HOMEBREW Digest #793 Wed 01 January 1992

Digest #792 Digest #794

		Rob Gardner, Digest Coordinator

  oxygen, mashing &c. (chip upsal)
  Rob Winters' beginner's questions (Norm Pyle)
  Oxidation  of wort  HBD#792 (Dan Kerl)
  Oxidation of hot wort? (KENYON)
  oxygen timing, active starters (Stephen Russell)
  St. Patricks of Texas and sign off (Donald Oconnor)
  starters and lag times (Frank Tutzauer)
  Redox, Redux (Martin A. Lodahl)
  Re: Homebrew Digest #792 (December 31, 1991) (Dave)
  Straining the Wort (Arthur Delano)
  More on Oxidation (C.R. Saikley)
  In Search of Spigotry (Martin Lodahl)

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---------------------------------------------------------------------- Date: 31 Dec 91 08:18:37 EST From: chip upsal <70731.3556 at compuserve.com> Subject: oxygen, mashing &c. Al writes: >'ve wondered about this. Intuatively, I figured that a shower-like >sprayer >would be the best way to evenly distribute the sparge water and minimize >the >disruption of the grain bed, and planned to include such a device in a >lauter >tun I've been planning to build. However, wouldn't spraying the sparge >water >oxygenate it? Wouldn't the resulting oxygenated water create oxygenated >wort, >which at temparatures above 80F, would quickly produce oxidized wort? >Now... what do all of you think about this? I do not beleve there is any problem with oxygenation of sweet wort. The problem comes when hopps come into play. Randy ask: >1) In Line's book, his procedure for a step mash suggests doing the >"protein rest" or first stage at 55C (131F), but Papaizan suggests >50C (122F). Who's right? Does it really matter? >From what I have read here and elsewhere a proteen rest is not nessessarly nessary. I skip it unless I have a lot of adjuncts or malted wheat. Then I hold at around 122F >2) The recipe I'm using from Line's book (for a light pilsner, a >Heinekin clone), he calls for 5.5 lbs of "lager malt". What kind of >malt is this? 2-row or 6-row? Unmodified, modified, or highly >modified? Eurpian lager is generally 2-row while american is 6-row. As far as I understand lager malt is *generally* less modified then ale malt. >3) In Papaizan's book, he says that 2-row barley has a LOWER enzyme >content than 6-row. But in my catalogue for the Home Brewery, they >tell me that 2-row barley has HIGHER enzyme content than 6-row. >Line's book didn't mention it. What's the deal? The two row malt in question in the cattloge is called Kagles. This malt has a lot of enzymes for two row; weather it really has more the 6-row I could not say. Chip Return to table of contents
Date: Tue, 31 Dec 91 08:14:05 MST From: pyle at intellistor.com (Norm Pyle) Subject: Rob Winters' beginner's questions Rob writes: >Why d'yer think my wort didn't make it to the sg that the kit predicted? <Too low a temp or not enough time processing the crystal malt, perhaps? <Do these kits (or specific ingredients) have a shelf life that I should be <concerned with? I think you're on the right track about the crystal; probably not enough time extracting all of its sugar. I wouldn't worry about shelf life, at least as it pertains to OG. >Why did this batch not seem to want to ferment out? Temperature? The air >temp was 72degF, if my heat pump is working. Not enough oxygen at the start? >Should I have ignored the kit instructions and waited for zero acitvity? The temperature is fine; I would suspect a lack of oxygen at the start. I would also have waited a bit longer but I don't think you'll have any bombs at 1.017. Just to be safe you might consider refridgerating the bottles. >Why did my ending sg come out above the kit's prediction? Will too high a >temp processing the crystal malt result in unfermentable sugars? Was it >just plain not done yet? Crystal malt is intended to add unfermentable sugars. This is related to your last question. >I also have questions about storage and shelf life. How should homebrew be >stored? Is the basement floor good enough, or should it be refrigerated? >I still have porter that has been basement floored for about a year. Is it >good, or is it time to wash the bottles for another batch? I didn't see >any mention of these issues in Papazian's book or the kits' directions. Basement temperatures should be sufficient, but then I've never seen a year old homebrew. Mine must be crawling out of the crawl space 'cause they're usually gone in 3-4 months. I certainly wouldn't pitch those porters until I gave them a good tasting. Do you need some help? >There seems to be some debate going on about head space at the >moment. I realize that excessive head space will mean excessive oxygen >which will tend to spoil the brew. Won't insufficient head space result in >broken bottles, because there's nothing to compress as the beer primes? I've been told about a 1-1.5 in. head space is ideal. Too much is supposed to result is under carbonation because there is not enough sugar to fill the space with CO2. I don't know what too little head space would do. Hoppy New Beer!!! Norm P.S. You should make a holiday beer: call it, "Rob Winters' Smith Welcome" :-) Return to table of contents
