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Cold Trub: What Should I Think About It?Personal Background(Read this, only if you want to find out why I bothered to do this)
When I first began brewing, I had spent a far greater proportion of my life in school, than I had actually doing things that mattered-- like solving a problem where the solution wasn’t necessarily at the end of ANY chapter. This relationship is expressed by the famous S:L ratio (School to Life ratio). When this is a very large number, one tends to believe the printed word, and acquiesce to authority (which are-- after rule #1; which is sitting still for long periods of time, and rule #2; which is taking turns, unless the other person is regarded as being less talented than yourself, in which case you can ignore rule #2-- the main objects of institutionalised learning). Thirsting as much for knowledge about brewing as I was for the actual product , I eagerly imbibed as much of both, as often as I came across them. While I readily admit that I owe a great deal to the authors that I’ve read, I’ve found through brewing and tasting again and again, and repeated trips to The Big Four (This is a personal appelation--It’s sort of like the World Ice Hockey Championships-- you know beforehand that it only really involves six nations-- when it comes to the World Beer Championships, I’ve always considered the Czech Republic, Belgium, England, and Germany as the "finalists") that each author’s particular prejudices might have, well, let’s say a different emphasis than what I have found to be important factor’s in producing a good beer. Mostly I’ve discovered this by blindly believing every thing I’ve read, and then at some point putting it to the test, when I suddenly find out I’ve been pedantly practicing some irrelevant nonsense. As my S:L ratio excedes "1" I find myself approaching information from a completely different angle-- more of a: "Hmmm, well could be." or "Boy, I sure wouldn’t bother with that if I didn’t have transportation and storage worries." to a "Now I seriously doubt THAT!" or even a "HAR-DEE-HAR. YOU’VE GOT TO BE KIDDIN’. HO-HO-HO." This, instead of immediately running out and modifying my brewing set-up as I once would have done. My main influence the last several years has either been by the generous information offered by personal discussions with real brewmasters (not weekend warriors like myself) or what I’ve figured out by myself, or one of the other brave stalwarts of Bergslagen have stumbled across during brewing. Imagine my surprise, when I connected up to the WorldWideBrewnet in November of ‘96, and browsed several years of HBD, and other fine sources, and found this tendancy toward super oxygenated trubless fermentation. Repeated exclamations that this was the only way to go to make fine tasting beer. I thought to myself "Yeh, sure, that’s the way they do it in the industry, and I think I know why, and it mostly has to do with predictably short turn-around times and economy of materials, rather than making good beer-- In fact, I’ve seen some systems where they REALLY have a handle on that. It was at, let’s see now, YEH, that place where the beer tastes kind of insipid! " It seemed to me I’d been through all of that years ago, and decided then that it was a bunch of hooey. But alas, the remnants of my high S:L ratio days came creeping through my subconscious, and I started thinking: "Maybe I’ve missed something here. Maybe I can make even BETTER beer, with attention to some simple revisions."With that in mind dear reader, I have dedicated 240 litres to repeating the "cold trub experiments". Whether you appreciate the results or not, I hope you at least appreciate the bottleneck I put in my lagering cellar, and I’d be mighty pleased if someone else would due some similar testing of other "truisms" circulating within homebrewing circles. Some of them just may turn out to be unfounded.
Theoretical Background(Read this if you want a quick summary of the present state of confusion) "Cold trub" is the material that falls out of solution when cooling your wort after the boil. I have addressed this briefly in the not-too-informative article "Proteins and Clarity". As regards the keeping or discarding of it, the ideas are many, and the truth obscure. I’ll try and briefly summarise the pro’s and con’s, and try and put the explanations in some somewhat everyday language.
