The Brew Matrix Experiment #2 - Mash Fines in the Boil x Kettle Trub in the Fermenter

[Bobby_M]

The tasting happened last night and 19 tasters provided ratings via Google forms so I can manipulate the data relatively easily rather than trying to read handwriting. I'm compiling the responses into more digestible data and will report back soon enough but I just wanted to tease that there were significant differences in the beers in both clarity and flavor.

I did pour a 5th cup "E" that was randomly selected from the four actual variable samples that I used to test for sensory reliability. If a taster rated the duplicate the same as its mate, they get their response slightly amplified. BJCP judges get a rating boost based on their rank as well. I'll show raw and weighted results.

 

[mrcastellino]

Looking forward to the report out!!

 

[corncob]

Edge of my damn seat

 

[Bassman2003]

Thanks Bobby. Looks like your setup is working out just as you intended.

 

[Bobby_M]

The video is up. I ended up calling this experiment #1 because I never really published any data on the first one and I kind of screwed it up anyway.

 

[corncob]

Fascinating. Thanks, Bobby.

 

[Bobby_M]

For those that TLDR; It SEEMS:

1. An excess of mash fines in the boil may degrade the flavor.
2. Some level of kettle trub (hot and cold break) transferred into the fermenter reduces lag time and helps the beer clear faster and more thoroughly.

The tricky part if figuring out where the threshold is. I forced more mash fines than most people could achieve by accident. I think another run at this is warranted just comparing a typical BIAB process to a vorlaufed dedicated mash tun runoff. The difference in mash fines in the boil would be way more subtle.
As I mentioned in the video, backing off on how fine you mill and reducing the amount of squeezing you do would like be two positive moves. Keep in mind that my pH was in an ideal range. I suspect, very uncontrovercially, that having a high pH in the realm of 5.8+ would make the silty boil sample worse than it was.

On the boil trub in the fermenter topic, I suspect that a very clean wort COULD perform like a trub-heavy transfer with the addition of nutrient and subsequent fining agents. I just don't know why you would do that.

I got to thinking about how one would nudge system design in a positive direction if you were to assume that the cleanest possible boil wort is "best". I'm not saying it is, yet, but let's assume there is no good enough threshold and there's a linear improvement the clearer the wort was in the boil.

For right now, I think it would look something like the Blichmann Brew Easy but with the lower kettle being bottom drained from the center (like the SPIKE Tank). The one detriment to running a Kettle RIMS boil kettle with a side pickup is that the beneficial swirling (for heat distribution) will also cause mash fines to collect in the center of the kettle and never get vorlaufed out. A center bottom drain would ensure that particles exited naturally and then get caught in the mash tun in the filter bed. A stacked kettle design retains the single pump requirement of a typical high end eBIAB setup.

 

[doug293cz]

It's interesting that the dirty boil, dirty ferment, scored slightly better than the clean boil, clean ferment. It also appears that a dirty ferment "fixes" a lot of whatever the detrimental effects of a dirty boil are. It also supports the idea that if you are not putting clean beer in the boil (like a lot of BIABers), you should definitely put some boil trub in the fermenter.

It's also interesting that your results align with the much maligned Brulosophy Exbeeriment showing a net benefit of trub in the fermenter when it comes to finished beer clarity, and subtle differences in taste with some tasters preferring the high trub beer, and some preferring the low.

Brew on

 

[VTMongoose]

Fantastic experiment Bobby, very well done start to finish, including the video, and graphics, of which I appreciate the considerable effort you put into inserting them into the video along with all of the images and other data. I would not have expected the results to be what they were. The most interesting outcome for me is that trub positively affected flocculation. I guess that the trub could contain positively charged molecules that attract the yeast, like how gelatin works. I also find it interesting that the clarity of the final beer correlates so well with its overall rating, when I expected the CBCF beer to be preferred by some tasters since it has yeast in suspension which carries with it hop and malt flavors.

One curiosity I have as the owner of something like 8+ RAPT pills at this point would be the fermentation kinetics. In my experience, both excessive lag times and slow ferments (at any stage) are both independently attributable to an unhealthy fermentation. I would have liked to drop a pill into each fermentor and see what the profiles looked like. Floating hydrometers are poor at absolute measurements of original and final gravity, but they are very good at identifying the different phases of yeast growth, their duration, and slope. I pay attention to these in my fermentations as it tells me whether my pitch rate and fermentation temperatures are appropriate.

