Author: Marshall Schott
One of the cheapest and most often recommended ways to increase the likelihood of producing a clear beer is by adding a teaspoon of a red marine algae known as Irish moss to boiling wort in the last 5-15 minutes. If you’re like me, using Irish Moss or a similar carrageenan-containing kettle fining occurs as a matter of course, purchased by the pound and used in every batch without hesitation. I hadn’t really considered how exactly Irish moss works until a recent brew day when, after adding some to boiling wort, I watched the chunky clumps of protein form almost immediately, something I’d witnessed hundreds of times before. I immediately thought about the fact Irish moss is referred to as a kettle fining, meaning it’s used to produce clearer wort, which made me wonder if it had any impact during fermentation. And what about the results of the trub xBmt where more kettle trub in the fermentor produced the clearer beer? I hit the interwebs and found a plethora of articles on Irish moss including one from the AHA titled Take the Luck Out of Clear Beer With Irish Moss, which explained:
A majority of the Irish moss plant consists of carrageenan, which is key to clarify beer during the boil. Carrageenan has a negative electrostatic charge. Protein clumps from the boiling wort’s hot break are positively charged. Because of the attraction between proteins and carrageenan, larger clumps of hot break material form, making them more likely to precipitate out of suspension in a faster manner. Ultimately the clumps will not make it into the fermenter. (John Palmer, September/October 2003 Zymurgy)
Aha, I wasn’t totally wrong! The sole purpose of Irish moss is to make it easier to rack clearer wort to the fermentor, which presumably leads to brighter beer based on the axiom, clear wort leads to clear beer. Since this didn’t totally jibe with my personal experience of transferring trub-ridden wort to the fermentor, I started questioning how big of an impact Irish moss actually has and decided it best to put it to the test.
But first…
I am certainly not the first to experiment with Irish Moss. In the 6/10/2010 episode of Basic Brewing Radio, James and crew discussed the results of their own BYO/BBR collaborative experiment that seemed to suggest a fairly significant observable difference in clarity when compared to beers made without the fining agent. However, the results of listeners who performed their own experiments were more mixed, with some going as far to say Irish moss is a waste of money. Additional research led me mostly to concerns about the flavor impact of using too much Irish moss and speculation that its use reduces head formation and retention. Agog was I!
| PURPOSE |
To investigate the differences between a beer fined with Irish moss and one that was not.
| METHOD |
I had been chatting with my buddy and Brulosophy contributor, Ray Found, about American Red Ales, as style I enjoy but haven’t brewed in some time. I thought it’d be a fine style for this xBmt and threw together the following recipe.
American Red Ale
| Batch Size | Boil Time | IBU | SRM | OG | FG | ABV |
|---|---|---|---|---|---|---|
| 11 gal | 60 min | 33.4 | 13 | 1.063 SG | 1.014 SG | 6.5 % |
Fermentables
| Name | Amount | % |
|---|---|---|
| Domestic 2-Row | 15 lbs 15 oz | 72.6 |
| Gambrinus Munich 10 | 3 lbs | 13.7 |
| Crystal 10 | 1 lbs | 4.6 |
| Victory Malt | 1 lbs | 4.6 |
| Crystal 120 | 8 oz | 2.3 |
| Pale Chocolate Malt | 8 oz | 2.3 |
Hops
| Name | Amt/IBU | Time | Use | Form | Alpha % |
|---|---|---|---|---|---|
| German Magnum | ~17 IBU | 60 min | Boil | Pellet | 12.2 |
| Willamette | 60 g/6.5 IBU | 15 min | Boil | Pellet | 5.4 |
| Centennial | 80 g/8.4 IBU | Flameout w/ 15 min stand | Boil | Pellet | 9.9 |
| Willamette | 60 g/1.9 IBU | Flameout w/ 15 min stand | Boil | Pellet | 5.4 |
| Centennial | 30 g in each fermentor | 4 days | Dry hop | Pellet | 9.9 |
Yeast
| Name | Lab | Attenuation | Ferm Temp |
|---|---|---|---|
| SafAle US-05 | Fermentis | 76% | 58°F |
Despite my opinions of the Chico strain, I chose to use US-05 for this xBmt because, well, it’s the most popularly used strain in the universe and hence I believed it might be the most applicable. I also happened have a couple fresh sachets lying around that I wanted to use up.
