HOMEBREW Digest #4908 Fri 09 December 2005

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  Fermentation tracking ("Fredrik")
  $600 Tables etc. ("A.J deLange")
  RE: Cake-taking record anal CO2 tracking (Jeffrey Byers)
  CO2 flow meter (ALAN K MEEKER)
  re:decoction vs infusion (Nathaniel Lansing)
  RE: A couple of questions/remarks regarding #4905 & #4906 ("Mike Sharp")
  -S (zuvaruvi)

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---------------------------------------------------------------------- Date: Fri, 9 Dec 2005 08:08:33 +0100 From: "Fredrik" <carlsbergerensis at hotmail.com> Subject: Fermentation tracking The measurement discussion is reaching an end now and Ken posted some of his nice flow meter data. I'll just add again my support for the gas flow measurement ideas that has been discussed before and I haven't changed my mind, because I've already learnt things from it, so it works for me, growing confidence intervals aside. My opinion is that while we should *of course* always strive to improve accuracy and certainty in measurements, we must not be fooled and rejected by noise! Sometimes what we blaim on "noise" is nothing but a mirror of our own ignorance. I always try hard to never confuse unlikely or diffucult, with impossible, because they are fundamentally different. Once you *think* something is impossible, when it might just be darn tricky, you aren't even trying! and your world is instantly smaller. Just look at life, it's amazing. But is it probable? What do I know. I do not have as nice flow meter as Ken, but I've toyed around with counting bubbles, and even such admittedly less accurate method is very useful. But you need averages, not single counts of course. Also you kow the end points anyway, since I typically measure OG and FG anyway as a doublecheck. That's good enough for a starter. I had my computer count the bubbles for me. I made two working prototypes, one trigging on the sound(microphone in airlock), one using a optical fotosensor & emitter in airlock neck. But since then I haven't worked more on it. I've acquired the first basic info I needed for a test. The next task in order to make sense out of the profile is the modelling, that's where I am atm. Once that's done I'll probably revise the measurement process. The fermentation profile contains alot of information about yeast growth and the nutritional status of the wort, which in turn may have significant impact on flavour formation. You don't get near these things from single OG, FG readings except if you note the total fermentation time. But the information doesn't present itself in english letters, you have to *pull* it out yourself by means of your imagination/creation. I have also done some pre-tests with measuring the heat of the culture, using one probe in the fermenting culture and one outside. The Differential temperatur again nicely mapped out the typical activity profile (acceleration, peak, deacceleration) as is expected by theory. I used cheap temperature transducers wich are not overly accurate, but they are fairly precise. Add on top of that, that noise reduction, and calibration if you want, and you can get pretty good numbers, for little money. Sure you can go an buy PRO gear which are great and easy to use, but it easily gets out of budget for a homebrewer. Does that mean we are stuck? I don't think so, only if we think so. Our imagination and creativity is the biggest bottleneck. Consider how this world started, we should not fear noise and darkness :) I think that we sould not be blinded by incompleteness and noise, my strategy is to compare all the data I get possibly get, with theory. In this way I trust theory to also help me tell what's significant and what's not. I believe in a certain degree of self rectification as inconsistencies are short lived. To a certain extent this happens also in the observers mind, not only in the measurement instrument. I think the gas analysis (by various means), temperature analysis, and maybe head pressure analysis are all methods well wort exploring. And it doesn't *have to* take a million dollars of lab equipment. Of course it would make like easier, but that's another story. We have to play the cards give to us. /Fredrik Return to table of contents
Date: Fri, 09 Dec 2005 13:13:51 +0000 From: "A.J deLange" <ajdel at cox.net> Subject: $600 Tables etc. $600 Tables: The ASBC is the American Society of Brewing Chemists. It is, among other things, the publisher of a set of "Methods of Analysis", a set of protocols for measuring properties of malt, wort, beer, hops adjuncts etc. The MOAs come in a hefty three ring binder or on a CD and the cost is nearly, if not quite, $600. Several of the methods contain or refer to tabulated data which is found in the Appendices. An example is the set of hydrometer corrections Steve and I have been referring to. Others are strengths (Plato) of wort at various specific gravities (Plato tables), specific gravities of alcohol solutions and the statistical tables necessary to carry out the triangle test Steve referred to in his post today. A subset of the MOAs i.e. those which are most likely to be used by craft brewers is also available for substantially less than $600. My comment "save your $600" referred to the fact that much of the tabular data is easily expressed in terms of a polynomial. Strength of wort, for example, can be calculated from specific gravity by P = (((136.10405*S - 630.60634)*S + 1111.48785)*S - 616.98918 where S is specific gravity. Note that this is not the "official" ASBC polynomial but the result of my own fit to the data which I am posting here out of respect for the copyright laws and because it is a better fit (though not to the extent that it makes any real difference). I also have polynomials for alcohol solutions and water and little Excel spread sheet that calculates the triangle test probabilities. I posted polynomials for the hydrometer corrections the other day. Anyone who wants any of this stuff should just drop me an e-mail. Decoction: I think the beers I decoct are