Another curiosity I would have as someone that is sensitive to tannins (as mouthfeel) would be whether the bag squeeze samples were worse. Was it a poll option in your survey, or did anyone comment on it at the meet? Personally, I have never had tannin issues from bag squeezing, only from using rice hulls and 'non-dehusked' roasted malts.

I do not have anything but a borderline useless anecdote/speculation to add to this thread. I tend to brew with strains are known to produce more H2S than other strains, including Kolsch, Witbier, Hefeweizen, Augustiner Lager, etc. Some of these I have brewed more than once, and I have observed that a phase I went through obsessing over trub exclusion going into the fermentor anecdotally* (take with several grains of salt) led some of my most "farty" beers. Excluding trub should not, on paper, limit the amount of solubilized cysteine and methionine in the wort from mashing, so I am not sure what in the trub is having the beneficial effect on yeast nutrition and mitigation of this off-flavor, but I have switched to whirlpooling and resting a short time such that a certain 'non-zero' amount of trub makes it into my fermentor, and it seems to result in healthier fermentations coupled with the use of yeast nutrient.

 

[Bobby_M]

It's interesting that the dirty boil, dirty ferment, scored slightly better than the clean boil, clean ferment. It also appears that a dirty ferment "fixes" a lot of whatever the detrimental effects of a dirty boil are. It also supports the idea that if you are not putting clean beer in the boil (like a lot of BIABers), you should definitely put some boil trub in the fermenter.

It's also interesting that your results align with the much maligned Brulosophy Exbeeriment showing a net benefit of trub in the fermenter when it comes to finished beer clarity, and subtle differences in taste with some tasters preferring the high trub beer, and some preferring the low.

Brew on

Yeah, it's really strange stuff. I think that's one thing I said to the group directly following the tasting. Since it was done with Google forms, I saw the trend right away and said, it looks like putting trub into the fermenter is pretty important. The two "clean" ferment samples couldn't catch up in clarity even after 5 weeks in the cold.

 

[Bobby_M]

One curiosity I have as the owner of something like 8+ RAPT pills at this point would be the fermentation kinetics. In my experience, both excessive lag times and slow ferments (at any stage) are both independently attributable to an unhealthy fermentation. I would have liked to drop a pill into each fermentor and see what the profiles looked like. Floating hydrometers are poor at absolute measurements of original and final gravity, but they are very good at identifying the different phases of yeast growth, their duration, and slope. I pay attention to these in my fermentations as it tells me whether my pitch rate and fermentation temperatures are appropriate.

Admittedly, I took samples and measurements far fewer times than I wanted to. I'm lucky I got the 12 and 24 hour pictures.

Another curiosity I would have as someone that is sensitive to tannins (as mouthfeel) would be whether the bag squeeze samples were worse. Was it a poll option in your survey, or did anyone comment on it at the meet? Personally, I have never had tannin issues from bag squeezing, only from using rice hulls and 'non-dehusked' roasted malts.

No one noted tannins in the general comments on the form or in person following the tasting. This is likely due to the mash pH being 5.3ish across the board. In my humble opinion, I think A was clearly flawed. It was the only one out of the four that I wouldn't drink a pint of.

B and D were extremely close together for me and I rated B a 9 and D an 8 overall. I picked B as the best as it was the most close to a Genesee

Sample	Aggregate of comments
A	Diacetyl, This was my favorite, Something off with this not sure what, This does not taste good, diacetyl, too sweet.
B	Clean and Crisp, Acetaldehyde, Hop character highest in this one.
C	Low DMS. This is best
D	Cleanest. This tastes the best

I do not have anything but a borderline useless anecdote/speculation to add to this thread. I tend to brew with strains are known to produce more H2S than other strains, including Kolsch, Witbier, Hefeweizen, Augustiner Lager, etc. Some of these I have brewed more than once, and I have observed that a phase I went through obsessing over trub exclusion going into the fermentor anecdotally* (take with several grains of salt) led some of my most "farty" beers. Excluding trub should not, on paper, limit the amount of solubilized cysteine and methionine in the wort from mashing, so I am not sure what in the trub is having the beneficial effect on yeast nutrition and mitigation of this off-flavor, but I have switched to whirlpooling and resting a short time such that a certain 'non-zero' amount of trub makes it into my fermentor, and it seems to result in healthier fermentations coupled with the use of yeast nutrient.