What Some People Say Is Good About Trub:1) It provides a yeast nutrient: The trub contains lipids for sterol synthesis, and perhaps a nitrogen source valuable in yeast replication. This is sort of a "helps build strong bodies twelve ways" argument-- trub is a piece of fatty meat, that provide another food source instead of restricting them to a high carbohydrate diet-- It could be of particular importance if "under pitching" or pitching a starter that’s not at it’s metabolic peak. 2) It provides nucleation sites: The colloidal nature of trub provides channels for the dispersion of carbon dioxide, thereby avoiding toxicity. Essentially, this means it provides a sewage system so that yeast don’t get asphyxiated by there own flatulence (And I’m sure NONE of you would like to be responsible for THAT happening). 3) The products of trub metabolism provide essential products for full lagering flavour. This is self explanatory, and probably empirically determined, the theoretical basis descendent from Never-Never Land. Surprisingly, probably the only postulate of any relevance and testable by the home brewer.
What Some People Say Is Bad About Trub:1) The byproducts of trub metabolism do not leave desirable tastes and are a particular problem with regard to stability. The big ugly finger is pointed at the lipids here, and particularly with regard to auto oxidation. The thought is that the tastes are not nice to start with, and turn into "rotten butter" with time. Diametrically opposite, and the same hindsight rationale as point #3 above. Well, there you have it! Three to one! No sense going any further with this--Trub wins! Actually the crux of the matter to me is what influence it has on the taste. Being a home brewer, and not having to have my primary fermenter available for the next batch at 2:00 P.M. tommorrow, I can always figure out a way to tease my yeast into doing their job (I’ve found that written contracts, where I solemnly promise that I won’t lock them into an air tight room with a bunch of their neighbors after they’ve been acting as tasting judges at the "Saturday Night Baked Bean Competition" works pretty well). I thought I would design a set-up where all the standard trub affecting techniques were tested. What I’ve done is what I call "Parallel Brewing". In order to elliminate the vagueries of home brewing, I try and vary just one thing within the same brew. I find this gives me a much better understanding than varying within successive brews (serial brewing), not only because several other variables might slip into my shoddy home brew set-up, but I can side-by-side taste the results at the same stage of maturation.
What I Did and Why.(This is sort of the "materials and methods" part, and might be a good idea to read if you want to critically evaluate the results. If you don’t care, just hop over this.) I have gathered that the means most people have been affecting cold trub content, are either through 1) the choice of immersion or counter flow cooling, or 2) by racking from the primary either before or during fermentation. In Brew #1, I brewed a very light lager. 70% pilsner malt and 30% bavarian lager. The reason I chose this recipe is that it is one that is quite familiar to my taste buds, and that I find that the lighter lagers tend to make better "sounding boards" for foreign flavours (You might well hide one of my dirty socks in a glass of sweet porter, and I might not notice it for the first couple of swallows). Hopping was done with Northern Brewer, a bit of Hallerau, and a strong Saaz finish. All hopping was reduced by about 20-25% from one of my standard brews so as not to be a dominant part of the flavour. The first third of the brew was captured after boil solely through a counter flow cooler. This was labled "Extra Trub", as the cold break was actually taking place in the cooler, and no attempt was made to remove it. After this,the immersion cooler was turned on, causing a cold break in the boiler, to filter through the hop bed on the false bottom. This was "Regular Trub". After each vessel reached high krauzen, half of the "Regular Trub" was racked from the top into a separate fermentation vessel, doing a lot of splashing. This is a method I have read that people were doing, and I really think has more to do with reoxygenating than trub separation, but what the hell, an experiment is an experiment. I called this one "Dropped", since I think this is what is really going on. In Brew #2, I changed the recipe to 90% pilsner and 10% light munich--I still wanted a light flavoured beer, but, hey! Ya’ can’t drink the same brew for months on end! In this brew, both coolers were employed (the immersion for a fast cold break and hop filtration, the counterflow to rapidly bring near fermentation temperatures. In all cases 16°C was considered acceptable). A third was collected by itself (ol’ "Regular Trub"), the other two thirds separately. Nothing was pitched immediately, but after 24 hours, the top half was gently racked off the 2/3 portion, without splashing, into a separate fermenter and then all three pitched. I think this method provides a true trub separation without oxygenating, so I now have "Regular Trub", "Double Trouble" (half of the clear wort having been removed), and "No Trub". All brews were fermented with Huerlimann Lager yeast from Switzerland at 5°C (41°F) in the primary, and 0.5°C (33°F) in the secondary. Samples for tasting were artificially carbonated in the keg, in order to reduce further taste effects from a new fermentation.
