Author: Marshall Schott
Back in June 2014, I performed The Great Trub exBEERiment, which suggested fermenting beer with higher amounts of kettle trub led to a clearer beer with a crisper taste. Data collection for this xBmt was somewhat clunky, as I’d yet to fully hone my method. While I did perform a triangle test, it wasn’t the focus, which led some to question the validity of the results, understandably so.
Since that article was published, I’ve heard from many (many) people who either had been fermenting with tons of kettle trub or who started doing so after reading the article, all who claimed to have a similar results. Prior to the xBmt, I was one of those brewers who would allow the trub to settle out before racking, though I’ve since stopped worrying near as much and I don’t believe it’s had a negative impact on the beer I make. Regardless, I’d been wanting to get back to this one using the slightly more controlled data collection method I’ve since adopted. And besides, a single point of data does not a principle make.
| PURPOSE |
To compare the impact different amounts of kettle trub in the fermentor have on 2 beers made from the same wort and fermented with the same yeast.
| METHOD |
I had recently decided I wanted to submit a Vienna Lager in the NHC and only had about a month until the beers were due, hence my choice of style. I was also interested to see how kettle trub might have a different impact using my yeast of choice for this beer, WLP 810 San Francisco Lager Yeast.
NHC Vienna Lager
| Batch Size | Boil Time | IBU | SRM | OG | Est. FG | ABV |
|---|---|---|---|---|---|---|
| 11 gal | 75 min | 22.1 | 11.4 | 1.053 SG | 1.013 SG | 5.2% |
Fermentables
| Name | Amount | % |
|---|---|---|
| Gambrinus Vienna Malt | 9 lbs | 48 |
| Franco-Belges Belgian Pils Malt | 6 lbs | 32 |
| Gambrinus Munich 10 Malt | 3 lbs | 16 |
| Gambrinus Honey Malt | 8 oz | 2.7 |
| Briess Midnight Wheat | 4 oz | 1.3 |
Hops
| Name | Amt/IBU | Time | Use | Form | Alpha % |
|---|---|---|---|---|---|
| Magnum | ~20.3 IBU | 60 min | Boil | Pellet | 12.2 |
| Spalt | 40 g/1.9 IBU | 10 min | Boil | Pellet | 3.1 |
Yeast
| Name | Lab | Attenuation | Ferm Temp |
|---|---|---|---|
| WLP810 San Francisco Lager Yeast | White Labs | 65-70% | 58°F |
A few days prior to brewing, I made a large enough starter to propagate the predicted amount of yeast for two 5 gallon batches of 1.053 OG wort. This would later be evenly split and decanted before being pitched.
The brew day started out as usual, early in the morning, and I nailed my mash temps. After an hourlong mash, the wort was collected, the boil commenced, hops were added, then the wort was chilled to 58˚F, my target fermentation temperature. I should add that 8 grams of Irish moss was added at 5 minutes to flameout.
In order to maximize the amount of trub transferred to the high-trub fermentor, I tilted the kettle forward and used a spoon to gently coax as much out as possible. Once that carboy was full, I tilted the kettle backward and let the trub settle for 15 minutes before opening the valve and filling the no-trub fermentor.
I can’t seem to find the picture, but suffice it to say the difference between the carboys was stark. Both were placed in the fermentation chamber and pitched with equal amounts of WLP810. This is where the observable differences began. The high-trub beer showed active signs of fermentation hours before the no-trub and appeared to ferment with more vigor. The no-trub beer eventually appeared to be catching up and by a week post-pitch, after the temp had been ramped to 68˚F, the krausen had pretty much fallen on both beers and airlock activity was at a standstill.
I took an intial hydrometer reading a few days later and immediately noticed some differences.
While neither beer had attenuated to expected FG, I was pretty surprised to discover the no-trub beer was barely below 1.030 SG. Also, the high-trub beer was already looking a bit clearer by comparison.
In order to encourage a bit more attenuation, I bumped the temp on my Black Box regulator to 72˚F and let both beers sit a few more days. The high-trub batch maintained its appearance for the most part, while the no-trub batch began developing interesting looking bubbles on the surface of the beer.
After a few days at this warmer temp, I took a second hydrometer reading.
It’s interesting to note the expected FG for this beer was 1.013, which the high-trub beer had surpassed and the no-trub beer was still above. To be sure, I let the beers sit another few days before taking third and fourth hydrometer samples 2 days apart, the readings were consistent at this point.