Date: Tue, 31 Dec 91 10:14:18 CST From: kerl at cmack.b11.ingr.com (Dan Kerl) Subject: Oxidation of wort HBD#792 The key words here are "oxidation" versus "oxygen" Oxidation means that some substance in the wort (usually hop oils) has chemically combined with atomic oxygen in some fashion. This process also occurs when iron rusts, wood burns or cooking oil becomes rancid. This atomic oxygen has a great affinity for electrons that are part of other molecules in the wort. In order for the yeast cells in the wort to reproduce, oxygen must be present (so the yeast cells can 'oxidize' things in the wort as they see fit). Note that this is molecular diatomic oxygen (like the stuff you breathe). Since the oxygen is 'combined with itself', it is not combined chemically with any of the substances in the wort, just dissolved in the wort. Boiling will cause this dissolved gas to leave. Since oxygen must be present for oxidation to occur (discounting other reactive substances in the wort like chlorine), relatively little of it will show up during the actual boil. Since oxygen is so reactive chemically, SOME of this molecular oxygen will 'break apart' to chemically combine with other substances. This process is what we call oxidation. The rate at which most chemical reactions proceed varies exponentially with temperature. This is why it's beneficial to get the wort temperature down as quickly as possible following boiling. Introudcing oxygen to the wort WHILE STILL HOT will greatly increase the levels of oxidized hop oils in the wort. It also means that there will be less molecular oxygen available for the yeast to use for their aerobic reproductive phase. So it appears that a conflict exists. Oxygen needs to be kept away from the wort to stop oxidation of wort components. Oxygen needs to be added to the wort because the yeast cells need it to build up their population. The variable that we have control of in the process is temperature. Adding oxygen to the wort when cold accomplishes two things: 1. It exponentially reduces the chances that a molecule of the oxygen will become involved in an oxidizing reaction in the wort. 2. More molecular oxygen will stay dissolved the wort, allowing the yeast to build up a working population more quickly. The best compomise that anyone appears to have come up with is: a. Keep as much oxygen as possible away from the wort while it is hot. b. Cool the wort as quickly as possible, still keeping oxygen away. c. Add oxygen (aeriate) to the wort only when it reaches pitching temp. d. Pitch yeast as soon after this as possible. e. A yeast starter would probably help, since more active cells would be introduced to the wort. These would scavange the molecular oxygen from the wort more quickly, reducing the number of molecules available to contribute to the oxidation process. Dan Kerl kerl at cmack.b11.ingr.com Return to table of contents
Date: Tue, 31 Dec 1991 13:34 EDT From: KENYON%MOE.ERE-NET.COM at pucc.PRINCETON.EDU Subject: Oxidation of hot wort? Happy New Cheers All, In the last few months there has been much (much) discussion about oxidation. I recall several comments to the effect that aerating the wort by turbulently dumping it into the primary while still hot (ie, just off the boil) will result in oxidized beer , while aerating cold wort will provide oxygen necessary for the yeast to make like andr ogynous bunny rabbits and ......... Anyways, what gives here? As the wort cools, does t he oxygen come out of solution leaving the wort cold, lonely, and tainted? As a Mechanical Engineer ("If you can't see it, it doesn't exist"), I could prob ably be pacified enough to fall asleep tonight if someone just tells me that PV=nRT, pat s me on the head and says "go play in the sandbox, now". Serious though, I do find this a bit puzzling, so if some kind soul could email me a bit more info as to why this is so, I would muchly appreciate it! Merry Holidays -Chuck- Return to table of contents