Now, How to Measure What’s "Good"Single blind tastings were performed on three occassions. Being a "taster" required strict criteria. It was required that one had travelled in Europe and tasted the "Classic Greats", and that one was a homebrewer. Pretty stiff roles to fill, but fortunately not difficult to recruit locally. In other words, I was not interested in a "marketing survey", but simply which taste characteristics appealed to the true knowledgable beer enthusiast. Brew #1 was tasted on two occasions, once when still lively fermenting, and once after lagering out. I made this decision because of recognizable taste characteristics which I knew from experience were going to change during lagering. Since I was continually going down there applying my eager lips to the taps, I was not part of the tasting, being quite able to distinguish between them and therefore only "blind"after about 11:00 P.M.. At each tasting, three beers were sampled out of opaque containers (O.K., plastic mugs), and the taster was asked to simply rank them in order of preference, and give any descriptive comments of taste characteristics applicable. Between tasting one and two (both with Brew #1) a random generator was applied to change the tasting order (O.K., I tossed a die). The results were initially confusing, and I thought I might present them as a chi-squared,least squared fit, dubble whammy analysis, but decided instead to simply present them as "most favourite" and "least favourite", and the percentage of votes for each.
The Results (ta-da)All results presented in order of increasing "cold trub" content. Brew #1 (green)
Brew #1 (lagered)"Dropped" most favourite= 17% least favourite= 40%
Brew #2"No Trub" most favourite= 0% least favourite= 60%
Conclusions:Conclusions? I think it would be just a wee bit brash to draw any conclusions from this crappy little experiment and this "enormous" sample size. One of the marvelous (and somewhat spooky) things about brewing, is how many things can effect the taste. With another yeast, fermenting temperature, or beer style, I’m not sure the results would be at all the same. What we do have here is some INDICATIONS. What is indictaed here, is certainly not that cold trub removal makes a better tasting beer. In fact it kind of looks like, lo and hehold, that a higher cold trub content is actually preferred!? Score one plus point for the homebrewer, and one minus for the modern industry. I have not attempted to answer the "hardiness" of these parameters. If you are making a beer that is getting thumped around on the highway, in a bottle that has inevitably had a little oxygen introduced, to be stored at varying temperatures, without the benefit of the best antioxidant available (living yeast)--Then, I think you have a lot of legitamate concerns that aren’t answered here. You might have noticed at this point, that I have assiduously avoided any specific taste descriptions. I have a large collection of my own (and the taster’s), if anyone is terribly interested, but I think they would just confuse the issue here. Perhaps the wisest comment given was not given in chemical terms, or traditional taste describing terminology, but simply: "Which one’s the best? Well that’s different at different times isn’t it? I think I’d like that one (pointing at "Dropped"), if I was going to have a beer after coming home from a long, sweaty, run. I think I’d like that one (pointing at "Extra Trub"), if I was going to sit around a table with a bunch of friends, talking nonsense." ... There you have it..."Running Beer" and "Talking Beer". Perhaps the descriptions needn’t be more complicated than thus. To answer the question of whether cold trub is good or bad, I’d say neither. It has a definate taste profile that you may or may not like in a particular beer. I’d suggest doing a little "parallel brewing" yourselves, to identify that taste and decides its appropriateness in each one of your brews. That is after all the advantage of being a homebrewer. You can tailor your brew exactly, and include tastes that a commercial brewery wouldn’t dare because of transport and storage problems. As for myself, I’ve got to get my Easter beer together. I’ve decided the malt and hop profile, I think I just need a bit of, yeh, that’d be perfect. Problem is my counter flow cooler is just too slow by itself...Any body know where I can buy some good used trub? |
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