After being cold crashed and fined with gelatin, I kegged the beers then placed them in my keezer to carbonate.
The difference between each batch in terms of overall trub amount was pretty drastic.
The beers were left to condition/lager and carbonate for about week before being presented to participants for evaluation, at which point they were about as clear as any commercially available example (condensation be damned).
| RESULTS |
Besides generally tightening things up in terms of data collection compared to the first kettle trub xBmt, another important-to-note difference is that the samples for this one were served to each taster in opaque cups, meaning they would be forced to rely on characteristics other than appearance to make their determination. In all, 18 people participated in this xBmt, requiring a minimum of 10 (p<0.05) to choose the different beer to reach statistical significance. Each person was blindly served 3 samples, 2 of which were the no-trub beer. A total of 8 tasters correctly identified the high-trub beer as being different from the others, while the other 10 participants chose either of the similar samples. Yet again, these results suggest there is no statistically significant perceptible difference between beers fermented with very high and very low amounts of kettle trub.
But what about the people who did taste a difference?
Given the fact we were only 2 tasters short of reaching significance, I thought it might be interesting to share the perspectives of those who were correct when asked to compare only the 2 different beers. Please, when reading this next part, do so with the understanding that these are meaningless findings from a purely statistical perspective. Sure, there’s a chance the correct tasters just have better palates, but the dickhead in me is compelled to think they’re likely just better guessers.
Of the 8 participants who accurately selected the high-trub beers as being the different sample…
…all but 1 perceived the aroma to be somewhat similar, that single straggler believing they were not at all similar; 5 preferred the aroma of the no-trub sample and 3 preferred the aroma of the high-trub sample.
…everyone felt the flavor was somewhat similar with, again, 5 preferring no-trub and 3 preferring high-trub.
…5 tasters perceived the mouthfeel as being somewhat similar, 2 as exactly the same, and 1 person though they were not at all similar; of those who thought there was a difference, 2 preferred the mouthfeel of the no-trub beer while 4 preferred the high-trub beer.
My Impressions: As usual, I began drinking these beers a few days prior to the start of data collection and from the very first comparative sip, I knew which one I’d be entering into the National Homebrew Competition. Whether due to bias (probably) or not, I much preferred the beer fermented with a ton of kettle trub, not just because it had what I perceived to be as a crisper, cleaner flavor, but for some reason the no-trub beer had what I can only describe as a subtle plastic aroma and flavor, something I’ve only ever experienced one other time when I significantly under-pitched harvested yeast into a 1.055 wort. Was this the effects of yeast stress? Is there something about kettle trub that ameliorates the these types of off-flavors? Am I just making this up?
| DISCUSSION |
The lack of statistical significance in this xBmt supports previous findings, as well as the anecdotal reports of myriad homebrewers, that higher amounts of kettle trub making it to the fermentor do not necessarily impact beer in a detrimental way, as many were taught to believe. Since the appearance of each beer was not evaluated, in addition to the fact both batches were fined with gelatin, a comment on the clarifying function of kettle trub cannot be made. Moreover, the easily observable differences in fermentation vigor, overall attenuation, and time to reach FG between each batch suggests something about kettle trub contributes positively to fermentation activity in general. While I’m uncomfortable and far too stupid to make any claims of certainly as to why this is the case, I’ve heard speculation that it has something to do with increased lipids… I won’t pretend to know more than I do. In the end, these results have only served to solidify my belief that worrying about racking only the clearest wort to the fermentor is unfounded and a waste of energy.
Since revealing the results of the first trub xBmt, many folks have proposed the idea that perhaps increased kettle trub during fermentation has some negative impact on shelf life. I have to admit, shelf-life isn’t something I’ve ever been terribly concerned with when it comes to homebrewing, as most of my batches stick around for maybe a month. Still, for those who sit on their beer longer, this is certainly a major limitation to my research. For what it’s worth, I’m currently sipping a pint of the high-trub Vienna lager, brewed nearly 6 weeks ago, and it is delicious! I still experience that whisper of plastic in the no-trub beer, though really, it’s quite tasty as well. I ended up entering the high-trub version in NHC, here’s to hoping it does as well as I hope!
Are you a filterer or a toss-it-all-in type? Regardless, please don’t hesitate to share your experience in the comments section below. Cheers!