Since manipulation of the independent variable in this xBmt would occur during the boil, I thought it might be fun to try a novel (to me) approach when it came to brewing this beer– rather than perform separate mashes, I would mash a single batch then split the resultant wort into 2 kettles. Utilizing the batch sparge method, I got to mashing.
After an hour, during which I stirred the mash a few times for efficiency’s sake, I collected the first runnings of sweet wort.
A measured amount of 175°F (80°C) sparge water was added to the grains, stirred, then the second runnings collected and added to one of my 14 gallon kettles.
I stirred the single volume of sweet wort for approximately 5 minutes to ensure complete homogenization of the first and second runnings, after which I collected half and added it to my other brew kettle.
I checked the SG of each wort 3 times to make they were the same, which they were. The boil proceeded as usual with hops being added at their scheduled times. I used my precision blade scale to weigh out 5 grams of Irish moss, which is equivalent to approximately 1 tsp, the recommended amount for a typical 5 gallon batch of homebrew. The Irish moss was then added to one kettle with 10 minutes left in the boil, while the other kettle received none.
Using the King Cobra IC with my wonderfully cool groundwater (58°F/14°C), I chilled each batch to my target pitch temp in under 4 minutes, allowed them to sit for about 10 minutes to keep things as fair as possible, then racked them to 6 gallon PET carboys. Rather than immediately move the fermentors into the temp controlled chamber as I usually do at this point, I set a timer for 10 minutes to intermittently document any observed differences.
I always trusted Irish moss had some sort of coagulative effect, but honestly, the differences I observed surprised the hell out of me. After pitching yeast and moving the carboys to the ferm chamber, I collected some of the leftover wort in hydrometer flasks and let them sit out while I finished cleaning up. As predicted, the Irish moss batch was noticeably clearer with a much thicker trub layer than the non-fined sample.
Both beers were fermenting nicely just 12 hours post-pitch.
I came back a day later to discover a fairly drastic difference in the way each krausen looked, with the Irish moss batch much more recognizable than the other.
The brownish layer on the non-fined batch persisted for about 1 more day, after which both beers took on a very similar appearance. I bumped the temp to 70°F to encourage complete attenuation, taking an initial FG sample 1 week post-pitch; specific gravity was the same for both.
The beers appeared to be of equal haziness at this point.
I let them hangout in the warm chamber for a few more days, both ultimately finishing at 1.014 SG. While I’ve made it standard practice to fine my beers with gelatin, I forwent this step due to the overwhelming preference expressed by Brülosophy readers on a recent survey.
I crashed the beers to 32°F for 3 days prior to being kegged, a tad longer than usual due to the fact I didn’t fine with gelatin.
After a few days in the keezer, they were ready to be served and I was awkwardly excited to observe the changes in clarity that might occur over the time they remained on tap. What follows is a temporal look at the beers over a course of about 5 weeks, the one fined with Irish moss is on the left in each one.
You may have noticed slightly less haze in the Irish moss beer starting at about week 3, though to be fair, it took a lot of finagling to get the proper lighting and angle to achieve these results. The only consistent difference I noticed in appearance, starting from that first pour, was the head retention.
The beer fined with Irish moss actually seemed to produce a creamier and stickier foam than the non-fined batch, which I found pretty interesting, as it’s the exact opposite of what I’d heard.
I decided to give these beers more conditioning time than I usually do before presenting them to the tasting panel, spending 4 weeks in my keezer before data collection began.
| RESULTS |
I was invited to chat with James 
Spencer about this xBmt on an episode of the fantastic Basic Brewing Radio podcast, it was a great time. Cheers to Olan from HomeBrewDad.com for taking the time to evaluate these beers as well!
I convinced a total of 15 people to participate in this xBmt, each was served 1 sample of the Irish moss fined beer and 2 samples of non-fined beer in different colored opaque cups then instructed to identify the unique sample. In order to reach statistical significance, 9 tasters would have had to accurately select the odd-beer-out, though only 8 were able to so so (p<0.05; p=0.09), indicating participants in this xBmt were unable to reliably distinguish a beer fined with Irish moss from one that received no kettle fining.