Date: Tue, 31 Dec 91 15:54:35 EST From: srussell at snoopy.msc.cornell.edu (Stephen Russell) Subject: oxygen timing, active starters Hey gang, Happy New Year's! In HBD #791, mm at lectroid.sw.stratus.com (Michael Mahler) sez: > In Papazzian's New Joys of Homebrewing, he says that you > should oxinate the bijeebers outa the wort so the yeast has plenty > of oxidation to munch on and here y'all are saying that > this is really bad. The question is WHEN is oxidation good. The answer is ONLY after the wort has been cooled and the yeast has just been pitched or is about to be pitched. AT ANY OTHER TIME, it's bad. Hot wort will oxidize readily if you splash it around and will be highly susceptible to staling later. The same with beer during or after fermentation. A stronger-flavored beer will mask the effects of oxidation, as will drinking it before it ages long enough to show the effects of oxidation (the reaction is slow at room temperature or below). and "John Cotterill" <johnc at hprpcd.rose.hp.com> asks about yeast starters.... >About a week and a half ago, I made up a yeast starter from wort and the >contents of a Wyeast liquid yeast package. The fermentation of the starter >finished 2-3 days later. It has now been over 10 days (total from pitching) >and I still have not been able to find the time to start my brew. I doubt >if I will be able to do it before this weekend. How long can starters sit >around? I will put the starter in the refrig. tonight (its been in the kitchen >at about 65 deg F). Should I make a new one for this weekend? The _Zymurgy_ Yeast Special Issue (Vol. 12 No. 4, 1989) has an article that basically directs you to prepare another starter, wait for that one to begin actively fermenting, and *then* pitch into your batch. The point of starters is to add a large amount of *active* yeast. If this starter goes dormant, then make another, etc., etc. It seems to me that you could increase the volume of subsequent starters so as to attain a higher cell count, which would reduce the lag time after pitching. I don't have the issue in front of me, but if my memory serves me correctly, then I remember a series of pictures, one of a frothing Erlenmeyer flask starter with the caption "appropriate for pitching" and one of an inactive starter with the admonition to "make a new starter". By the way, in something of a 'rebuttal' (:-) to those who advocate using your glass carboy for a starter container, I recommend these flasks for the sole reason that they are made of Pyrex [TM] and can be placed directly on your stovetop. You can therefore boil your starter solution right in the vessel it is going to ferment in. Can't get much more sterile than that! Of course, since you have to cool the wort before you add the yeast, be prepared for a lengthy cooldown; Pyrex doesn't transfer heat very well. Yours in the Suds, STEVE =============================================================================== Stephen Russell Graduate Student, Department of Materials Science and Engineering Internet: srussell at snoopy.msc.cornell.edu work: 607-255-4648 Bitnet: srussell at crnlmsc3.bitnet home: 607-273-7306 =============================================================================== Return to table of contents
Date: Tue, 31 Dec 91 12:59:33 PST From: Donald Oconnor <oconnor at chemistry.UCSC.EDU> Subject: St. Patricks of Texas and sign off I received many replies regarding my posting of my wife's homebrew supply in Austin. I'm leaving for Austin in about 30 minutes so here's the info again (I won't have email there.) St. Patrick's of Texas Brewers Supply 12911 Staton Drive Austin, Texas 78725 512-832-9045 I apologize to anyone offended by this ad. My wife had a shop here in Santa Cruz for the past 10 months and I avoided making any reference to it on the HBD. WHOOOPS the zip is 78727. I regard the HBD as a source of information so a simple statement about the location or availability of a shop or supplies is fine regardless of who posts it. I and most everyone else only object to some of the incessant dribble such as we saw from ole' you know who. Anyway, my wife Lynne runs the shop out of our home. We have 3 small boys so the business has been wonderful for her because it permits her to stay home with the kids and do something she enjoys very much. She does do mail order so if you are in that area of the country, just request a catalog. I also received many reponses regarding the Dr. John 'keep this crap to yourself' business. Dr. John was a really good sport and sent an apology once he realized that Lynne O'Connor was my wife. My wife and I took no offense to his first letter because we knew he simply didn't make the connection. The statement "she promised to sleep with me if I posted this" would have been neither appropriate nor humorous if it had not been about my wife. Dr. John was simply the butt of a practical joke and he was good natured about it when he found out. So thanks to everyone who sent a personal note and Happy New Year to all. Return to table of contents