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57 thoughts on “exBEERiment | Kettle Trub: High Vs. Low In A Vienna Lager”
Have you made any observations in regard to heavily hopped beers? For instance, I have been adding more late addition/whirlpool/hopstand hops to see about eliminating dry hopping. A recent citra IPA I brewed with a lot of hops in a hopstand was so good I skipped the dry hop. I have been going to great (greater than necessary????) lengths to leave behind the majority of hop material in the kettle. These are beers with 1-2 ounces of hops through the boil, and then 8-10 ounces of hops 5 minutes and under. Long hop stand of 30-45 minutes or so, another 30-45 minutes chilling and just settling out after chilling before going to the fermenter. I routinely leave 1+ gallons behind in the kettle with 80-90% of the hop material. I am brewing about 6.5 gallon finished to get close to 5 gallons into the keg ultimately. Wondering if dumping 8 ounces of kettle hop material into the fermenter would be as undetectable as regular “trub” with small amts of hops. Have you tried that, even informally? Another great write up. Thanks.
I’m also curious about fermenting on top of a large mass of hop pellets. Does the resulting beer have unpleasant hop character from the hops? I realize some of the hops will get buried under the yeast and particulate, but some of it will be whirling around with the convection currents I would think. I need to do some tests for myself soon!
I once tested (not side by side) something like this– I added a 2 oz dry hop charge at the same time as pitching the yeast, the beer actually came out just fine… anecdotally.
I’ve not done a trub xBmt on a highly hopped beer, though I think for logistical reasons regarding packaging volume, I’d probably not rack all of the hop matter to the carboy. Also, I tend to think the positive impact comes more from the break material than the vegetal hop material.
I’ve noticed since getting a CFC that I am getting really good fermentations. I think one of the main benefits of junk in the fermenter is that there are areas for CO2 to nucleate. This might take some stress off of the yeast and also get them stirred up into the carboy more. When I used to ferment on perfectly clear wort, I used to shake the carboy once per day to drive off CO2 and get the yeast into suspension again. Though, I’m certain you are correct that the trub is giving nutrients to the yeast that really get it going well and give a good fermentation. Maybe as a last test you could do as others have asked and then TRY to just age the beers for maybe 3-4 months, then compare them. Thanks for all of the work you’ve done!
I accidently did such an experiment, when I brewed your Lil Slack Recipe a few weeks ago and had both a big boilover (so not a ton left in the kettle — all the trub went in) and many ounces of dry hops, per the recipe. It came out pretty much amazing, but given that I ferment in 6.5 gallon Better Bottles (so not a ton of space for extra wort in the fermenter), the amount I had to leave behind when it came to kegging time meant I had a lot of empty space in the keg — so I definitely had logistical issues regarding packing volume 🙂 Anecdote: despite the fact that I used neither whirlfloc nor gelatin (though I did cold crash for 5 days) it was one of the clearest beers I’ve ever made.
As far as I understand (that is, not very far), interaction with the hops is minimal bellow a certain temperature — 80°C for isomerisation of the resin, and lower (?) for essential oils. From what I’ve experienced, if the beer is crash cooled and/or if gelatin is used, most hop particles (that do taste harshly bitter and can float around) are discarded. So from purely anecdotal evidences, I’d go for leaving the trub. I’m currently sitting on a 7-ounces Nelson Sauvin APA in which the trub was entirely left, hopping for the best.
PS: Tiny, rare typo: “appeared be catching up”.
Great article, you have almost convinced me to sell my three vessel setup and go back to a cooler for a mash tun.
I leave my wort to settle a little bit after the boil, just because i loose , what i think, tremendous amounts of beer due to trub (from 5gal in fermenter i get less than 4gal in bottles), either i let trub settle after the boil or just dump it all in!
Your blog is a great source of practical information, cheers from Latvia!
And good luck in NHC with your Vienna lager! 😉
Prozīt! My wife is Lavian, maiden surname Berzinš 🙂
I would just like to thank you very much for all the knowledge you have imparted on all of us with your experiments. Unlike all the other so called “experts” out there, you at least scientifically prove your theorems, instead of just being believed because of your “expertise.” Knowing what you have done lets me relax A LOT more on brew day, as I don’t have to separate my trub, mash for a whole hour, worry about the irish moss additions, and the worst boogey monster of all: hot-side aeration. You, sir, are a beer god amongst men.