Prior to analyzing the data, I was convinced I’d discover that the majority who correctly chose the different beer would also report appearance as being noticeably different when comparing only the 2 different beers. Nope, 6 of the 8 correct respondents (75%) perceived appearance between the beers to be exactly the same. The only 2 participants who perceived the appearance to be different were James and Steve from Basic Brewing Radio, both endorsing the beer fined with Irish moss as having better appearance. But even James admitted they almost missed it. Initially, this made me wonder if perhaps some of the blind participants simply paid less attention to appearance than the others. If this were the case, and given the fact significance was nearly reached, one might assume some other factor contributed to the perceived difference between the 2 beers. Let’s have a look!
When it comes to aroma, 3 and 5 of the participants said the beers were not at all and somewhat similar, respectively. Huh. Every person who correctly chose the different beer during the triangle test experienced the 2 different beers as being aromatically distinct. In terms of preference, it was split down the middle, with 4 each preferring the Irish moss and the non-fined sample. Ratings on flavor similarity were slightly different with 6 tasters perceiving the 2 samples as tasting only somewhat similar while the other 2 perceived them to be not at all similar. Furthermore, 5 preferred the flavor of the non-fined beer, while the other 3 thought the Irish moss batch tasted better. Still, no one perceived them as being the same. Regarding mouthfeel, 5 thought they were somewhat similar, 2 reported them as being exactly the same, and only 1 perceived them as being not at all similar. When asked which beer was preferred overall, a small majority (5) selected the beer that was not fined with Irish moss.
Toward the end of the survey, participants who accurately chose the different beer in the triangle test were informed of the nature of the xBmt and asked to pick the beer they thought was fined with Irish moss. I was certain at this point, the beers slightly warmer and each person knowing the variable being tested, everyone would be able to pick the correct beer. Again, I was wrong– 3 people incorrectly chose the non-fined beer.
My Impressions: I sampled these beers side-by-side more than I usually do xBmt beers only because they were on tap so much longer than usual, I couldn’t smell or taste a difference at all. My impressions on what I observed in terms of clarity are best summed in the photos above– the Irish moss beer was clearer than the non-fined batch, though not by much. I’m compelled to believe the differences reported in flavor, aroma, and mouthfeel by participants are a function of expectation bias, at least to some extent. But perhaps I’m wrong, perhaps my inability to perceive those differences has more to do with my shitty palate, perhaps Irish moss really does have an impact on characteristics other than clarity. I don’t know.
| DISCUSSION |
From a strictly statistical standpoint, these xBmt results suggest Irish moss does not significantly impact beer. From a purely observational standpoint, as you can clearly see in the photos above, the Irish moss beer did eventually develop better clarity than the non-fined beer. The fact the very characteristic Irish moss is purported to affect, appearance, is the only one the majority of tasters agreed was exactly the same as the non-fined batch fascinates me, but not because I believe each person’s observations were accurate. I don’t. I’m actually of the opinion participants simply didn’t pay that much attention to appearance, both beers looked “similar enough,” and hence this xBmt was the final push for me to make a change in the way I approach data collection. From now on, participants will be served each sample in opaque cups, an idea I toy’d with before and recently learned is the way it’s done on a professional level.
Nearly every brewer I know uses either Irish moss or Whirlfloc on the belief it will increase the clarity of their beer. At this juncture, I’m fully comfortable saying it may not be necessary, though it would appear to have some impact. I mean, how many times have you forgotten to toss Irish moss into the boil only to end up with perfectly clear beer a few weeks later? I absolutely plan to repeat this xBmt using gelatin to fine post-fermentation and, should the results be as I expect, I’ll likely ditch the practice of using Irish moss altogether. In fact…
Once the data was collected for this xBmt, I thought it’d be fun to play around with gelatin a little bit. This was admittedly uncontrolled, observation-only, fully biased, and totally anecdotal. I transferred the 2 or so gallons from the non-fined keg to the Irish moss keg, which had a similar volume remaining, added the gelatin solution, and pulled a sample just a couple days later.
The beer tasted as I remember it– slightly toasty, slightly roasty with a noticeable caramel malt note that didn’t overwhelm the Centennial hops. I won’t be brewing this beer again, not that it was terrible, I just didn’t like it all that much. Had I fermented it with a different yeast, something like WLP090, it’s possible I would have formed a different opinion.
What do you think? Have you experimented with kettle finings? Maybe you’ve never used Irish moss and your beers always come out bright. Whatever it is, please share your experience in the comments section below. Cheers!
