HOMEBREW Digest #3032 Mon 17 May 1999

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		Digest Janitor: janitor@hbd.org
		Many thanks to the Observer & Eccentric Newspapers of 
		Livonia, Michigan for sponsoring the Homebrew Digest.
				URL: http://www.oeonline.com

  RE: magnetic stirrers (LaBorde, Ronald)
  Champagne caps/AHA Nationals (Kim Thomson)
  O2 caps some more... ("Nathaniel P. Lansing")
  Reviving lost starters(Bob Fesmire) (DGofus)
  Trouble with the kraeusen that won't go away ("Phil & Jill Yates")
  stir plate (John_E_Schnupp)
  catales (JPullum127)
  Wyeast 3068 ("Fred L. Johnson")
  Yeast culture in stirring flask ("Fred L. Johnson")
  More eastern sounds that are beer related, and probably nobody cares about. ("Dr. Pivo")
  Primetab (Bobpreed)
  Titratable Acidity/Phosphate (AJ)
  Is it just me....or (Joe Rolfe)
  diacetyl mouthfeel (AJ)
  Label Fixing (Brad McMahon)
  Ruddles Best Bitter and Stone's Best Bitter. ("Roy E. Dawson")
  Yellowing leaves (ThomasM923)
  Re: Yeast culture in stirring flask (Domenick Venezia)
  Re: quick weiss question ("George De Piro")
  Medicine Rock Keg (JYANDERS)
  2000 AHA Home Brewers' Conference (Some Guy)
  bacteria (JohanNico)" <JohanNico.Aikema at akzonobel.com>

Beer is our obsession and we're late for therapy! 2000 MCAB Qualifiers: Spirit of Free Beer! Competition 5/22/99 (http://burp.org/SoFB99); Oregon Homebrew Festival 5/22/99 (http://www.mtsw.com/hotv/fest.html); Buzz-Off! Competition 6/26/99 (http://www.voicenet.com/~rpmattie/buzzoff) Send articles for __publication_only__ to post@hbd.org If your e-mail account is being deleted, please unsubscribe first!! To SUBSCRIBE or UNSUBSCRIBE send an e-mail message with the word "subscribe" or "unsubscribe" to request@hbd.org. **SUBSCRIBE AND UNSUBSCRIBE REQUESTS MUST BE SENT FROM THE E-MAIL ACCOUNT YOU WISH TO HAVE SUBSCRIBED OR UNSUBSCRIBED!!!** IF YOU HAVE SPAM-PROOFED your e-mail address, the autoresponder and the SUBSCRIBE/UNSUBSCRIBE commands will fail! Contact brewery at hbd.org for information regarding the "Cat's Meow" Back issues are available via: HTML from... http://hbd.org Anonymous ftp from... ftp://hbd.org/pub/hbd/digests ftp://ftp.stanford.edu/pub/clubs/homebrew/beer AFS users can find it under... /afs/ir.stanford.edu/ftp/pub/clubs/homebrew/beer COPYRIGHT for the Digest as a collection is currently held by hbd.org (Pat Babcock and Karl Lutzen). Digests in their entirity CANNOT be reprinted/reproduced without this entire header section unless EXPRESS written permission has been obtained from hbd.org. Digests CANNOT be reprinted or reproduced in any format for redistribution unless said redistribution is at absolutely NO COST to the consumer. COPYRIGHT for individual posts within each Digest is held by the author. Articles cannot be extracted from the Digest and reprinted/reproduced without the EXPRESS written permission of the author. The author and HBD must be attributed as author and source in any such reprint/reproduction. (Note: QUOTING of items originally appearing in the Digest in a subsequent Digest is exempt from the above. Home brew clubs NOT associated with organizations having a commercial interest in beer or brewing may republish articles in their newsletters and/or websites provided that the author and HBD are attributed. ASKING first is still a great courtesy...) JANITORS on duty: Pat Babcock and Karl Lutzen (janitor@hbd.org)
---------------------------------------------------------------------- Date: Fri, 14 May 1999 15:34:00 -0500 From: rlabor at lsumc.edu (LaBorde, Ronald) Subject: RE: magnetic stirrers >From: Randy Ricchi <rricchi at ccisd.k12.mi.us> >I've been thinking of getting a magnetic stir plate and was wondering what >length/shape stir bar I should get. Would 1" be okay? There are X shaped >ones and straight ones. Any advantage of one over the other? Also, what >speed should they be operated at? They seem to have variable speed from 100 >to 1000 rpm's. Get one for sure, you will be well pleased with the results. I was lucky enough to have an old one given to me cuz it wasn't working. A little liquid wrench on the bearing, then some oil and sandpaper (to get the corrosion off of everything), and I had a stirrer. Naturally, I opened it up because I just had to get a peek at the magnet. In fact, that is how I got it in the first place. I was asking my lab friend what the magnet looked like, and he said "Take this old one apart and get the magnet". I can tell you it would be real easy to make one. This is a rather small one with a magnet about the size and shape of a pencil piece about two inches long. It is mounted onto a flat round disk with a cable clamp. This in turn is mounted onto the most chickenshit small and feeble motor I have ever seen. Point is - the motor gets loaded down and almost stalls when you get a good thick yeast slurry going, so