Awesome article, its comforting to know that all the trub I’ve been dumping into the fermenter over the years probably hasn’t been hurting my beer flavor. I’ll keep lifting the kettle and pouring it all in like a champ!
This is cool. Interesting that both beer attenuated to 78% and 82% respectively. Well past what I would have expected from that yeast. You didn’t detail your mash schedule… wonder if you mashed low?
I also noticed you didn’t really give a lot of tasting notes, other than the slightly phenolic hint in the no-trub version. Was it more malty? Was there any difference in hop bitterness?
Good job as always!
Single infusion, 148F, 60 minutes.
Was thinking that the trub beer may be fermenting on a much larger volume of yeast. Perhaps when you are racking off the trub you are leaving a lot of yeast behind?
Racking off the trub? I pitched similar volumes of yeast into both carbons and let them rip.
I just thought I’d Note that the 2 brews I sent you were bottle conditioned trubies! Basically emptied the kettle.
The Dunkel was 5 months old in the bottle (wlp029), and I thought it got better during that aging in the fridge, for not being a lager strain.
That Helles has been met by all as a clear, crisp and great tasting brew, again full trub and wlp029. It didn’t win our SMASH contest, but it was the only brew commented on by several members.
My Truby barleywine exceeded the wyeast1084 published alcohol tolerance, finishing in under 6 days, when I didn’t even expect to come close on my 1st big beer. Maybe the trub helped them. I was sure I’d have to bring in the second string to finish off that 1.114 down to 1.020
I have done it both ways and provided I cold crash the trub containing beers prior to racking, I observe no difference in flavor or appearance. The trub containing beers do begin active fermentation more quickly in my experience. My MO is to just leave the fermenting beers alone for 10-14 days, so I can’t comment as to how quickly they reach terminal gravity.
Appreciate your blogging on these Xbrmnts. Keep up the great work.
Have you considered that trub may contain essential proteins and other micronutrients necessary for budding and replication of yeast? It sounds like the yeast were slightly lacking some factor which slowed their replication rate, stressed them slightly, and produced the off flavor. From my understanding, trub contains mostly denser proteins (or more depending on using Irish moss).
I’ve certain considered it, I’m just nowhere near smart enough to really know if that’s the case.
I’ve seen at least one professional brewing article showing the increase in zinc ions that are available to the yeast when hot trub is in contact with the wort in the fermenter. Worts that were clearly-lautered and contained no hot trub contained the least zinc of any of the worts. You might minimize fermentation differences further if you dose the clear wort with zinc nutrient if you want another fun project to try. There could also be fatty acids necessary for yeast metabolism in the hot trub that boost yeast growth and activity. The paper I read also said that there was a larger yeast mass in the fermenters containing hot trub as well.
The article I read is J. Am. Soc. Brew. Chem. 64(1):16-28, 2006.
They also found that by stirring their mash to get a more “turbid” wort they were able to get excellent fermenations, flavors and stability.
I know the triangle focused on palate vs visual perception; however, were there any personally perceived visual differences? One that I am most curious about is head retention – clarity, IME, can be equalized with finings (I too use gelatin).
I meant to mention it, but there really is no noticeable difference in appearance– head retention, color, and clarity (gelatin?) we’re all WNL.
While I am 100% convinced that trub is a non-issue, in this experiment, something about the combination of (a) a very slow start, and (b) a plastic aftertaste in non-truby makes me worry that something extraneous was going on with that batch. Something in that carboy maybe. After all, it was Spinoza who said, “even the expert homebrewer can’t prevent every single potential mishap.”
Keep in mind, my incredibly biased palate is the only one who perceived the VERY subtle plastic-like character. I’d suggest folks trust the panel more than me.
I vaguely recall Spinoza saying exactly that 😉
I would love a xBmt on hop matter transferred to the fermenter. Specifically loose hop pellets in the boil vs. using a hop spider or bags while brewing an IPA. It would be interesting to test the hop utilization of being confined in the boil as well as any off flavors from loose hops making their way to the fermenter.
It’s on the list!
Isn’t that basically what this experiment is about? Or you’d like something specific to hop matter, rather than hop+proteins?
I’d like a comparison on a super hop-bomb beer, obviously an IPA or DIPA, adding most of the hops in whirlpool or late and see if the hops-in-fermenter is tannic/chlorophylic/bitter, etc.