delicious. If that is because of something other than decoction please don't shatter my fantasy that it is. GAC: Stands for Granulated Activated Carbon. Wonderful stuff in that it has a huge effective surface area per unit weight and the activated sites will adsorb and/or react with a wide assortment of things like chlorine and chloramine in brewing and Sarin and Tabun in a soldier's gas mask and chemical suit. Density: The formal definition is the mass per unit volume so if whatever you are interested in is contained in the volume you define it will effect the density. Fish in a swimming pool will effect the density of the water in the pool if the volume contains the entire pool. They will not if the volume is defined as a 1 cc sample drawn from the surface. Whether or not something in suspension is detected by a measurement depends on the measurement technique. A hydrometer reading depends on whether the hydrometer displaces the suspended objects which clearly isn't the case with fish or tires thrown into the pool (besides which the fish adjusts his swim bladder to maintain neutral boyancy so his density is that of water) but it would displace yeast cells. In an oscillating U-tube meter or pycnometer what gets measured is the total mass in the sample tube (which is of fixed volume). If fish or tires got in there they would influence the reading (except for the fact that the fish is of neutral buoyancy). CO2 Tracking: That's pretty cool. Return to table of contents
Date: Fri, 09 Dec 2005 07:39:20 -0600 From: Jeffrey Byers <jbyers at yakfarm.net> Subject: RE: Cake-taking record anal CO2 tracking Very cool. two questions. Do you monitor the CO2 outgas rate periodically and assume rate is linear between measurements to perform the total CO2 calculation or do you monitor continuously? Is the output from the flow meter electronic or mechanical? I am thinking of using a PIC microcontroller (cheap under $10) to do the same thing and send the information (flow rate vs time) directly to my computer. Need to buy or build (and calibrate) a meter the PIC can read. regards, jefe Return to table of contents
Date: Fri, 09 Dec 2005 08:45:04 -0500 From: ALAN K MEEKER <ameeker at mail.jhmi.edu> Subject: CO2 flow meter Ken Anderson gave a link to data from his CO2 flow meter, Nice graph! Would like to see the SG plot expanded. Was this the calculated SG form the CO2 measurement or was the SG independently measured? How much was the meter? Based on your numbers it looks like your fermentation gave off about 5.5 pounds of CO2 which sounds about right for a 10+ gallon batch and considering that only about 1/3 of the sugar mass could get converted to CO2. ========================================== Alan Meeker, PhD Assistant Professor of Pathology Department of Pathology Division of Genitourinary Pathology Bunting-Blaustein Cancer Research Building Room 153 1650 Orleans Street Baltimore, MD 21231-1000 Return to table of contents
Date: Fri, 9 Dec 2005 09:37:26 -0500 From: Nathaniel Lansing <delbrew at compuserve.com> Subject: re:decoction vs infusion In the BT article decoction vs infusion there were some problems with attenuations and lag times. I'd hardly draw on that experiment with disorderly fermentations as the definitive answer. Perhaps the yeast selection is the determining factor that accentuates the maltiness precursors formed in the decoction mash. If I remember correctly the yeast used was 2206, not a particularly malty yeast to start with. With orderly fermentations another yeast could very well have indicated the differences. That experiment had as many error factors as a hydrometer, and I doubt it could be repeated; my hydrometer at least has some repeatablity. >From JIB vol 108:1 (2002)"Although not investigated in the current work different yeast strains produce different amounts of furanones from the same worts2,13. Therefore it would seem feasible that suitable choice of yeast strain could be used to increase or decrease beer furanones from the same worts." Return to table of contents
Date: Fri, 9 Dec 2005 10:19:49 -0800 From: "Mike Sharp" <rdcpro at hotmail.com> Subject: RE: A couple of questions/remarks regarding #4905 & #4906 Bill Velek asks: What is "GAC filtration"? I'm guessing that it might be Ground Activated Carbon or something like that. Close. It's Granular Activated Carbon. Most home filter are composed of small grains of activated carbon. loosely packed. IMO, the finer the grain, the better. As someone pointed out, a monolithic block is best, but you don't see those very often, and they require higher pressure. In fact, I'm not completely certain I've ever seen it used for water filtration, though it's fairly common for air filtration. I believe monolithic AC filters do support a higher flow rate than a granular bed of AC. This isn't because the carbon is better, but it's due to the kinetics of the flow of the fluid, and the fact that the effective surface area is much higher (which seems counter-intuitive). As an interesting side point, the activated carbon that is used to fill the vacuum space of a thermos flask (dewar) is actually made from coconut shells. These produce an extremely high quality form of AC (very small pores) which is better at adsorbing hydrogen. Hydrogen is generally the gas that leaks in and ruins your vacuum bottle. Activated carbon, when it's used to adsorb gas like this, is called a "getter". Regards, Mike Sharp Kent, WA [1891.3, 294deg] AR Return to table of contents
Date: Fri, 9 Dec 2005 13:23:56 -0500 From: <zuvaruvi at cox.net> Subject: -S >Steve Alexander, thanks for setting me straight on >specific gravity and >buoyancy; your explanation regarding the fish rising when >a boat is >launched makes perfect sense to me. That's what I love >about this hobby >and this group: I'm always learning stuff. As for your >comment about >monitoring gravity during the fermentation, whatever >floats your boat; >but.... Don't encourage him, he's already got a fat enough head.... XXOO, Chad Return to table of contents
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