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57 thoughts on “exBEERiment | Impact Fining With Irish Moss Has On An American Red Ale”
I have always used Irish Moss out of habit, so this was an interesting read. Additionally, I have heard around the interwebs that Irish Moss performs better if you hydrate it before adding to the boil kettle.
A have a few (probably not that interesting) comments!
1. I use 2.5g of Irish Moss per 5-gallon batch (the amount I weighed a tsp as using a blade scale). I found this interesting being that you weighed it as 5g. I can’t image the suppliers are that different.
2. I wet the Irish Moss with a bit of the wort from the kettle before adding. Again, following my old wives tale above. I have no empirical evidence to suggest this is helpful.
3. I don’t use any other kind of fining, but I do cold crash at about 34°F for 2-3 days. My beers are clear enough for me but I certainly haven’t put them through the testing you have here.
Interesting. I will say that 5 grams is more like a heaping tsp and that the actual amount of wort in the kettle is closer to 6 gal, though I’m not sure that matters much.
Ok. That makes more sense. I try not to use “heaping” for any of my measurements because what is heaping to you may be completely different to the next brewer and you really aren’t comparing the same amounts.
I have a feeling when it comes to IM, more isn’t worse.
Also, on my system I sort of go through a double “filtering” by default before it goes to the fermenter. “Filtering” is in quotes because I don’t actually filter, but I whirlpool for about 5 minutes then have a diptube that picks up at the edge of the kettle (leaving most trub behind). This then drains to a cooling pot (a 7.5 gallon pot with an immersion chiller permanently installed). After this cooling, I leave a good amount of cold break left behind.
I’ve been playing around with trub in my fermentors for awhile now and have come to the conclusion I actually prefer the beers fermented with a decent amount of kettle trub, and I’ve yet to experience any off flavors from this.
I have heard that some trub provides nutrients for the yeast. I try to provide the nutrients in the starter and make sure my water chemistry is properly adjusted for healthy fermentation.
That might be an interesting one for future xBmts.
One thing I did not notice you mention is if you re-hydrated the Irish moss prier to adding it to the wort. Do you think it would have made a difference if your results had it been re-hydrated first? I always re-hydrate mine first.
I’ve never rehydrated IM, though I supposed I’ve heard of technique. Still, given how well gelatin works and its ease of use, I’ll likely forgo IM in future batches once I run out of my currently supply.
I’m convinced: no irish moss, yes gelatin. You are the Socrates of homebrewing.
“The only true wisdom is in knowing you know nothing.”
Cheers, buddy!
It is possible that The two could work together to produce the clearest beer.
Great experiment. I really appreciate all of the consideration of the tasting results, and trying to get to the bottom of the ambiguities.
In my own experience, I have done a number of side-by-side brews to evaluate effects of the kettle finings, as well as the effects of fermentor trub. While not scientific, and with a very limited sample size of tasters, there has been no clear winner on either clarity, head retention, or flavor characteristics. My current thinking is that irish moss is an obsession that may be useful for those who are addicted to quickening results, but for people like me who appreciate that time and patience is an important ingredient, simplicity is the preferred route.
On a technical side, I have often wondered about the interaction of the positively-charged proteins in the kettle, and negatively-charged particles in the fermentor. Do they impact the fermentation itself, and do they ultimately come together to annihilate each other to ultimately clear the beer more effectively than using a two-step irish moss and gelatin approach? Hmmm.
On a technical side, I have often wondered about the interaction of the positively-charged proteins in the kettle, and negatively-charged particles in the fermentor. Do they impact the fermentation itself, and do they ultimately come together to annihilate each other to ultimately clear the beer more effectively than using a two-step irish moss and gelatin approach? Hmmm.
I have been searching for an answer to this since I forgot to add IM to my boil for a citra PA. I wondered if I could boil some IM and add it cooled to the wort the next day. I was worried though that it might attract the protein in the yeast just as it was starting to grow and then fine it out. This might kill a bunch and lead to off flavours or poor fermentation so I just left it.
I’ve found that most beers I brew drop bright with time. Left to condition on the months scale I’ve got some really clear beer.
I’m interested in a little bit more of a description about your racking from kettles to carboys. Was the IM batch looking more clear as it was flowing through the siphon? What were the differences in the appearance/amount of trub as you were nearing the bottom of the kettles? About how much trub did you end up transferring, especially with the IM batch? I assume a good amount of trub was transferred to the carboy based on the photos.