Jason, the Barleywine I mentioned above had most of the 4.2oz of hops make it into the fermenter. I also have a recipe on the milder side of aroma/flavor for an IPA with several ounces of pellets. I just throw them into the boil, and thus the fermenter for 14 days. All is well so far with no untrained off flavors detected. I’m not a hop head or a BJCP yet, though.
I’m with Ben! Shout out to Brulosopher, Cuz my beer keeps getting cleaner, clearer, etc
Like a lot of homebrewers, I used to try in vain to keep trub out of fermentors. Hop spiders, paint strainer bags, bazooka screens, and dip tubes – oh my! I got rid of all that junk and I flow straight outta the bulkhead, transferring tons of trub. My beer has never tasted better, and never been clearer. Thanks for showing us the way!
My own experiences brewing confirm the result of this experiment.
Good on ya once again, man. I’m one of the myriad you mention and it’s great to see you verify what I’ve told people for years.
I did the same experiment and the yeast really had to work hard to ferment the No-trub beer. They both ended up at the same FG but the Trub was much faster.
The taste? No idea since I just had one keg available so they both went in that one. Stupid, I know, but it was the only thing to do then.
I actually saved a sample of each on bottle but unfortunately someone found them during a party and non of us remember which was best. 😉
Matt Duplicated it too…
http://tobrewabeer.com/trub-vs-no-trub-replicating-the-great-trub-exbeeriment/
Whoops! Sorry Just realized I re-posted the link of Drakes
So glad to know this. All my beers have fermented with a ton of trub, especially now that I employ a One Pot Brewing system (one vessel for mash, boil, ferment, bottle).
I’d love to hear more about your 1 vessel system.
http://www.onepotbrewing.wordpress.com for details. It’s a 7.5 gallon aluminum pot with spigot.
Perhaps the difference in attenuation could be contributed to more sites for the yeast to use, similar to the beechwood aging process where it shortens the maturation time because of the increased surface area for the yeast which have flocculated.
I never get lower FG than 1,015-1,020 with wlp810. How big are your starters?
Depends on age of yeast and OG, but usually 1-2L. I also mash around 148F.
Really interesting! I’ve got a little pet hypothesis I’m trying out that’s related to your experiment and someone pointed me to your blog… I’m trying to track down one of the tastes of “homebrew” that set it apart from other beer, specifically what goes wrong with some brews that end up with off-putting hop character. Currently I’m thinking that the wort infuses with the hop dirt to some extent, either before, during, or after fermentation and that it may be specifically the alcohol that adds the “tangy bitterness on the back end” described by many of your tasters in the first article (linked for reference) https://brulosophy.com/2014/06/02/the-great-trub-exbeeriment-results-are-in/
Perhaps it’s not about temperature, it’s about alcohol pulling specific flavors out of exhausted, old hops. I’m also thinking that hop dirt (at least at pellet hop levels) isn’t really what the ‘brewers of old’ had in mind when it came to trub, and our definition of what trub is has expanded to include lots of hops that it didn’t include in the past.
Try making a hop-infused vodka and you’ll see what I mean – it’s very bitter and not much else. Trub may be okay and may even be good, and trub with a little hops might not be bad, but my thesis is that trub with a lot of hop dirt in it may make your beer tangy and bitter, and those flavors are probably extracted by the alcohol, meaning that people who don’t strain and/or don’t rack to secondary and/or don’t use whole or leaf hops in the boil are more effected. Sometimes it may be a plus for your beer and even a part of the recipe, but other times it will mess things up.
I’m very interested in the ideas you shared here, feel free to email me directly if you want to chat further. Cheers!
That’s an interesting question. Did you guys figure out an experiment that can shed light on this?
Nice experiment! I’ve definitely noticed improved clarity and attenuation with trub in the fermenter.
I’m wondering how to deal with trub’s influence on apparent volumes and resulting efficiency calculations.
Here’s my problem: typically, “trub” is subtracted from kettle volume to arrive at fermenter volume, which gives you your brewhouse efficiency. With trub going to the fermenter, should I try to subtract the volume of trub from the total volume in the fermenter before calculating efficiency? Seems like I should.
If you are certain of the amount of trub you’re racking into your fermentor, that’s not a bad idea.
In my experience, the “tang” or “twang” is often either oxidation, poor fermentation, or too high of pH throughout the process.