I am considering building one with a much better motor and a somewhat larger magnet that will be up to the task. I plan to put some distance or insulation between the motor and the top plate to prevent heating up the flask too much. As far as the magnet that goes inside the flask, you can purchase these very cheaply, $3, $4, or so, and they are teflon coated and sealed. They are anailable in many sizes, I have been using one 1/4 by 2 inches round bar shaped. You could not build one as good without a lot of trouble. I really would like to build a huge monger to put my carboy on top of and slowly stir the fermenter (bye bye to CO2 poisoning), and see what happens. As far as speed, the one I have uses a resistive potentiometer to vary the motor speed. It works, but there is no way to measure speed. One could use the speed control and motor from a drill and have power and variable speed. It's fun to crank the speed up, talk about foam city, you can aerate easily with high speed, I think a speed control would be nice. I slow mine down after a few hours of aeration, then stir fairly well for one day, then feed again and repeat. I say, build it; be a real homebrewer! Ron Ronald La Borde - Metairie, Louisiana - rlabor at lsumc.edu Return to table of contents
Date: Fri, 14 May 1999 12:36:18 -0500 From: Kim Thomson <alabrew at mindspring.com> Subject: Champagne caps/AHA Nationals 1. Zemo askes about caps for european champagne bottles. Homebrew Shops supplied by Crosby and Baker can order 29 mm caps that might fit and some handcappers have reversable jaws that will fit the champagne bottles. 2. Has anyone received their results from the AHA first round in Kansas City? A few of us here sent in entries and haven't received a reply. Must not have been the winning beers they were in our comp.? - -- Kim Thomson Birmingham, AL Return to table of contents
Date: Fri, 14 May 1999 22:37:18 -0400 From: "Nathaniel P. Lansing" <delbrew at compuserve.com> Subject: O2 caps some more... Joe Rolfe says in #3030, "...and I doubt the o2 cap is going to pull that much air out. " The spec from one manufacturer is 2 mL. If you left 10 mL of atmosphere in the headspace they figure this is just about the volume of oxygen you need to remove. FWIW Return to table of contents
Date: Sat, 15 May 1999 07:01:57 EDT From: DGofus at aol.com Subject: Reviving lost starters(Bob Fesmire) I have two starters that i have abondoned. They both have been stepped up once. The one has been in the fridge about 1 1/2 months the other has been at room temps for about three weeks. Are they still good? My brewing schedule has been shot to hell. Where has the last 3 months gone? I thought about adding thier contents to some boiled and cooled malt and seeing if i can get any activity. I was afraid of Autolysis, but I do not think that it is a major factor here. Any help would be appreciated. Thanks. Bob Fesmire Madman Brewery ( somewhat defunct, but trying to get back into it.) Pottstown, PA Dgofus at aol.com Return to table of contents
Date: Sat, 15 May 1999 21:28:20 +1000 From: "Phil & Jill Yates" <yates at flexgate.infoflex.com.au> Subject: Trouble with the kraeusen that won't go away I am going to try and be a little more circumspect with what I have to say. I don't want to upset the classroom any more than I already have and I certainly don't want to be frog marched out the door by " the bouncer "! Hey, I like it here. Dave and I have resolved the matter between us so it is now something of a dead issue, at least as far as we are concerned. On the matter of wheat beers, I have just produced two using White Labs WLP 300 Hefeweizen yeast and I must say the fermentation performance was something to behold. I have never seen a kraeusen that just kept going like this one. Out the top it came and marched around the brewhouse looking for something else to eat! On the second one I dropped the temp. back to 17 C (sorry I'm too lazy to do the conversion back for you_ why you guys didn't go metric years ago is beyond me), suffice to say this is about 1C below recommended minimum and the sulking little creatures almost stopped working. In the secondary the kraeusen reappeared and simply didn't want to go. I guess they liked it there! I was beginning to think I was going to have to beat it down with a mallet but eventually it saw reason and departed of its own accord (some ten days in the secondary). I was going to contact Chris at White Labs, not that I had a problem with the resulting beers but just to ask if this is the norm. Sorry I can't add much more, just interested to hear of someone experiencing something similar. If I spent less time being such a naughty recalcitrant I might have learnt something! One more point, save me writing another post. Fouchey mentions his mate Fred wants to re wire his pleasure toys to 415V for use over here. Well Eric, they usually only give us 240V in the home so unless he wants to play with the things while hanging on to the actives outside, tell him he's going to find them a bit dull. And whilst I've got your attention, would you please stop sending me these silly notes about cutting out paper dolls, you're making me laugh when I'm trying to concentrate on my lessons! Phil Yates. Return to table of contents