I allowed each kettle to sit for about 10 minutes prior to racking to carboys. I’m not sure of a good way to measure exactly how much kettle trub was racked to each carboy.
Have you ever forgone the IM and split a batch where 1 was cleared via gelatin then cold crashing and the other via cold crashing alone? I’ve never used any type of fining agent opting to cold crash only and have produced some very clear beers. I have a golden ale kegged now that is so clear I can actually read through it.
I’ve not done a no-IM + gelatin xBmt yet… but it’s coming.
I’ve accidentally forgotten to add Whirfloc or Irish Moss a few times on beers, and they don’t seem to ever turn out much cloudier. It seems to me that adding a yeast clarifier (like gelatin) has a much more profound impact on finished beer clarity than the kettle finings, as your test seems to show. If you add IM and then neglect to drop the yeast (or wait a long time), you are going to have much hazier beer than if you had just skipped the IM and fined the yeast!
Hi Marshall,
Thanks for this new xBmt !
Last batch I boiled, I forgot to add the Protofloc tab, and the beer (a Saison) is… cloudy as hell !
But I don’t give all the credit of clarity to finings, this time I used some rye malt, which I believe imparts some haze to the brew…
Cheers !
When you transferred your wort to the fermenters, how much care did you take in trying to leave trub in the kettle of the Irish Moss’d batch? I’m sure those who swear by the additive are also those who are particular about avoiding the transference of the coagulated solids.
When you retest this xBmt, would you be willing to document the differences between your now-usual “Trubby” wort with no finings and a “filtered & Mossed” batch before and after you add the gelatin finings?
Keep up the great work, I really enjoy learning from your experiences.
I allowed each to sit for about 10 minutes prior to racking and did nothing to encourage the transfer of kettle trub to the carboy. I definitely have plans to do some combined-variably xBmts 🙂
Here’s my theory:
You need to do one things to clarify your beer.
1. Use Irish moss
2. Cold crash for a few days
3. Use gelatin
I think one of those is enough to have an acceptable level of clarity for your beer. Doing two or three doesn’t hurt, but is unnecessary. Since you cold crashed for 3 days, your beer was clear, regardless of the Irish moss.
I’m not convinced all 3 are required, my hunch is gelatin will work as well without IM… xBmt planned!
I brewed yesterday and added Whirlfloc for the first time along with Irish Moss. My carboy at 10 minutes looked exactly like yours on the left in the 10 minute picture. Thick dramatic trub layer. Never saw anything like that before so immediately. If I had a reason to leave it out – it would be that the Irish Moss does stick a bit to the chiller coils. I read elsewhere, by what was said to be an expert, that Irish Moss should be re-hydrated 24 hours before using and that would increase its efficiency a lot, I will post the link if I find it (didn’t try it).
I always use moss and pre-hydrate at least an hour before adding. I’m not looking for super clear beer just want to knock out more break material before putting into the fermenter—of course this has been busted now. But anyway, I did an expreiment where I added an extreme amount of moss like a quarter cup and the results were dramatic. There was no krausen at all during fermentation as the moss continued to knock everything out of suspension, including all my top cropping Essex yeast. When I racked it to the keg the trub on the bottom looked like chocolate cottage cheese. No smooth pack just big ugly clumps of everything stuck together. I killed my Essex that I had been repitching for two years straight—and I was beginning to think it was immortal.
Did the extreme IM beer taste like the ocean?
I have the worst problem with chill haze and neither whirlfloc or irish moss seem to make any difference. When I did BIAB, I had much clearer beer than I do on my new system. My theory is that the floc’d trub from the irish moss/floc tablet must continue to precipitate proteins while inside the fermenter–basically trub in the fermenter is a good thing.
With BIAB, I would end up with a huge, massive amount of trub in the fermenter, while my new system filters most of it out.
On my new system, I do a RIMS mash and which creates crystal clear wort into the kettle, I add the whirlfloc near the end of the boil, followed by a fast whirlpool and 20 minute settle time which results in very clear wort with a large confined trub cone in the center of the kettle. The kettle drains through a very fine braided stainless steel hose that circles the outside of the kettle. Needless to say, I end up with very little trub in the fermenter. I ferment in a conical fermenter, and after fermentation I dump/harvest most of the yeast/trub before cold crashing for two days and finally transferring into a keg through a 1 micron poly filter. At 37F, the beers from my new system, regardless of yeast or grain bill, are very cloudy, almost like a hefewizen. When they are warm, they are amazingly crystal clear. The times I’ve forgotten the floc tablet haven’t seemed to make any difference.
