my wort to fermentation temp is hard to do timely and requires refrigeration to hold fermentation below 25C and in summer it is hard to get it below 30C.

[@cabe_bedlam]

Feel this one was a better showcase for the Mythical Hammer than pressure fermentation. It would be interesting to see this test again with a “traditional” yeast to see how much the super strain helped.

[@jacksonakson8224]

My take, and current dilemma.... The 2022 European hop crop is substandard at best.

[@hansch-n1h]

Let your son try :)

[@pdescham496]

Great stuff would be awesome to see a more exagerated situation.. Lager fermenting at 27c with 0 and 12 PSI :)

[@kis1815]

Doing this on a commercial scale, the pressured one would probably end up having way more fusel alcohol and even acetaldehyde than the no pressure one, becasue the yeast would be very stressed and won't metabolize properly . Hence so many European lager breweries would use open fermentation instead. I have no clue who come up with this couple years ago, but a few blind tests don't prove the harm this method on lager.

[@wd6358]

My 2 best lagers have come from 'accidentally' having the temps in the low to mid 70's F and pressure north of 25 psi. I may actually target those ranges on all my lagers in the future due to how good the resulting product is. (S-23 and 34/70 were the yeasts)

[@oldschoolman1444]

I brew ales and use a pressure fermenter at 7 lbs at 22c. The things i like is the control of the crousen, closed transfers and carbonation. Also good for purging sanitizer from kegs.

[@davec4955]

My main reason for pressure fermentation is to carbonate during fermentation, so I'm delighted with the results of your test.🍻🍻

[@grahamhawes7089]

I pressure fermented lagers for quite a while before buying my fermentation chest freezer. I used a variety of yeast strains - my favorite for pressure fermentation was Mexican Lager, though I don’t love it for traditional fermentation. While the pressure-ferm beers were good, and dropped very clear, ALL of them had a very slight sulfurous note compared to cool-fermented lagers, regardless of yeast strains. These days I ferment at traditional temperatures but on an aggressive schedule, and spund the last few gravity points for carbonation.

[@clevelandmortician3887]

If I drank a couple of one then switched to the other I feel like I would know immediately. Taking that test would be a different story though

[@paulandersonanderson1444]

I think pressure become more important at higher temperatures. I’ve used US05 at in the middle of the Australian summer and the temperature of the beer hit 29 degrees Celsius. It was under pressure and had no detectable off flavours. I also do lagers in summer under pressure with no cooling and they also turn out great.

[@horn8mech]

My understanding is that fermenting under pressure at room temp gives similar results as fermenting cold without pressure. This experiment fermented at the same temperature pressurized and unpressurized.

[@Fairlylocalhomebrewery]

1 thing i think you missed is the clarity? Was there any difference in appearance? Did pressure help clarify it any more than zero pressure?

[@IMakeBeer]

Awesome awesome job again Martin. I love the “scientific” aspect you and Brulosophy are doing.

[@CrazyAboutVinylRecords]

10:08 "And if we run out of beer to test we can double as a urinalysis lab during the slow times." Lol.

[@1TheLord1]

Not going to lie... that's so awsome! What a nice support for white labs with the lab results.

[@bradleybarth9939]

Nice video. Looks like you missed adding your video link at the end.

[@gamefreeks]

Lots of good data points here! Thanks for sharing, great video!!!

[@Seb_Brannigan]

Greetings from Dortmund :-)

[@homebrewmania]

This was a great video! I'd love to see more videos with the quantitative results.

[@wyatth4497]

I loved the in depth details on this. THANKS!

[@RichardDePas]

Fantastic information. I had heard that pressure fermentation would increase hop flavors. It sounds like that is not true. Typically I ferment under pressure with a Fermzilla.

[@timwood8733]

fantastic to actually see some actual lab results -well done

[@Abeyptfc]

Great video once again mate👍

[@suwirwong]

Try test budweizer

[@AndreiAdamtsuk]

Hello Martin!

[@bjsgordo]

Great vídeo

[@paskrell]

It’s the strain!! Do again with 34/70. 😅😅😅 I’ve done it (cold no pressure vs warm pressure) and it was easy to see difference.

[@Marshall_Brulosophy]

We've done that! Both beers fermented with W-34/70 at 68F/20C, one at 12 psi the other at ambient temp, and only 8 out of 20 blind tasters identified the unique sample. I'd drop a link, but last time I did that, I was banned from commenting for a few days... despite this being my channel. If you're interested, you can find the article by searching "Impact Of Pressurized Warm Fermentation On A Festbier." We've also done the same test with other lager yeasts and consistently get the same result, which is to say tasters cannot reliably distinguish the beers based on aroma, flavor, or mouthfeel.

[@Marshall_Brulosophy]

I just realized you proposed a dual variable experiment comparing a lager fermented cool with no pressure (standard) to one fermented warm under pressure. My bad. My understanding is that the argument for pressurized fermentation is that one can get away with fermenting warmer without the risk of producing stylistically inappropriate fermentation byproducts (esters, fusels, etc). It sounds like you're claiming that fermenting under pressure even when keeping the temp cool has benefits as well?

[@Murzington]

I was under the impression that the point in pressure fermentation was to do so at higher temp. This experiment should have been a comparison of a split batch where one half is done normal (standard lager temps and no pressure) and the other half done under pressure at ale temps (12psi 72ish F). That's where all the comparisons and anecdotal evidence is.

[@jonasragnarsson6143]

How about to ferment whith pressure and low temp? Will ett come out super clean with no esters? Or do the yeast turn in and out and say godbye?

[@paskrell]

@@jonasragnarsson6143 personally I’ve always done 20C at 1bar and a gold and silver medal later snd a 5th with proper temp control I’ll continue 20C 1bar 😉

[@jgar538]

I'm sorry for giving you a thumbs down, but I was expecting a comparison of normal lager fermentation (50-53 F) and pressure fermentation (at 65-68 F) using a standard lager yeast. Cheerz.

[@ericrolerkite951]

Not sure if this has been commented, but I bet your hop strainer prevented a lot of utilization of hops. I recently started brewing in stainless basket and I’ve been getting a lot of astringency in my final product. It be cool to see a Brew experiment on astringency. Such as over sparging heating up the entire grain basket, so on so on.

[@dibbsonline]

18 minutes of your life you'll never get back.

[@friedfishfury]

tastes like spit or some reason