Date: Sat, 15 May 1999 05:25:34 -0700 From: John_E_Schnupp at amat.com Subject: stir plate Here's something to consider, it is very easy to build your own stir plate. Use a fan or motor, attach a magnet and you are on your way. You will need to build a case for it and will need something for speed control. If you use a DC fan/motor, use a variable voltage DC power supply. If you use an AC fan/motor, use a variac (variable AC transformer). I found a dearly departed stir plate at work and took it apart (just to see what made it stir, besides that's my job, take broken things apart, fix the broken thing and put it back together). It was a Corning(tm), it used an AC motor and was controlled by a variac. The stir plate I built used a DC fan and a recent upgrade uses a DC motor. You can make stir bars from nails. Cut the head off the nail seal it in some nylon/vinyl/teflon tubing. Be careful when heating/melting the tubing to seal the nail, you don't want it to catch on fire. Dave Burley gave me the nail stir bar idea (and a good idea too, IMO). You can build a stir plate yourself for almost nothing, especially compared to the cost of a new one. Even if you have to buy most of the stuff it will most likely be cheaper than a commercially produced stir plate. John Schnupp, N3CNL Dirty Laundry Brewery Colchester, VT 95 XLH 1200 Return to table of contents
Date: Sat, 15 May 1999 09:03:25 EDT From: JPullum127 at aol.com Subject: catales yes everyone knows cats are wonderfull, especially broiled with a little garlic butter and accompanied by a catamount porter. sorry i just could't resist,won't ever post anything like it again honest! Return to table of contents
Date: Sat, 15 May 1999 09:11:51 -0400 From: "Fred L. Johnson" <FLJohnson at worldnet.att.net> Subject: Wyeast 3068 Herb (Bresler?) describes the behaviour of a Weihenstephan Wheat yeast (Wyeast 3068) ferment and asks why the mat on top isn't falling after the ferment appears to be pretty much done: Your discription sounds pretty typical from my own experience with this yeast. The krauesen head on this fermentation is, indeed, impressive. I have had a 5.2 gallon ferment crawl out of a 6.5 gallon bucket on numerous occasions at 68 F. I think it is so vigorous that it is difficult to keep the internal heat down. I now ferment this well below 65, but I suspect the acual internal temp is considerably higher. I am working down in temperature from batch to batch and have noticed that the ferments are, of course, taking longer and longer but are becoming controllable at these lower temperatures. Regarding the mat of yeast that never falls. I have often racked after a week in the primary when there is still a good head on it and a moderate amount of activity. The activity continues for a while after racking (with longer time required with the lower temps, of course, before the activity gets REALLY slow.) The beer KEEPS its head in the secondary and at least some of the yeast remain in suspension (and probably in the head) longer than any I've ever worked with (limited experience, though). I finally bottle it at this point even though the beer has not cleared. To summarize, I think that the head is SO stable that it simply holds onto the yeast caught up in it, never really giving the yeast the opportunity to fall. I have always bottled this beer when the activity is low (not stopped) AND added plenty of priming sugar for HIGH carbonation--a characteristic of wiezens. However, I wonder if the high carbonation level characteristic of the style is historically the result of the typical behavior of this and, perhaps, other weizen yeasts. I guess I'm wondering if bavarian weizen brewers have historically not waited for all the fermentation to be complete with this style before bottling (because of the behavior of the yeast) and as a result end up with high carbonation levels. (Any Weizen history experts out there care to comment?) Incidentally, you may have read the recent posts that describe how the yeast eventually DOES fall out after weeks in the bottle and the beer actually becomes as clear as any other. Also, you may have read that many (or perhaps even most) weizens in bavaria are clear. - -- Fred L. Johnson Apex, North Carolina USA Return to table of contents