Date: Tue, 31 Dec 1991 16:11 EST From: Frank Tutzauer <COMFRANK at ubvmsb.cc.buffalo.edu> Subject: starters and lag times I'm still a relative beginner (Batch #10 is in the fermenter now), but last night I looked over my notes, and I would like to make a few comments about lag times. The first three batches were made with dry yeast in the summer; all three took off explosively within about 3 hours. Beginning with Batch #4 and Autumn, I switched to Wyeast. I had heard that most people had 12-24 hour lags, so I was careful to always make a starter. Three times I made pint starters, three times the starter was somewhere between 1 and 2 quarts, and once, inspired by Father Barleywine, I pitched onto the dregs of a previous batch. The pint starters were made by boiling a little less than three cups water with 3-4 tablespoons of dried malt extract (DME). After accounting for boil off, I think I ended up with about a pint (U.S.), give or take some. As for the quarts, I first made a pint starter, then boiled some DME with about quart and a half of water. After boil off, I always ended up with something less than a half gallon, but more than a quart. Although there may have been slight variations in temperatures, after pitching I would leave the fermenter at room temperature for a little while, and then move it down to a basement in the mid-60s. Also, the yeast strain was fairly balanced across conditions: American Lager (pint/quart), London Ale (pint/quart), Irish Ale (pint/dregs), and British Ale (quart only). Consequently, I believe that my results are due primarily to starter size, rather than other factors (though other factors obviously had at least some influence). Anyway, the results are as follows: The pint starters all began active fermentation in about a day. Twelve to 18 hours for the lager yeast, and 20 to 24 hours for the two ale yeasts. These numbers are consistent with what others have reported in the HBD. The quart starters, naturally, produced active fermentation in a smaller time span. What was amazing was how much smaller. The naive guess is that with around twice as much starter, you would have half the lag time. Wrong! Exponential growth or something must be going on because in all cases I got a lag of about 3 to 5 hours. The British Ale, which I pitched last night and moved to a 62 degree basement after room temp for one hour, had visible fermentation in under 2 hours and was blowing stuff out of the blow off hose at 2 hours and 45 minutes. What's really amazing is that the one time I pitched onto the dregs, it still took 3 hours for really active fermentation. The upshot is this: If you're worried about long lag times, it really does pay to build up a starter to somewhere between a quarter- and a half-gallon. What's more, going much bigger probably won't make too much of a difference. - --frank  Return to table of contents
Date: Tue, 31 Dec 91 13:16:02 PST From: Martin A. Lodahl <pbmoss!malodah at PacBell.COM> Subject: Redox, Redux In HOMEBREW Digest #792, Michael Mahler asked: > In Papazzian's New Joys of Homebrewing, he says that you > should oxinate the bijeebers outa the wort so the yeast has plenty > of oxidation to munch on and here y'all are saying that > this is really bad. [...] > > So what's the pooop? First let's define terms: Aeration is the dissolution of air into the wort/beer. There is one point in the brewing process where that is desirable to the point of being critical. Oxidation is a chemical change that can be aggravated by aeration. I can't think of any brewing context where it's desirable. Generally it's a good thing to keep the air introduced into the beer to a minimum, except JUST before pitching the yeast. Yeast can operate either aerobically or anaerobically; in their aerobic phase they respire, and reproduce like crazed weasels. In their anaerobic phase they ferment. Giving them the opportunity to "jump start" their colony is one of the best things we can do toward making good beer, PROVIDED the wort is COOL, when aerated!! If it's hot, the class of compounds in the wort called melanoidins are likely to become oxidized, and as they seem to have a role in mediating the oxidation of alcohols to aldehydes, that means trouble (with a capital "T") down the road. Similarly, if you splash the beer around while bottling, that oxygen you've introduced will be available to "help out" with that same reaction, over time. So in short, put plenty of air in the wort just before you pitch, but not at any other time. = Martin A. Lodahl Pacific*Bell Systems Analyst = = malodah at pbmoss.Pacbell.COM Sacramento, CA 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: Tue, 31 Dec 91 15:34:07 CST From: Dave <C05705DA at WUVMD.Wustl.Edu> Subject: Re: Homebrew Digest #792 (December 31, 1991) I am trying to learn how to make a posting. This is an experiment, but suggestions would be appreciated. Return to table of contents