I’ve tried adjusting the amounts and the boil times of various clarifiers, but the chill haze is always there. I haven’t tried gelatin, but based on Marshal’s article on it, I’m ready to ditch the kettle finings all together and go with that instead.
I just used Irish Moss for the first time on my most recent brew, and it came out the clearest I’ve had yet (pre-chill), and clearer (though I wouldn’t say crystal) once chilled.
I’ll probably use up the supply I have, then re-evaluate going forward.
I have forgone the kettle finings and use gelatin exclusively now with good results. My beers are hard to distinguish from commercial brews on a clarity level. So I am looking forward to the next batch of results on gelatin. I have been suprized by them just as much as you have in the past!
On a side note, have you ever done a control by just serving the same exact beers side by side and asked a series of questions about them like a difference in taste, appearance or preference? That would certainly give some variance parameters. Could be fun!
I was under the inclination that adding gelatin to carbonated beer wasn’t a good idea. It appears that that’s not the case. *runs off to prepare gelatins solutions for all beers that weren’t gelatin-ed*.
Worked for me!
Think this would work for a cider? It’s been in a keg for 2 months and still hazy.
I’ve always thought of irish moss as a way of helping to retain break material in the kettle – i.e. you condense it down so it sits in your cone after whirlpooling, and thus doesn’t get transferred. I suspect you may have seen more of a difference had you not carried over as much trub to the fermenters as you did in this trial.
I have always used Whirlfloc and never IM, but this (combined with the trub experiment) has convinced me to quit the Whirlfloc, and just fine with gelatin.
Perfection is finally attained not when there is no longer anything to add, but when there is no longer anything to take away.
-Antoine de Saint Exupery
At ~$2/sack for Whirlfloc it’s a cost I don’t mind paying, even if it is only a minor benefit. The same goes for gelatin finings. I use both, even for dark beers, because why not?
FWIW, Irish Moss needs to be prepared before using, a step most folks omit (though apparently not to much detriment). A few minutes before using you need to rehydrate it with hot water, folks seem to say wort works well too.
Did you consider trying Whirlfoc instead of, or in addition to, the Irish Moss? Maybe the amount of IM used by homebrewers isn’t enough and Whirlfloc would do more?
I used to use Whirlfloc exclusively, it always acted exactly the same as IM and cost way more, hence my return to IM.
Well until this xBmt, you though Irish Moss did more than it did too 🙂 Maybe there is something to a refined version in WhirlFloc that could do more? Or maybe it acts identically?
I was struck when looking at the experiment samples just how dark the ale was and how this would perhaps make it much harder to recognise clarity differences. I have been working on various pilsners for a while now and I see very different levels of clarity quite easily due to the light coloured wort/beer. Perhaps a lighter brew would be more telling if you were to repeat the xBmt.
I find gelatin more important for clear beer than Irish moss. I still use the moss though, I transfer much less trub to my fermenter when I remember the moss. This results in less waste at the bottom of the fermenter when it comes time to package.
You are doing good work getting through all these important questions. Thank you.
What I find very interesting is that if you taste hydrated irish moss, it’s amazing disgusting. I used to chuck it dry into the kettle, then started rehydrating. Haven’t seen any difference between hydrated and dry addition, other than the gag reflex just putting it to my nose. Fortunately it doesn’t follow into the fermenter (as far as I can tell). But – I switched back to Whirlfloc.
Skepticism is healthy! Keep it up!
I use irish moss in all my batches, but I remember one of them in which I forgot to add it. I try to cool the beer after fermentation for three or four days, and in that case I did it too. The beer, finally, was clear enough (as the others with irish moss), so probably cool beer is better option to fining beer than using irish moss, but I haven’t tried to brew two identical batches “with and without” irish moss 🙂
Cheers!
I’ve only noticed a clarity difference in the final beer when I left the fining agent (Koppafloc in my case) out of a couple of beers made with floor malted Bohemian pilsner malt – those definitely have a fine particulate material that never really drops out of suspension, but if I use Koppafloc then the beer is clear. With regular pale malts (Golden Promise/Maris Otter) I don’t really see a big difference. I do rack most of the kettle trub into the fermenter though.