Yeah, I'm speculating that you'd want to whirlpool and settle for a short time for the heavier hop particles to be rejected but you wouldn't want to wait like 30-40 minutes for EVERYTHING to settle out.

 

[corncob]

What struck me most, is that what won out was the current best practice pushed on this forum when I started brewing (about 15 years ago). Way before biab. I (like everyone, it seems like) used 3 vessels with a focus on wort clarity in the vorlauf, then dumped everything but the hops into the fermenters.

 

[corncob]

Since returning to the hobby almost 2 years ago, with no equipment, I have been biab. The thing I love about it the most is the short brew sessions. I hate to think about opening up my crush--it would add a half hour.

On the other hand, I already use a hlt. I have been thinking about a 2 vessel. This might nudge a reasonable man who isn't completely happy with biab in that direction.

 

[doug293cz]

What struck me most, is that what won out was the current best practice pushed on this forum when I started brewing (about 15 years ago). Way before biab. I (like everyone, it seems like) used 3 vessels with a focus on wort clarity in the vorlauf, then dumped everything but the hops into the fermenters.

Don't know about that. My impression from years of reading HBT is that the consensus "best process", pushed by many, was clean boil, clean ferment, which came in third here.

Brew on

 

[Agent]

Thanks for doing all that work to vindicate my laziness in using a bottom draining keggle @Bobby_M

 

[VTMongoose]

Yeah, I'm speculating that you'd want to whirlpool and settle for a short time for the heavier hop particles to be rejected but you wouldn't want to wait like 30-40 minutes for EVERYTHING to settle out.

So the phase I mentioned above was one I went through right after you bent that piece of wire mesh into a circle and I jammed it into the bottom of the Brau to use as a trub dam, ultimately replacing the idiotic mesh filter they equipped it with (side note, I'm glad we didn't weld it in because having it removable makes it way easier to clean).

I had talked to other members of the club at the time who convinced me that "more clear = more better" when it came to wort production. I would whirlpool/chill, pull chiller, whirlpool 20 minutes. Rest 30 minutes, then run off very slowly and leave behind about a full gallon or even better to avoid any chance trub would be sucked in. I also experimented with running everything off, then decanting the beer off the trub the next day when pitching. All of this only had negative effects on my fermentation if any and zero positive effects on clarity.

Nowadays I whirlpool/chill, pull chiller, WP another 2 mins, rest 5-10 minutes, run off full speed and run off everything into the fermentor but the trub pile inside the wire mesh trub dam which is usually still pretty substantial especially if I've done a protein rest or even a low beta rest (where protease and pepsidase still have some low level of activity).

 

[Bobby_M]

Since returning to the hobby almost 2 years ago, with no equipment, I have been biab. The thing I love about it the most is the short brew sessions. I hate to think about opening up my crush--it would add a half hour.

On the other hand, I already use a hlt. I have been thinking about a 2 vessel. This might nudge a reasonable man who isn't completely happy with biab in that direction.

For all the benefits I believe eBIAB has, and there are many, the one pushback that always gave me some pause was the fines in the boil thing. I certainly do not consider this experiment to be conclusive evidence that all BIAB wort is inferior to 3-vessel wort. At best, I'd say there is evidence that there is an upper threshold of mash fines concentration in the boil that seems to be detrimental. Based on evidence of outstanding beers being produced by the BIAB method, I think that many brewers using the method are operating below the threshold. I will likely repeat this fact many times in the ongoing discussion just to be sure people see it and feel it, but the amount of fines in these boils was at least TWICE as much as the average batch.

 

[corncob]

For all the benefits I believe eBIAB has, and there are many, the one pushback that always gave me some pause was the fines in the boil thing. I certainly do not consider this experiment to be conclusive evidence that all BIAB wort is inferior to 3-vessel wort. At best, I'd say there is evidence that there is an upper threshold of mash fines concentration in the boil that seems to be detrimental. Based on evidence of outstanding beers being produced by the BIAB method, I think that many brewers using the method are operating below the threshold. I will likely repeat this fact many times in the ongoing discussion just to be sure people see it and feel it, but the amount of fines in these boils was at least TWICE as much as the average batch.

