HOMEBREW Digest #5054 Sun 10 September 2006

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  Beer's Law ("Peter A. Ensminger")
  Re:  Fermenting on trub: hot and cold break ("Ken Anderson")
  Hop Plants too Old? ("Dave and Joan King")
  re: maturation, heat sanitizing, and wheat beer yeast settling ("steve.alexander")
  enzymes/hops degradation. ("steve.alexander")
  Peter E's Questions ("A.J deLange")

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---------------------------------------------------------------------- Date: Sat, 09 Sep 2006 01:49:15 -0400 From: "Peter A. Ensminger" <ensmingr at twcny.rr.com> Subject: Beer's Law Much interesting discussion of Beer's Law in HBD #5052 ... Q1) Is this discussion relevant to the color observed by the ordinary beer drinker? A1) Not entirely. We are talking about spectrophotometric measurements of beer that has been filtered and degassed. Filtering and degassing eliminates light scatter. Light scatter causes a liquid to "disobey" Beer's Law. Certainly, Beer's Law does not apply to a freshly poured Hefeweizen, which is highly carbonated and has lots of suspended yeast. Q2) Why might filtered and degassed beer "disobey" Beer's Law? A2) Aside from "instrument error" and scattering, there might be several reasons: fluorescence or phosphorescence (presumably insignificant in beer); concentration-dependent changes in electrostatic interactions of pigments (phenolics, Maillard products, etc); concentration-dependent changes in the chemical equilibrium of pigments; and maybe some other reasons ... Q3) In beer, is there evidence for concentration-dependent changes in electrostatic interactions or the chemical equilibrium of pigments that might cause it to "disobey" Beer's Law? A3) I am not aware of any. Is anyone else? In my former life as a photobiololgist, I had lots of experience measuring plant pigments (anthocyanins, flavonoids, chlorophylls, carotenoids, etc). We always worried about possible scattering and fluorescence/phosphorescence. But I do not recall reading about or encountering concentration-dependent changes in electrostatic interactions or in the chemical equilibrium of these pigments that would cause our measurements to "disobey" Beer's Law. Given all this, in addition to AJ's Guiness and Oktoberfest data and John V's Beamish data, I think the burden falls upon those who claim that filtered and degassed beer "disobeys" Beer's Law. I have no great desire to get a cuvette that is several feet thick, just so I can test Beer's Law for a Bud Light. Cheers! Peter A. Ensminger Syracuse, NY Apparent Rennerian: [394, 79.9] Return to table of contents
Date: Sat, 9 Sep 2006 09:14:43 -0400 From: "Ken Anderson" <kapna at adelphia.net> Subject: Re: Fermenting on trub: hot and cold break Date: Tue, 29 Aug 2006 09:34:23 -0600 From: "Mike Racette" <mike.racette at hydro-gardens.com> Subject: Mike, you posted this on Aug 29th: <<<Steve A. posted the following the other day in response to the staling thread and I wanted to discuss this more: "The break & trub contain oils that can be readily oxidized and can produce bad flavor by-products. The trub is nice for yeast growth, but you want to separate it out early (secondary fermenter) - while the yeast are still active." I've never noticed a difference if I rack off of cold break when yeast are still active or not, but have always used an immersion chiller and left most cold break behind. Now that I have finally converted an old keg that I've had sitting around for years to a boil kettle and bought a plate chiller I will be sending all cold break to fermenter as many people do. I have always heard that hot break is something you definitely don't want beneath your beer and so have never experimented with it. However, there has been quite a bit of discussion elsewhere from experienced brewers that ferment in boil kettle leaving fermenting beer on top of both hot and cold break (not sure how long until secondary) with no reported ill effects. Just wanting to hear the opinions (both scientific references and experiential results) on this subject, esp. exactly what are the "bad flavor by-products" of both cold and hot break? Mike>>> I've been watching the HBD for responses, but have seen none. Bummer! I, for one, ferment in the boil kettle, on the trub (trub being ALL the stuff). I have never read his account, but I have heard that Jeff Renner has been doing this for years. Please forgive me if I'm mistaken on that. In any event, I'm very happy with the