Date: Tue, 31 Dec 91 17:19:27 EST From: Arthur Delano <ajd at itl.itd.umich.edu> Subject: Straining the Wort eisen at kopf.HQ.Ileaf.COM (Carl West) writes: ]Someday I'll get around to making a skimming `paddle' out of some screening ](of nylon or some appropriate metal) that fits the curve of my kettle. After reading that, I was struck with the idea of using an aquarist's net. It's small, square-shaped at one end, with the frame and handle one continuous loop of plastic-coated wire. Easily available in various sizes at pet shops. The nylon mesh is very fine and could probably pull out even dissolved pellet hops. The critical question: would it be safe in a boil? AjD ajd at itl.itd.umich.edu Return to table of contents
Date: Tue, 31 Dec 91 13:19:20 PST From: grumpy!cr at uunet.UU.NET (C.R. Saikley) Subject: More on Oxidation Thomas Manteufel writes : >> Like many other beginning-to-intermediate brewers, I steep my >>crystal malt at 170F for half an hour, and then pour this through a strainer >>into the brew kettle. To which JaH responds : >One of the things that happens during boiling is that it drives off dissolved >oxygen. I don't think that you will get oxidation reactions to a significant >degree from pouring a partial mash through a strainer. Also since this is only >a portion of the wort any effect will be diluted. While it's true that boiling drives off oxygen, Thomas was refering to oxidation occurring after steeping his grains, not boiling his wort. This solution wasn't boiled, and is not free of oxygen. Furthermore, all the splashing and pouring thru a strainer will re-introduce oxygen. I would encourage brewers to avoid splashing hot wort, regardless of whether it is the dense first runnings from an all grain mash, or a weak crystal malt "tea". You may still be OK because of the dilution that Jay mentioned, but on the other hand a grain bag is a pretty small investment to make to avoid splashing. Dr. Lewis at UC Davis tells an interesting tale along these lines. It may not be entirely true, but what the hell, it makes for a good story...... The brew kettles at AB have a pipe running vertically along their insides to deliver Budwort to the bottom of the kettles without splashing. A few years back, one of the large Japanese breweries contracted with AB to brew Bud in Japan. Much to their dismay, they found that Japanese Bud was coming out darker in color (God forbid!) than desired. The beer police in St. Louis astutely asked the Japanese brewers if they had tampered with the afore mentioned wort delivery pipe. It seems that in their relentless pusuit of streamlined production efficiency, the Japanese decided that the pipes made the kettles harder to clean, and promptly removed them. They were instructed to promptly replace them, and the infamous bland consistency was maintained. Hoppy Brew Year, CR Return to table of contents
Date: Tue, 31 Dec 91 22:13:00 PST From: Martin Lodahl <gueuze!mal at PacBell.COM> Subject: In Search of Spigotry My turn to ask one: Up until now, I've been using a lauter tun fashioned from a 29qt plastic wastebasket, a drum tap, a false bottom made from the last 1.5" of a discarded soap pail, and a jellymaker's straining cloth. It's worked just great, with only two small snags: 1) The wastebasket only lasts about a year before developing cracks around where the tap's installed, necessitating replacement, and 2) I can't find that kind of wastebasket any more. Oh well, I'd been thinking about fashioning an insulated tun, anyway. My dear wife gave me an insulated water cooler for Christmas, but I'll be DAMNED if I'll stand there holding that <CENSORED> button in for the whole sparge! Anybody have any ideas where I might find a suitable tap? The drum taps I've always used are just too big for the hole in the cooler, and enlarging that seems a dubious proposition, at best. Suggestions? By the way, this is the "alpha test" at posting directly from my home machine, so if it comes out looking bizarre, you'll at least know why ... - -- pbmoss.pacbell.com!gueuze!mal Martin Lodahl Auburn, CA If it's good for ancient Druids runnin' nekkid through the wuids, Drinking strange fermented fluids, it's good enough for me! Return to table of contents
End of HOMEBREW Digest #793, 01/01/92