Oh, I agree 100%. I'm just always thinking about what I might change on my baling wire and duct tape setup if I ever get a chance. I've made very good beer with a wilser bag and almost nothing. Something about the aesthetic of the semi-consumable synthetic fiber bag has never inspired me, despite its utter functionality.

I don't like the idea of stacking vessels, but I've always liked the look of the blickmann false bottom. I like the idea of the bottom drain that you do with those. I think a custom 2 vessel could be compelling. 120v to preheat/mash and propane to boil, since I'm outside anyway. And a decent mill to get the traditional crush.

A system like that would add 30-60 minutes to my brew day.

 

[CascadesBrewer]

The video is up. I ended up calling this experiment #1 because I never really published any data on the first one and I kind of screwed it up anyway.

Great experiment.

It would be cool to see an overall ranking done in opaque cups. I wonder how much the clarity of D pushed it up its Overall scores. Did you happen to try these in opaque cups? Do you think you could tell differences by taste or aroma alone?

 

[Bobby_M]

Great experiment.

It would be cool to see an overall ranking done in opaque cups. I wonder how much the clarity of D pushed it up its Overall scores. Did you happen to try these in opaque cups? Do you think you could tell differences by taste or aroma alone?

There was some discussion way up in this thread about the pros and cons of taking the visual away from the tasting. If the focus was only flavor, that would make sense but everyone drinks beer in clear glasses. How does process affect the beer in the glass with all things considered? I'm not suggesting that the clear vs hazy appearance didn't affect the overall rating. It probably did, because it generally does. I have enough of the beer left to have all the club's judges taste them blind next month and I'll publish that data when it happens.

 

[CascadesBrewer]

There was some discussion way up in this thread about the pros and cons of taking the visual away from the tasting. If the focus was only flavor, that would make sense but everyone drinks beer in clear glasses. How does process affect the beer in the glass with all things considered? I'm not suggesting that the clear vs hazy appearance didn't affect the overall rating. It probably did, because it generally does. I have enough of the beer left to have all the club's judges taste them blind next month and I'll publish that data when it happens.

Yeah, not questioning the process for this round. I tend to think that factors like appearance and fermentation performance are valid factors that should be taken into account. I am more curious if the impact of the Clean Boil is more a slight reduction in haze or actually makes a perceptible impact on the character of the final beer. It would be great if you collected and shared that data.

I have been brewing BIAB almost 5 years. My process is often not much different than your DBDF batch. Sometimes my beers drop crystal clear quickly, and sometimes they hang on to a bit of haze that takes several weeks to drop out, though they do tend to be more clear than what many of my friends make.

 

[Bassman2003]

Thanks for the great experiment and video Bobby. However anecdotal, tests like these push the conversation forward while possibly washing away some dogma. With my pursuit of low oxygen brewing, I have gone very far into the clear everything camp. The sad thing about homebrewing compared to pro brewing is that we do not brew often enough to really see trends and fix them. I have had some fermentation challenges with lagers but lag time was not the issue. I am totally sold on clear wort into the kettle. The use of Brewtan-B in the mash helps this even more. I am a little more open on less clarity into the fermenter, but I pause when it comes to stale flavors for longevity and yeast repitching.

Since going down the rabbit hole, I have noticed every beer has a more "clear" flavor. Meaning less mud. I have to attribute some of this to focusing on clarity through the process. If the difference is throwing in some yeast nutrient vs carrying over trub, I think I would still choose the yeast nutrient until more testing was done. Logically, the idea of just clear wort and yeast sounds like it would produce the more natural beer. But like you said, it is best to follow the data.

 

[mashdar]

It's also interesting that your results align with the much maligned Brulosophy Exbeeriment showing a net benefit of trub in the fermenter when it comes to finished beer clarity, and subtle differences in taste with some tasters preferring the high trub beer, and some preferring the low.

The result doesn't seem particularly surprising, though. Dumping a bunch of cold break into the fermenter is almost the same as dumping a bunch of gelatin in. (Especially if kettle finings were added.) Precipitating protein complexes tend to agglomerate with whatever's at hand. I'd be more worried about head impacts if you lose too many small proteins.

