HOMEBREW Digest #5348 Wed 18 June 2008

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  Phenomenology and beer - pt 1 ("steve.alexander")
  Kettle weight paradox ("Greg 'groggy' Lehey")
  Re: Sanitizers (Tim Runnette)
  Phenomenology and beer - pt 2 ("steve.alexander")
  Fast Ferment Test (Kai Troester)

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---------------------------------------------------------------------- Date: Tue, 17 Jun 2008 23:09:50 -0400 From: "steve.alexander" <-s at roadrunner.com> Subject: Phenomenology and beer - pt 1 It seems Fred Johnson posts some tasty topic whenever I'm in the middle of a travel or a time-crunch. I'm having more than my share of these this year and I'll be missing the Cincinnati AHA this week as a result ... > > Thanks to all of you who have contributed to this discussion. I Let's not put a cork in this one quite yet. Alexandre Enkerli writes > > Well, honestly, as a social scientist and an artist, I can't really > > say I share Fred's frustration over difficult or impossible to measure > > characteristics. [...] > > In fact, I often wonder why it seems important to *reduce* perception > > to measurement, in the case of something which is meant to be enjoyed. > > No offence intended, of course. Fred and others aren't at fault. It's > > just that the perspective puzzles me. The age of enlightenment was among other things an era of careful observation and experimentation leading rather directly to the modern ability to manipulate the physical world. Alan Watts popular writings on philosophy describe "Western thought" (science) as a process of breaking the world into smaller and smaller pieces with finer resolution, but less relevance to the whole. This is true, but he ignores the other half which is science drawing a much bigger overarching "laws" from these tiny fractured observations. One measures the rates that stones and feathers and apples fall, and suddenly momentum, and gravity and the motions of the planets is revealed. We observe the relation of pressure, volume and temperature then sound and thermodynamics are accessible. One makes a few observations about the volumes of gases produced in chemical reactions and suddenly the chemical structure of matter is known. One makes some careful measurements of the speed of light relative to the earth and a deep view of the nature of light, and a complete explanation of magnetism suddenly appears. These sorts of development, from observation to generalization are startling and have had practical import to the extent that modern life (and about 30% of the population) would be impossible without them. So how could it be that reducing observation of sensory perception (or anything else) is not of paramount importance, if we wish to understand it ? It is demonstrably the most successful model for forming an accurate and functional view of the physical world. Sorry - but I find the "anti-science" attitude that prevails in the recent few decades (and I don't think that is where Alexandre was heading) obnoxious. Understanding the causes of a subjective experience doesn't reduce the experience, but it may reveal how to create or extend that experience. As brewers we are clearly producing a "designed" product and so we would like to know how the design relates to the experience. So back to the current puzzle. If anyone cares for an amusing intro .... In sci-fi classic 'Dark Star' an astronaut attempts to disable a smart bomb by teaching it phenomenology. http://www.youtube.com/watch?v=EvcfPVGY-ck Phenomenology need not be so crippling. We take a beer sample and we apply it to a human sample and we elicit a qualitative description. What just happened ? Is it useful ? We have good reason to believe that humans are generally physiologically similar, so they may experience the beer sample with a similar subjective experience. Of course we also have good evidence of wide variations ... many mushrooms for example taste bitter to certain ppl but not others based on their specific genetics. Many ppl (tho' a minority of European descent) are so called "super tasters" with a reported higher density of papillae on their tongues. Certain internal states or combinations of stimuli can result in odd experiences (e.g. certain generally phenolics make tea taste LESS bitter !). Furthermore we can probably never record the subjective sensation directly; tho' EEGs and PET scans are a step closer. We must use indirect measures. We have all learned to utter similar qualitative descriptions(QDs) when the same stimulus is applied. We have learned to say "sweet" in response to sucrose, and "salty" to sodium chloride, but this doesn't necessarily mean our subjective experiences are the same. So we have a mapping from objective stimuli to some subjective experience then back to a QD with some pretty good correlation. That regularity of stimuli->QD mapping is weaker down across "cultures" and varies based on learned results. A group of trained beer judges might all utter "diacetyl" in response to the same stimuli - but an untrained taster might produce an entirely dissimilar QD. Of course the QDs produced are based on experience and local convention; British wine writers like to compare red wines to "cassis", but fresh cassis berries aren't widely available in N.America. N.Americans may describe sunstruck ales as "skunky", but it's unclear how this QD is interpreted in Eurasia. We also have "hedonic scales". A majority of beer judges might frown and downgrade a beer with diacetyl, while others might smile and argue that a certain level is expected in certain styles. We have cultural divides on the hedonic scale - the bland Japanese diet vs the spicier diet of India for example predisposes the preferences of individuals. We have idiosyncratic tastes - some ppl enjoy oxidized wines or other oddities. Children generally reject bitter foods while adults can enjoy these - and this may have survival value. (cont) Return to table of contents