Date: Sat, 15 May 1999 10:12:26 -0400 From: "Fred L. Johnson" <FLJohnson at worldnet.att.net> Subject: Yeast culture in stirring flask Domenick Venezia recently commented on stirrers for yeast culturing, etc. I would like to ask Domenick and any others out there for some suggestion. I am trying to improve my technique for culturing yeast starters. I have been culturing in erlenmeyer flasks with a "long" foil cover over the mouth, starting with relatively small volumes and stepping up to 2 liters. I have had difficulty aerating the wort sanitarily. I have successfully used an airstone and 45 micron filtered air from an aquarium pump in these flasks but recently had my starter for the Big Brew '99 become sour. I am confident that my problem is in unclean aeration and/or repeated entrance into the flask(s). I recently picked up like-new $450 (retail), 12"x12" hotplate/stirrer at a flea market for 15 US dollars! (Boy, was I gloating!) I would like to believe that I can initially aerate the culture medium by vigorous stirring and also would like to believe that I can continue to aerate the medium (to maximize yeast growth) by continuous gentle stirring to achieve continuous gentle aeration. Is this reasonable? Or will the fermentation prevent additional air from getting into the wort? Perhaps I can force air into the flask during fermentation by putting the airstone ABOVE the medium, but I fear that the airpump could be a source of contamination. (Of course, with continuous aeration/yeast growth, the idea is to decant the spent culture medium before pitching.) - -- Fred L. Johnson Apex, North Carolina USA Return to table of contents
Date: Sat, 15 May 1999 16:26:45 +0200 From: "Dr. Pivo" <irv at wireworks.se> Subject: More eastern sounds that are beer related, and probably nobody cares about. > the pinyin form is not widely used there > as far as I know. Actually it is the "most" used form of transcription, it's just that "the most" used is still "not much". Even very educated people who can "read" pinyin, have to try their way "through the tones" before they understand what the hell is written. After all, they already have a written language that works straight across the dialects (you should see market places, where people with mutually non-intelligable dialects come together... they "write" the symbols with their fingers on the palms of their hands like crazy, and think you're pretty thick when you don't understand that), why should they learn another one? > Keyi geiwo yi bei pijiu ma? xiexie ni. Bu yao y bei. Yao liang ge PIN! Dong bu dong? > peeh tzee-oh' much like the 'eo' in Oreo I like your "oreo" dipthong, but not your "tz". I'd put it more at "tj" or "dj", a very explosive "j", much like the Indonesian one. The "tz" sound is more near the "c" spelling, if I recall correctly. And naturally, in Beijing, it never hurts to put a sort of "american" swallowed "R" at the end. But then again, does anyone really care? >The "Zh" sound is very different from the "j" You're right there. The "zh" is very "voiced", as in "Guanzhou" (or "Canton" to Dave). Speaking of more "cool spellings" and "sounds", did you know that in the Greek alphabet, they don't have a "B", so that "borrowed words" with "b"'s (like beer) are spelled "mp" instead. Try it, it almost "works". I just love almost spitting in their faces when I ask for one. "polykalo......mmmmmMMMMMMPPPIR!!!". Makes me almost wish I had a stutter. Speaking of Greek beer, they have a tonne of licensed brewed stuff (Loewenbrau, Amstel, etc.) that all taste like "Hellas Fix" (no big deal). But if on Cyprus ( Eng.sp?), it's well worth scooting over to the Turkish side and loading up with "Effes". A lovely little hop "ring" in that. Dr. Pivo Return to table of contents
Date: Sat, 15 May 1999 10:29:16 EDT From: Bobpreed at aol.com Subject: Primetab I've been thinking about using the Primetab corn sugar tablets for bottle conditioning, has anyone had any experience with Primetab, either good or bad? Thanks. Return to table of contents
Date: Sat, 15 May 1999 16:22:55 +0000 From: AJ <ajdel at mindspring.com> Subject: Titratable Acidity/Phosphate John Wilkinson asked about measurement of titratable acidity. The specific question was over the end point of the titration. The smart answer is that the end point is arbitrary - it can be any pH you like. In titration of water for alkalinity it is acceptable (per APHA/AWWA standards) to do this with the caveat that you note the pH you used. This is a pretty sorry state of affairs, especially for a standards organization and so there are other ways of approaching the problem. In measuring titratable acidity the indicator is almost universally phenolpthalein which is declared to change color at pH 8.4 and so that is the pH to which one should titrate when using a meter to be consistent. Most of the pK's for the acids being checked for in TA are much lower than this so that there will be little error induced if one used 8.3 or overshoots to 8.5 -- that's why you can get away with using an indicator rather than a meter and still get a good result. Other definitions are based on the "equivalence point" where the number of milliequivalents of the titrant are equal to the number of the substance being tested for. In measuring alkalinity one can compute the equivalence pH (once the alkalinity us known or approximately known) because the test substance in bicarbonate with known pK. In titratable acidity one can't do this because you don't know how much tartartic, how much succinic, how much malc.... are involved. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Don't get scared, I'm not going to discuss any of the phosphate issues here any further. I have replied to Matt Brooks privately and suggested that further discussions be carried out off line. I'll be happy to copy anyone who is interested in staying with this thread. I will note that a simple experiment with an equimolar phosphate buffer (pH 6.8) to which calcium chloride solution was added gave a dense precipitate and immediate pH drop. (Someone else posted about getting the ppt. but no change in pH. ???). The interesting thing here is that when the ppt. was washed and centrifuged two distinct solid phases were seen in the tube. Thus more than one form of phosphate precipitated. One phase was gelatinous and the other just wet powder. - -- A. J. deLange Numquam in dubio, saepe in errore. Return to table of contents
Date: Sat, 15 May 1999 13:44:45 -0400 (EDT) From: Joe Rolfe <onbc at shore.net> Subject: Is it just me....or is Jethros "reports" always unreadibly formatted....? Return to table of contents
Date: Sat, 15 May 1999 17:52:56 EDT From: AKGOURMET at aol.com Subject: HERMS Piping My project this past winter was building a heat-exchange RIMS and I finally got it fired up for a 10 gallon batch last month. It's a 2-tier set up with a 48 qt. cooler for the mash tun, a magnetic drive pump, a 1/2"x10' copper coil in the sparge kettle and a combination of rigid 1/2" copper pipe and 1/2" high temp. flexible tubing (from Moving Brews). It's a tight fit, but if you heat up the end of the tubing in boiling water it will slide over the 1/2" copper pipe. I use the flexible tubing between the mash tun and the pump (~1 foot), between the pump and the sparge kettle coil (~6') and between the coil and the return manifold (~2') in the mash tun. I decided to use flexible tubing for 3 reasons: 1. flexibility in design. I don't know about you, but when I build something for the first time I almost immediately start redesigning it after the first use. About the 3rd. generation of something is when it really starts to gel. What I found out on this run was that I should have used a 15 foot coil in the sparge tank instead of 10. It takes longer than I want to ramp the temperature up. 2. flexibility in the joints. Especially around the pump. If the pump is tied in with rigid pipe, I could see vibration or a couple of accidental bumps causing a leak or a broken pump housing. It is also easier to take apart and clean with the soft tubing. 3. you can see thru the flex. tubing and watch the liquid turn from cloudy to clear. Not functionally necessary, but cool. As for the pump pulling a vacuum and collapsing the hose, I don't think that's a big concern. The tubing I have is pretty thick walled and reinforced with kind of a fabric weave. You'd have to pull a pretty good vacuum. I also wired my pump thru a ceiling fan dimmer switch so I can throttle back the flow (at half speed for about an hour the motor was barely warm to the touch). I was more worried about setting the grain bed instead of collapsing the tubing, so I soldered in a vertical piece of pipe in the mash tun manifold (slotted copper) so if the bed started to set, the vertical tube would suck air causing the pump to cavitate which would warn the operator to back off on the recirculating. Here's a question for the collective: what's the formula for figuring the volume of a cylinder in fluid ounces ? or to be more specific, how many ounces of liquid are in 19 feet of 1/2" tubing? Bill Wright Juneau, Alaska Return to table of contents
Date: Sun, 16 May 1999 01:07:29 +0000 From: AJ <ajdel at mindspring.com> Subject: diacetyl mouthfeel Dave Kerr asks if diacetyl could be responsible for an oily mouthfeel in a pFramboise. Diacetyl is often described as having a "slick" mouthfeel but I have never experienced that even with the high levels I've experimented with. How about other people? Since high levels of diacetyl usually come from "sarcina sickness" I've sometimes wondered if this slickness isn't from slime from the diacetyl producing bacteria (of which pediococcus is one) rather than the diacetyl itself. On another note, I've now measured Budweiser (Budvar) and found its diacetyl level to be 0.21 mg/L, just about the same as PU's (0.20 mg/L). In the Budvar I find the diacetyl harder to taste - the beer is not, IMO, as nutty or caramelly as PU. It's major quality seems to be sulfur. While not as pronounced as in PU, the caramel component is, nevertheless, present, especially as the sample warms at which time one can smell the diacetyl though it is hardly overwhelming. - -- A. J. deLange Numquam in dubio, saepe in errore. Return to table of contents