While I don’t use Irish Moss, I do use whirlfloc quite often. One difference I have noticed is that the whirlfloc tends to form very fluffy trub in the fermenter, while the batches without kettle fining tend to have a more compact, but powdery trub. I didn’t see a final picture of the fermenter – did Irish Moss have a similar effect?
You can see an example of what I’m referring to in the following post:
https://www.homebrewersassociation.org/forum/index.php?topic=13403.msg170218#msg170218
The end result seems to be that it is easier to rack clear beer off the kettle-fined beer because the trub clumps up nicely, while non-fined trub tends to get disturbed much more easily. The caveat is that on small batches (in the 1-gallon range) the fluffy trub is enough to reduce your yield slightly since it take up so much more space.
I’ve used both IM and Whirlfloc quite a bit, they seem to perform very similarly if not nearly the same. I didn’t notice any difference in the way the trub looked at the bottom of each fermentor, but my completely uneducated assumption would be that it’s more a function of the yeast used rather than the IM. I’m probably wrong about that.
Great experiment! My feeling is that whirlfloc, irish moss, et al fall under the category of things that are more relevant for pro brewers than homebrewers. Your trub xBmt nicely demonstrated that clear wort != clear beer. However, to pro brewers, clear trub-free wort may be desirable for for other reasons, such as not gunking up equipment and having cleaner yeast for repitching. I also remember reading somewhere that kettle finings can help with beer’s shelf stability, but I can’t recall the source or rationale behind this.
As for me personally, the non-zero effect on clarity and head retention that you showed in this xBmt is reason enough to continue using irish moss in my homebrews. The cost per batch is negligible and it takes no additional effort to use. When I want a crystal clear beer I use gelatin, but otherwise irish moss + the week my beer spends force carbing at ~30°F gets me to a level of clarity that I’m happy with.
in your experiment you mention an observation of better head retention. I feel that I prefer a beer that meets my stereo typical expectations of a good beer, high clarity with good foam characteristics. Does it affect the taste? I have no idea. Does fining in the kettle or the keg affect head retention? This reader would appreciate an experiment in that area. I enjoy reading the articles keep up the good work.
I use a kettle fining called Brewbrite, which is apparently a mixture of Whirlfloc and Polyclar in one. It definitely drops out the crap in the kettle pretty quickly after the boil, but as yet I haven’t really noticed any difference in the end product. Some of my beers come out cloudy, some of them come out pretty clear, and I use the exact same process every batch, so I don’t know. My next batch I’m gonna revisit using gelatin during the cold crashing phase, and see how that goes. 🙂
Cheers
Be prepared for super clear beer!!!
That would be excellent! I commented on my failed use of it last time on another post, but this time at least I know what to do with it.
Completely off topic here, but have you tried an extreme xBmt?
What I mean by this is trying all the xBmts at once (fermentation at room temp, shorter mash time, boil length, etc) in a single batch vs a “normal” batch with the only thing in common being healthy yeast and a good pitching rate. With the purpose of finding out if a good amount of healthy yeast is enough to, let’s say “fix” the wort.
Could prove to be a really interesting xBmt. Thoughts?
Not yet… but stay tuned 😉
I have forgotten kettle finings before. I use whirlfloc normally. Beers enter the fermenter substantially clearer when I use it, but by the time fermentation is done they look no different than batches when I leave it out.
However, when I try to use gelatin to clarify for an extra sparkle, the non whirlfloc batches don’t ever fully clear. The batches where I use it respond much better to gelatin. I don’t know the reason behind this.
I just recently started using gelatin, but I’ve used Irish Moss or Whirfloc to satisfactory results for 2+ years. Well, I skip it on stouts but everything else gets it.
Glad to see this. I was decanting my wort (more or less no-chill, too) into the carboy just now and thought “oh shit” as I realized I hadn’t added Irish moss. I’m also going to ferment with 34/70 at ambient for this Vienna lager. Could it be one of those “do everything wrong” brews some of your readers are always suggesting when they’re surprised at all of your negative results?
Just listened to the new podcast about kettle finings. Did you transfer the trub to the fermenter in this experiment or leave it behind?
Would you and Ray Found be willing to share this recipe and is it available in a *.BSMX or other file? Great experiment although since the outcome is appearance based, not taste based, not sure if the opaque cups would help. Great discussion! Thanks
The recipe is in the article, no?