Fix those and 90% of HB really is pretty good. Of course, that assumes a good recipe – but if you get criticism on recipe that’s good IMO. Recipe formulation is an easy fix and means all else is going well.
I also used Notty in that first trub xBmt, I always he some “tang” from that yeast.
I loathe that yeast. I’ve tasted decent beer made with it – but none of them came from my fermenters. Rather than try to master it I moved on.
I don’t think we’re talking about the same flavor, although those are certainly things that can happen.
These days I typically brew once a year, and I use the award-winning AHA big brew recipes. Sometimes they’ve been altered (hop bill, etc.). Friends of mine will brew the same recipe. Sometimes things will just taste off, and off in a hoppy kind of way. I don’t think it’s skunked or anything like that. I’m fairly certain of my water, PH, etc. I take gravity readings and usually hit my targets. Everything is clean and sanitized. If I use a wine thief on a calm carboy I shoot in some CO2 from my tank to prevent oxidation. I ferment at higher temperatures than recommended, but under 78F.
People are rarely blown away by these brews – they don’t taste bad, they just don’t taste like the medal winners they’re supposed to be. Often they have the flavor I’m talking about – a tangy hop thing on the front and a bitter back end, similar to the hop vodka. We’re talking about many batches, all the same recipe and ingredients, different brewers, same off-flavor.
At least in the near future I’ll be using whole or leaf hops in all my brews – I’ve fairly convinced myself that the hop dirt that makes it into the carboy can’t be an inert ingredient. I’m also thinking that the presence of alcohol is what is pulling flavor out of the hop dirt, although it probably has something left in it that is water-soluble after the boil, so racking to secondary after primary ferment is what I’m going to do to my current batch.
While I will certainly not rule something out without tasting myself – but I personally do not see a “hop dirt” issue. Millions of batches have been and are being brewed with both pellets and cone hops. This is more than likely a process issue. How are you certain of your pH? Especially compared to your friends who brew similar beers? Why are they not experiencing “hop-dirt-atosis” (sorry -my daughter is on a Doc McStuffins kick). Twang is almost always due to what I described above. High pH is a common issue for those not reducing their alkalinity (obviously in area with higher bicarb in their water) and it undoubtedly alters the beer – not always in a bad way – but the mouthfeel, hop utilization, malt presence, color etc ….all affected.
Brewing only a few times a year means you more than likely have not nailed your process yet – not a big deal as it is a hobby after all – but it means it’ll more difficult to troubleshoot any failings with such a long feedback loop and lack of practice with your own methods.
I never thought of dry-hopping a low concentration solution of ethanol to see what happens. Tha is genius! It would seem that the ethanol is probably the primary reason the flavors from the dry hops leach into the beer solution: though, the other organic compounds in the beer may help too. I’m going to do some small-scale experiments to try this!
I think that it is possible that forcing people to make a choice in the triangle test is basically watering down the significance, because the people that can’t tell are averaging out the ones that can. You should report the percent that got it right among the people who claim to be fairly confident in their choice.
Another way of looking at this is to ask what population of people you are trying to represent with this sample – all beer drinkers? all craft beer drinkers? all immediate friends of Brulosopher? This question should ideally determine who tastes the beers. The beers could very well be completely different from each other, but if you are not a very perceptive taster, you will never see that. You could ask the same number of professionally-trained, sensitive tasters from the Budweiser sensory perception lab and get 100% perfect results. That’s a reason why the triangle test is as much of a test of your tasters as it is a test of your beers. I think the exBeeriment with the same beer being perceived differently by tasters is a perfect example of that. I think the sample in this case is trying to be representative of average to pretty perceptive homebrewers and craft beer drinkers. The results don’t mean the beers are NOT different. It means that the odds are that if you sample from this population being tested there is a pretty good chance there won’t be consensus as to whether there is a difference or not.
On trubby’s faster (healthier?) activity, I wonder if this statement from wyeast lab had anything to do with it:
http://www.wyeastlab.com/oxygenation
“The unsaturated fatty acids found in wort trub can be utilized by yeast for membrane synthesis. If wort trub levels are low, yeast will need to synthesize more of these lipids and therefore will require more oxygen.”
Man, it Would be nice to see another Trub xBmt made with an IPA, Double IPA or NEIPA. I don’t know, something with a higher amount of hop addition and tons of dry-hopping in the end, don’t you think?