Date: Wed, 18 Jun 2008 17:43:01 +1000 From: "Greg 'groggy' Lehey" <grog at lemis.com> Subject: Kettle weight paradox I've just bought myself a couple of large aluminium stock pots for use as a mash tun and wort kettle. First thing I did was to confirm volumes and such, and while I was at it, calculated the weight of the pot, mainly to check my measurements. But it didn't even come close to the real weight. Here's an extract from my online diary (http://www.lemis.com/grog/diary-jun2008.php#17 : The other thing of interest is the weight of the pot, since it enters into the thermal calculations. One option is to measure the volume and calculate it. For the 100 litre pot I get the following details: Thickness 0.4 cm Outside diameter 53.0 cm Inside diameter 52.2 cm Height 45.3 cm Area base 2206.2 cm2 (outside diameter2 / 4 * pi) Volume base 882.5 cm3 (area * thickness) External volume 99940 cm3 (area * height) Internal volume 96946 cm3 (inside diameter2 / 4 * pi * height) Volume of wall 2994 cm3 (external volume - internal volume) Total volume of pot 3876 cm3 (volume of wall + volume of base) Weight of pot 10465 g (total volume * 2.7, density of aluminium) The problem is, the pot only weighs 5.8 kg, including the handles which I didn't account for here. Take them away and it's reasonable to assume that I have calculated exactly double the real weight. The same applied for the other pot. But how? I can't see anything wrong in my calculations, and though my measurements of diameter and height might be out by a millimetre or two, I measured the thickness with vernier calipers, and they agree with the specifications. Put it to people with time on their hands, the ones on IRC, and they all came up with the same answer within the constraints of rounding. So what's the answer? Hollow pot? Unlikely. Tapering thickness? It would need to taper to 0 to explain this discrepancy, clearly not the answer. Different alloy? It would have to have a density of 1.35 or so, and alloys that light are expensive. The pots weren't. I'm still puzzled. Does anybody have an insight? Greg - -- Finger grog at Freebsd.org for PGP public key. See complete headers for address and phone numbers. Return to table of contents
Date: Wed, 18 Jun 2008 06:57:00 -0500 From: Tim Runnette <trunnette at mac.com> Subject: Re: Sanitizers Thnx for posting the archive link Tom. Great episode. Below is the link to the Five Star Chemical site. It has product info and some other homebrew info. http://www.fivestarchemicals.com/brew.asp Cheers, Timmy Return to table of contents
Date: Wed, 18 Jun 2008 10:32:29 -0400 From: "steve.alexander" <-s at roadrunner.com> Subject: Phenomenology and beer - pt 2 So food/flavor scientists have taken this issue to extremes. I would suggest that anyone interested seek out the writing of "J.R.Piggott" of the University of Strathclyde, Glasgow. I have a copy of his (editor) "Understanding Natural Flavors" and also his "Science and Technology of Whiskies"; both are very difficult to find. Piggott seems to publish in a range of flavor/taste/food journals, but also occasionally in JIB with respect to beer and whisky. I don't have a copy of Piggott's "Sensory Analysis of Foods" which probably has a better and detailed description of the methods. Food scientists often use a panel of expert tasters and it is expected (and tested) that these panels have consistent stimuli/QD mappings. It turns out that we can transform the stimuli/QD mapping of individuals or groups into a normalized form in a very clever way. You give an individual a set of samples and have then produce a weighted "short scale" of terms and values for each (one beer rates 3 on sweetness and 7 on bitterness and 2 on floral aroma and ...) . The terms the user chooses form non-orthogonal axes that can be mathematically transformed to correspond to others terms or more usefully transformed to match the known composition differences of the stimuli. So QDs can be "corrected" or normalized in a sense. Your "oaky" becomes my 0.5 phenolic + 0.4 vanilla + 0.1 harsh. Now when it comes to the hedonic scales (what we actually like/enjoy) "principal component analysis"(PCA) is often used. Here is a short paper on the topic, www.snl.salk.edu/~shlens/pub/notes/pca.pdf and the first few sections give a very readable description. It's based in the Karhunen-Loeve transform, that I first came in contact with in the realm of pattern recognition. The PCA can be thought of as a form of pattern recognition where we normalize the statistics of each dimension, find and reduce the most significant axes in order. There is a linearity