In the vein of another hot thread, I wonder if some of the improvements are due to Zn in the trub.

 

[Bobby_M]

Thanks for the great experiment and video Bobby. However anecdotal, tests like these push the conversation forward while possibly washing away some dogma. With my pursuit of low oxygen brewing, I have gone very far into the clear everything camp. The sad thing about homebrewing compared to pro brewing is that we do not brew often enough to really see trends and fix them. I have had some fermentation challenges with lagers but lag time was not the issue. I am totally sold on clear wort into the kettle. The use of Brewtan-B in the mash helps this even more. I am a little more open on less clarity into the fermenter, but I pause when it comes to stale flavors for longevity and yeast repitching.

Since going down the rabbit hole, I have noticed every beer has a more "clear" flavor. Meaning less mud. I have to attribute some of this to focusing on clarity through the process. If the difference is throwing in some yeast nutrient vs carrying over trub, I think I would still choose the yeast nutrient until more testing was done. Logically, the idea of just clear wort and yeast sounds like it would produce the more natural beer. But like you said, it is best to follow the data.

I think it's easy to slowly convince yourself that efforts are worth it, especially if you spend any money. I was pretty confident that the CBCF was going to be a better beer.

 

[Bassman2003]

I agree. We are all slow boiling frogs!! I thought the same thing but when I step back and think what is happening here, it appears to be a yeast nutrition thing. For me, the tasting was the major part of the experiment. Beer clarity is achieved in many forms but taste is either there or not. It would stand to reason that the trub is giving the yeast something that it needs/wants resulting in a better ferment & tasting beer.

The low oxygen/clarity nut folks add zinc to the fermenter and or yeast nutrients. They/I have also learned to add a lot of oxygen for the yeast. The idea being to strip away everything that is negative and if necessary, add in what is needed. Imho, ferment quality=flavor. So I would say the dirty fermenter had a better ferment.

 

[balrog]

Have we just started the Dirty Fermenter subreddit?

 

[Bobby_M]

The low oxygen/clarity nut folks add zinc to the fermenter and or yeast nutrients.

I wonder what the flavor impact of the nutrient is. I mean directly, not via its utility on yeast health.

 

[Bassman2003]

I would hope zero impact on flavor...

 

[DavidWood2115]

I wonder what the flavor impact of the nutrient is. I mean directly, not via its utility on yeast health.

If you are adding just zinc, it's hard to imagine you could taste it. The recommended dosage is only 300 ppb.
https://www.homebrewtalk.com/threads/zinc-usage-amount-for-healthy-fermentation.732186/

 

[corncob]

I work with data a little in my day job--not usually data reported by people, but it's not miles different.

It would be reasonable, depending on how you frame the question "what does this indicate?" to interpret this data as inconclusive. One gripe many have with the brulosophy guys is their misuse of statistics, which is real. But the idea of assigning a threshold for declaring demonstration of difference is valid, even if the execution is faulty or inconsistent. Without getting a crack at the raw data, and without having any other reference points, it is probably reasonable to say that this test showed little or no difference between the methods tested.

 

[Bobby_M]

I work with data a little in my day job--not usually data reported by people, but it's not miles different.

It would be reasonable, depending on how you frame the question "what does this indicate?" to interpret this data as inconclusive. One gripe many have with the brulosophy guys is their misuse of statistics, which is real. But the idea of assigning a threshold for declaring demonstration of difference is valid, even if the execution is faulty or inconsistent. Without getting a crack at the raw data, and without having any other reference points, it is probably reasonable to say that this test showed little or no difference between the methods tested.

I accept that many academic endeavors do not track with common sense at all. Can you explain how this doesn't clearly show that beer D was better than beer A? Zero people rated A an 8, 9 or 10 but Five people did for beer D. Conversely beer A received 7 ratings of 1, 2, or 3 while beer D received no ratings that low. I'm open to better understanding.

 

[corncob]

I accept that many academic endeavors do not track with common sense at all. Can you explain how this doesn't clearly show that beer D was better than beer A? Zero people rated A an 8, 9 or 10 but Five people did for beer D. Conversely beer A received 7 ratings of 1, 2, or 3 while beer D received no ratings that low. I'm open to better understanding.