results and the simplicity of this method. Other tasters and I detect no off flavors, aromas, nor do I have clarity issues. Of course the nay-saying status quo crowd will chime in with esoteric claims that it may be good, but it could be better (by using a conventional fermenter). I say bah! I'm able to seal my BK, so I simply cool, pitch, aerate, put the lid on and away it goes. No messing around with sanitizing because the boil does that. Let me add I always use pellet hops, and they seem to be more easily contained. They virtually disappear in the resulting yeast cake. Anyone else doing this successfully? I'd also like to hear more accounts. Ken Anderson Return to table of contents
Date: Sat, 9 Sep 2006 11:57:42 -0400 From: "Dave and Joan King" <dking3 at stny.rr.com> Subject: Hop Plants too Old? I've been growing hops for about 10 years now, supposedly Cascades and Fuggles, which is probably right. Is there a life cycle, such that they don't do well after so many years? Mine did OK this year, about 40 oz. harvested (dried), with probably that much wasted, I just didn't get them picked and dried. The volume is OK, but the hop cone size was generally small. We seemed to have a great year, hot and wet here in South Central NY (Endicott, near Binghamton). The Japanese beetles were really bad, which ate a lot of leaves, maybe that was the problem. Thanks, Dave King, President of BIER http://www.thebierclub.com/ [396.1, 89.1] Apparent Rennerian Return to table of contents
Date: Sat, 09 Sep 2006 14:17:25 -0400 From: "steve.alexander" <-s at adelphia.net> Subject: re: maturation, heat sanitizing, and wheat beer yeast settling Matt asks ..., << 1. Do higher alcohols ever "age out" of a beer? Some folks take it for granted that fusels will eventually age out, and some (like me) take it for granted that they won't. Anyone have something substantial to back either position up? >> No - there are microscopic losses & additions of common fusels by several mechanisms in stored beer, but the levels will be unchanged for decades if not centuries. << 2. What about volatile phenols, such as the famous "clove" flavor in german hefeweizen? My guess: they don't age out. I base this guess on nothing, except that they are similar in structure to higher alcohols. >> 4VG - the weizen clove flavor - is unstable and has a half-life measured in months in stored beer. It's somewhere far back in the archives but I posted a figure I ran across once - like 4 months at fridge temps, but that's a guesstimate. << 3. If an object is put in contact with boiling water, how long does it really take before that object is "sterile" in the sense that nothing remaining is a threat to beer? 1 second? 15 minutes? I think I heard that 10 minutes is necessary to kill thermophilic bacteria, but I have no reference for that. >> There are claims that some spores can survive boiling, so perhaps forever. I'd bet on the 15 minute figure. Steam is reportedly more effective than boiling and probably requires far less time. One must wonder if the microwave is effective too. << 4. Does chill haze or protien haze interfere with flocculation/settling of yeast? If I brew beer with a good bit of wheat in it, will the yeast settle faster at 70 degrees (where much of the haze material is dissolved) or at 40 degrees (where the yeast are more apt to flocculate and settle, but there are now many more little haze particles in suspension getting in the way of the yeast)? >> There are at least 4 recognized genetic mechanisms for yeast flocculation, and almost certainly other unrecognized mechanism, so there is no certain answer, BUT there is no reason to think that protein haze impacts the two major mechanisms common to brewing yeast flocculation. Now chilling a beer in late fermentation may cause yeast to flocculate rather than bubble along at a very slow rate, BUT yeast and other particles will settle more slowly in colder beer. Flocculation is a yeast genetic expression; that is some environmental factor like the lack of sufficient sugars or perhaps a poor energy balance causes yeast cells to express genes that change the cell surface to produce thready-sticky lectin-like surface proteins or to expose surface materials capable of being weakly attached to di-valent ions like calcium and then ... the yeast cells clump together and drop out. The "reason" for flocculation is still open for debate; it's a clear advantage to the brewer or winemaker, but what do the yeast get out of it ? So back to the practical - no I wouldn't expect wheat haze to significantly impact flocculation. But you shouldn't normally need to resort to chilling to knock out your yeast. Fermentations which flocc' poorly are typically a sign of poor yeast health. If you underpitch or underoxygenate or if the gravity is high compared to the amount of yeast pitched or if the wort nutrients are low - then late in fermentation the yeast have sugars remaining to ferment, but they lack the conditions to reproduce - so a very slow plodding fermentation and poor flocculation follow. If your yeast run out of sugars while growth is still possible, then they'll typically drop cleanly and fastest at the higher temp. If your late fermentation is slowed by lack of growth conditions, then chilling may stop the ferment and cause flocculation, but the settling-out will be slightly slower. -S Return to table of contents
Date: Sat, 09 Sep 2006 14:34:34 -0400 From: "steve.alexander" <-s at adelphia.net> Subject: enzymes/hops degradation. From: "Jason Gross" notes > Subject: 100% black patent grist > > I've never wanted to try a 100% black patent grist, but it looks as though > we may soon be able to. Some of my colleagues are developing barley with > heat tolerant enzymes that will survive malting and kilning. > > http://www.ars.usda.gov/is/AR/archive/sep06/barley0906.htm > Ahhh - Cynthia Henson at work again. Her names shows up in the archives for other barley enzyme work. This looks like a more stable alpha-glucosidase, stable thru normal kilning, while beta-amylase quantity and kiln survival rate is the critical saccharification factor for 'normal' beer. With extra alpha-gluc' it would be possible to produce a very highly attenuative wort - as for whisk[e]y or low-carb beer. I've come to realize that beer inherently has a lot of dextrins, and that the body and mouthfeel of beer is dependent on these dextrins. I don't think we'd want to brew conventional beers with this barley. Greg Brewer says, > Subject: Hops degradation > [...] > My guess was to take 10% off the pellets, and 20% off the > whole; any thoughts? > That's the right ballpark. Although the amount of humulones degraded is often much higher than this, the breakdown products still provide bitterness to the finished beer - or so says the literature. -S Return to table of contents
Date: Sat, 09 Sep 2006 19:41:15 +0000 From: "A.J deLange" <ajdel at cox.net> Subject: Peter E's Questions RE Q1: Note that the ASBC method for color determination requires that a second absorbtion measurement be taken at 700 nm where beer absorbs little light. If this measurement isn't less than 0.039 times the measurement at 430 nm the beer is deemed turbid and must be centrifuged or filtered. RE Q2: Consider that a liter measures E9 x E9 x E9 Angstroms on a side i.e. has a volume of E27 A^3. If we put 1.6 millimole (E21 particles) of some substance into a liter of water that's 1 particle per million cubic Angstroms i.e. each box 100 Angstroms on a side contains on average 1 particle. The average molecule is probaly 10 A or less in size but some polymerized things might reach 100 A in length. The wavelength of 430 nm light is 4300A. Makes you wonder. But consider a beer with absorbance 1 in 1 CM (12.5 SRM). A photon would have a 10% chance of making it through a path consisting of E7 of these little boxes with a molecule each (1 cm path) and the probability that a photon is captured by a particular molecule is 9E-8 i.e. very, very small. So while the molecules are not that far apart in a 1.6 mM solution and while the wavelength of the light spans quite a few molecules the interraction beetween photons and molecules is apparently very rare, and thus would occur at sites many molecules removed from one another. This, one would think, would imply in independence and hence support for Beer's law. One thing that might cause a change in color with dilution would be if the beer were acid but weakly buffered so that the dilution caused a shift in pH. Lots of things in nature have colors which depend on the redox state of the "dyes" which in turn depends on the pH. But we're not seeing this either. Also a quickie experiment this afternoon showed that adding .1 ml of approximately 13N HCl to 3 ml of beer caused an SRM shift from 17.6 to 16.0 (note that adding .1 mL of water would scale SRM to 17.0) so pH change, while it does have an effect, doesn't seem to have a very large one. A.J. Return to table of contents
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