assumption that clearly doesn't rigorously apply to taste/flavor/hedonic rankings. So there are ways to overcome the subjectivity hurdle - or at least push it back into the corner. == Back closer to the real world and specifically to mouthfeel/body/viscosity. I tend to personally agree with Dave Harsh that mouthfeel encompasses the non-flavor, non-aroma components, and the "body" or similar more specific term is the topic. It is clearly (IMO), related to viscosity, but there are as Matt Baums suggests other factors at work. I personally do think we want to consider things like the "electronic nose" (Google it) which are attempting to replicate the human olfactory system, but extended to measure other food parameters like "mouthfeel. That doesn't mean it would replace humans in judging, but it could help us understand ourselves better. The whole idea of segregating beers according to style in Kunze (a book with too few references listed) divides the topic into "Palatefulness(body)" and also "Tingle" . Tingle is from CO2, but also impacted by pH (lower pH, more tingle). The body factors are, according to Kunze related to alcohol content and residual extract, but also dark more highly cured malts, high MW proteins (10k-100k daltons) . Kunze specifically states that overmodified malt leads to poor body. And long mash rest 45C-55C leads to low tingle and poor foam. Also ... "addition of gypsum [calcium sulfate] or calcium chloride to the brewing water also increases the sensation of mellowness and body on drinking. Residual alkalinity and acidification produce more full bodied softer beers". My reading between the lines has Kunze pointing to high MW protein and calcium ions along with residual extract(dextrins) & alcohol. My opinion is that protein (type) and carbonation level are extremely important to body. I think we've all had a keg in the fridge over an extended period and early-on the foam and head are huge and the body correspondingly high, but over time protein drops, the beer clears, and at the same carbonation level the head declines along with mouthfeel. Wheat beers, with a notch more protein and high carbonation often have great palatefulness. Hops has a considerable positive impact on foam and some APAs seem to have enormous body in the CO2/foam-like sense of palatefulness. Another example is Guinness which obviously has low residual extract, perhaps higher protein from the roast barley and modest alcohol, but the co2/nitrogen/protein give this beer an enormous initial sense of body. Degassed Guinness OTOH is quite thin and lacking in body. Dextrins are also clearly important; but I get a hedonic negative vibe from excess dextrins as I expect a bloated tummy as a result. Another example for consideration are beers with oats or sometimes rye or other tertiary brewing grains. It seems that the glucans create a silky, almost oily mouthfeel that has a clear "body" impact. Fwiw tests among coffee tasters show that the sensation of body in coffee is almost directly related to the extracted oil content. Of course finished beer has almost no oils. -s Return to table of contents
Date: Wed, 18 Jun 2008 17:30:14 -0400 From: Kai Troester <kai at braukaiser.com> Subject: Fast Ferment Test I have been using the a fast ferment test for a while to determine the limit of attenuation for the beers that I brew and was introduced to this test by German brewing literature (home brewing as well as commercial brewing). While I find it very useful to know the limit of attenuation, especially when brewing lagers or higher gravity beers, I have not heard about it in the American home brewing community. The idea of the fast ferment test is to take a sample of wort and overpitch it with yeast (preferably the yeast that the batch is fermented with). Together with fermenting it warm (70+ F is great) this should result in a complete fermentation of all the sugars that this particular yeast can ferment (there is actually only a small difference in the wort sugars that Ale and lager yeasts can ferment). The resulting attenuation of this fermentation sample is the limit of attenuation of the wort and provides an upper boundary to the attenuation that can be expected from the main fermentation. It only depends on mashing and thus provides a nice separation between the mashing and fermentation contributions to the final beer attenuation. Fermentation characteristics like yeast strain, pitching rate, temperature and so on will determine how close the yeast will get to the limit of attenuation and the residual fermentable sugars become an important part of the character of the beer. A more comprehensive write-up on this test can be found here: http://braukaiser.com/wiki/index.php?title=Fast_Ferment_Test Is this test known among American home brewers and was determined to be unreliable or to much work? Why don't we teach new brewers this test? I would have at least expected it in more technical home brewing literature. While not really useful for a brewer who is happy with the attenuation of his/her beers, it provides very useful information for troubleshooting attenuation of a beer as it will tell you if your problem lies in mashing or in fermentation. Kai (Massachusetts) Return to table of contents
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