View attachment 863217

To do it by the book you would have to show (using more data and analysis) that the differences in the datasets you have are meaningful, given the normal variation in this data. Basically: what if you repeated this test 9 more times--same beer, same tasters, the whole thing, and compiled all the data? How certain are you (based only on this one test) that the big data set would look identical to this one? That question is what the father of statistics was asking himself when he was looking at data from batches at the Guinness brewery.

In not saying this test is not indicative of anything real we can take away--it definitely is useful. I'm just saying that it's not "statistically significant." we would be hasty to toss out our brew bags and corona mills based on this test alone. On the other hand, when compiling this with other anecdotal data we possess, a somewhat clear picture is emerging. It would not be wise to dismiss this.

Statistics is a very divisive tool. It's actually only useful for a very narrow set of tasks, but only people on the inside know that. So numbers are abused and used as cudgels to batter the laymen and fleece the sheep. Do not ever trust a number you didn't calculate yourself. Point of fact: "statistically significant" never, ever means the same thing as "true"

 

[mashdar]

I don't think we're looking for a statistically significant result; it's possible the raw data achieves this (and I'd be intrigued to poke at the data). Even if it were significant, there'd be enough confounding that you could keep moving goal posts.

I'm happy to see the wholistic approach, as I'm sure that's much more fun for Bobby. I'd trade some statistical wizardry for more trials; the latter sounds much more interesting.

(My biggest gripe with Brulosophy is when they claim to have confirmed the null. Lack of evidence is not evidence of lack. edit: but I appreciate their work nonetheless)

 

[doug293cz]

I'm just saying that it's not "statistically significant."

This is an absolute statement. What statistical test(s) did you use to determine this? Please show your work.

Brew on

 

[corncob]

This is an absolute statement. What statistical test(s) did you use to determine this? Please show your work.

Brew on

Hey I'm not the one making a claim. You got me all wrong.

I ain't seen nothin.

I don't know nothin.

 

[doug293cz]

Hey I'm not the one making a claim. You got me all wrong.

I ain't seen nothin.

I don't know nothin.

Um, I quoted directly from one of your posts. You don't get to say that you didn't say what you are on record as saying.

Brew on

 

[corncob]

Um, I quoted directly from one of your posts. You don't get to say that you didn't say what you are on record as saying.

Brew on

I retract the statement. I yield. You win the internet today.

 

[Bassman2003]

I don't think it helps to pick apart the statistics when Bobby said up front that this was a casual experiment/test. It discourages people from putting in the effort to do things like this. Seriously. Corncob, I am not trying to tear you down, what you said is probably true but I think a little bit of a filter might be a better approach. If you do not like the data, either put the effort in and make your own video & test or just let it pass. What this test showed is that there is a difference to people in the tasting and by Bobby himself. How much weight that holds for each of us is up to the reader.

If you were in person I do not think you would have given the statistical analysis. I am on a crusade for some more respect and manners on the internet. It takes a lot of time and effort and willingness to offer something to do a multi-week test like this. I get the impression that true statistics are kind of a mythical absolute that is almost never reached. It is a homebrew test and just don't squeeze the bag. Sorry and please carry on with your insightful posts...

 

[marc1]

I accept that many academic endeavors do not track with common sense at all. Can you explain how this doesn't clearly show that beer D was better than beer A? Zero people rated A an 8, 9 or 10 but Five people did for beer D. Conversely beer A received 7 ratings of 1, 2, or 3 while beer D received no ratings that low. I'm open to better understanding.

View attachment 863217

You can put all the individual scores into an online ANOVA calculator for stats. It will compare all the groups against each other. Run it once for the clarity scores and once for the taste scores.

 

[corncob]

Bobby sells biab equipment for a living. The test he graciously put together and graciously documented seemed to indicate that biab might tend to produce less than the best beer. By suggesting that the results aren't black and white, I was not not trying to tear our guy down, but to build him up.

I'm not sure anova applies anyway. Multiple testers VS. multiple trials VS. multiple variables. The point I was trying (but obviously failing) to make is that the numbers in this case are only qualitative. It would be a mistake to do a rigorous statistical analysis.

I am a big fan of these kinds of experiments.