HOMEBREW Digest #242 Thu 31 August 1989

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		Rob Gardner, Digest Coordinator

  Re: Homebrew Digest #241 (August 30, 1989) (Steve "Mr. MBA" Lindahl)
  Attenuative Yeasts (Martin A. Lodahl)
  extract efficiency (Pete Soper)

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---------------------------------------------------------------------- Date: Tue, 29 Aug 89 09:23:10 pdt From: Tom Kuhn <hpda!tkuhn at hplabs.HP.COM> OK, for all of you who _hate_ algebra but _can_ plug numbers into a formula (or formulas into a program), here is the relationship between initial specific gravity (SG1) and the temperature at which it was measured (T1), final specific gravity (SG2) and the temperature at which it was measured (T2), and percent alcohol by volume (A), corrected to 60 F. (All temperatures are F.): {0.0190 x (T1 - T2)} + {131.25 x (SG1 - SG2)} = A Based on Papazian, p. 47: (SG1 - SG2) x 105 = % Alcohol by weight (% Alcohol by weight) x 1.25 = % Alcohol by volume and on Doug Roberts (HBD #236) (T x 1.449E-4 - 0.009) + SG(uncorrected) = SG(corrected) Now, how should this be corrected for the additional fermentation which occurs as the result of my priming sugar? (I would prefer not to let some of my precious carbonated elixir go flat so that it's SG can be measured without CO2.) Thanks, Tom Kuhn (Neither a yo-yo maker nor a philosopher of science) tkuhn at hpcuhb Return to table of contents
Date: Wed, 30 Aug 89 8:13:16 MDT From: slindahl at orion.cair.du.edu (Steve "Mr. MBA" Lindahl) Subject: Re: Homebrew Digest #241 (August 30, 1989) Please take me off this mailing this....thank you.... -- ][][][[][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][ slindahl at orion.cair.du.edu slindahl at ducair.BITNET slindahl at duorion.UUCP The Devil finds works for idle circuits to do! ][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][][ Return to table of contents
Date: Wed, 30 Aug 89 9:18:27 PDT From: Martin A. Lodahl <pbmoss!mal at hplabs.HP.COM> Subject: Attenuative Yeasts In HBD 241, Patrick Stirling asks (concerning yeasts): > What's 'attenuative'? Sounds like it's the speed with which > a yeast does its job and goes dormant ... Aha! Had you read Miller instead of Papazian, ... 8-> 8-> "Attenuation" refers to the degree to which wort sugars are used by the yeast. Red Star Ale yeast, for example, munches merrily on simple and duplex sugars, but has little appetite for the more complex sugars. Edme will tackle the triple sugars as well. I've only once tried a semi-controlled experiment where I made two successive batches, varying only the yeast (first Red Star, then Edme). I say "semi-controlled", because temperature during fermentation and fining was essentially uncontrolled, and though the weather was essentially the same (hotter than the hubs of Hell) for both batches, there may have been a significant variable introduced there. The Edme yeast (considered more attenuative by Miller) produced a much drier brew (too dry, in fact, for my tastes), but with fewer initial flaws. Both resolved well, the Red Star batch in about 5 weeks and the Edme batch in about 3, with the Red Star batch always sweeter, fruitier, and with more of the famous banana esters. The sweetness, in particular, I attribute to the difference in attenuation between the two yeasts. > On another tack, what do you think of using ice to cool wort? I've had only good luck with this method, but I'm still at partial-mash brewer. When I've got my BIG kettle so I can boil the whole volume of wort (anyone know a good source for 33-quart enameled steel canning kettles? Can't seem to find one here), I won't have ice-dilution as an option any more, alas. = Martin A. Lodahl Pac*Bell Minicomputer Operations Support Staff = = pacbell!pbmoss!mal -or- mal at pbmoss.Pacbell.COM 916.972.4821 = = If it's good for ancient Druids, runnin' nekkid through the wuids, = = Drinkin' strange fermented fluids, it's good enough for me! 8-) = Return to table of contents
Date: Wed, 30 Aug 89 12:39:25 EDT From: Pete Soper <soper at maxzilla.encore.com> Subject: extract efficiency "Brian CapouchfEHFTmQ:8:8" <brianc at zeta.saintjoe.EDU> says in HBD 241: >I have a topic of my own: extraction rates on mashed beers. I can't seem to >ever hit the gravity reading that the writers of books recommend. I'm always >lower, and I know it's probably because I'm not doing a good job on my mash >out. Do others also find this common? I do, although I don't know what the mash out has to do with this. One time when making a dry stout I got 31.5 points per pound of Briess 6 row malt. Every other time, using this 6 row, 2 row Klages (Briess), and 2 row British pale (unknown brand) I've averaged 24-29 points per pound with 28 being the average. I've traced the source of some of the discrepancy in my case. I use a "bucket in a bucket" lauter tun with a tap that his fairly high up from the bottom of the outer bucket. This means that when I'm done sparging there are about 3 pints of high gravity wort left below the tap (which I don't use, since it is full of husks). Another factor is that even after I've created all the wort I can boil down to a target volume in a reasonable time, the runnings from the lauter tun have a SG of 1.010-1.1015. The popular literature suggests sparging until the runnings are 1.008 or less (or the pH rises to 6 or above, etc). So I'm leaving extract behind in the grain too but on the other hand, at 1.010 it takes a lot of water to get a little bit of extract :-) Also, I recirculate my first runnings once the wort is running clear. I suspect some of this doesn't make it all the way back through the filter bed. Finally, the above case where I got a reasonably high degree of extract I also had a lower than usual pH. Usually my mash pH is around 5.6 at the start of sparging and this is of course higher than optimimum. > Do they then augment their worts with >extracts to get to recommended gravity levels, or just smile and not worry? I've kept track of my average actual extract and use this to scale the grain amounts to compensate and match gravities. Note that this can go both ways. Some of the winning recipes in "Zymurgy" reflect INCREDIBLY LOW extract. I was looking at one recently that used over 15 pounds of grain to get 5.5 gallons with a gravity of 1.050! if I just copied this I'd get a beer with an OG of around 1.076. It would be too dark, too sweet, underhopped and generally rubbish compared to what was intended. Going in the more usual direction, if the recipe writer gets 1.035 per pound per gallon and you get 1.028, just copying his recipe is going to give you something thin, too pale and overhopped - not something that would allow me to smile very much. Note that I'm reporting my situation to give another data point, not to describe problems in search of solutions. I especially don't want to hear anything more about adding teaspoons of gypsum to one's mash, OK? :-) Incidently, for stove top mashing I've found that a sleeping bag makes a great insulator for maintaining rest temps. I just put the covered pot on a piece of cork in the bottom of the bag (on the floor), then wrap the bag around and over the pot. Protein rests are kept to within a degree of optimum for 30 minutes, while sugar rests lose only a couple degrees per hour. This is with a bag rated at 30 degrees. Return to table of contents
Pete Soper +1 919 481 3730 arpa: soper at encore.com uucp: {bu-cs,decvax,gould}!encore!soper Encore Computer Corp, 901 Kildaire Farm Rd, bldg D, Cary, NC 27511 USA Return to table of contents
End of HOMEBREW Digest #242, 08/31/89 ************************************* -------
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