Date: Sun, 16 May 1999 14:46:18 +0930 From: Brad McMahon <brad at sa.apana.org.au> Subject: Label Fixing Brett Spivey, in his post appearing in HBD#3030 talks about using milk as a glue. He said: << Milk! Yep, good old milk. Whole, 2%, 1%, Skim, whatever. nobody knows why but it sticks tight as a drum while dry and then floats off in a ten minute soak of warm water (one said he mixed 100 ppm chlorine bleach and sanitized while de-labeling). "Don't soak the thing, just wet the back and stick it on - works like a charm." was the most convincing comment. I really like the idea of this method and if it works, will go this direction. >> Nobody knows why?? OK, I'm a nobody, and I know why. Milk contains casein, which is a natural adhesive. Caseinate glues are available on the market, used a lot in the arts. Check the labels on some of your glues, you may see it on there. Brad McMahon, An Australian who has never swung a cat by the tail. (You grab them by the neck, snake style, so they can't turn and bite.) Return to table of contents
Date: Sun, 16 May 1999 08:57:49 -0400 From: "Roy E. Dawson" <dawsonandassociates at on.aibn.com> Subject: Ruddles Best Bitter and Stone's Best Bitter. I am trying to brew facsimilies of Ruddles Best Bitter, and Stone's Best Bitter. Can anyone advise me: 1) what causes the uniqueness of their flavour, as compared to other English bitters; 2) what types of malt, hops, and yeast do they use. If anyone has a recipe, it would be greatly appreciated. Roy Dawson. Return to table of contents
Date: Sun, 16 May 1999 09:58:38 EDT From: ThomasM923 at aol.com Subject: Yellowing leaves In HBD #3028 Paul Shick wrote: "Last year, my bines had a bit of yellowing in the leaves, especially in the late summer..." Where were these leaves located? On the lower portion of the vine or all over? Sometimes you will see the lower leaves of a plant turn yellow and even drop off. This can be due the change in the level (intensity) of sun light over the growing season. The lower leaves were created earlier in the season and were adapted to a certain level of light. They cannot adapt later on to some other light level (more or less) so the plant allows them to die back and grows new leaves adapted to the new light level somewhere else on the plant. I would like to point out that I am making a generalization; I am sure there are plenty of exceptions to the phenomenon I just pointed out. I have never grown hops, but I don't think that they are that different from most garden plants. Thomas Murray Maplewood, NJ Return to table of contents
Date: Sun, 16 May 1999 07:54:58 -0700 From: Domenick Venezia <demonick at zgi.com> Subject: Re: Yeast culture in stirring flask On Sat, 15 May 1999, Fred L. Johnson wrote: > I recently picked up like-new $450 (retail), 12"x12" hotplate/stirrer at a > flea market for 15 US dollars! (Boy, was I gloating!) I would like to > believe that I can initially aerate the culture medium by vigorous stirring > and also would like to believe that I can continue to aerate the medium (to > maximize yeast growth) by continuous gentle stirring to achieve continuous > gentle aeration. Is this reasonable? Or will the fermentation prevent > additional air from getting into the wort? Perhaps I can force air into the > flask during fermentation by putting the airstone ABOVE the medium, but I > fear that the airpump could be a source of contamination. Fred, The flask mouth covers that I have seen are inverted stainless steel cups with pressed ridges to keep the bottom and sides of the cup from sealing against the flask neck. Anything that mimics this function should work. A drinking glass with foil rolls in an 'X' to keep the glass from sealing the flask mouth come immediately to mind. The farther down the neck the cover extends the better. You want free atmospheric diffusion up and into the flask but not violent enough airflow to carry any dust or other airborne particulates into the flask. These covers work well in a lab with vigorous air conditioning, so it seems to me that the concept is sound. The covers need to be sanitized just like the flask. Since aerobic cultures are grown like this in the lab I guess it works. Seems that when it counts O2 will be able to diffuse in. During the height of the fermentation the diffusion gradient of O2 may be offset by the physical exit of CO2, but until and after that it has to be more aerobic than an airlocked system. It's just my personal opinion, but I would avoid the hassle and risk of using an airstone in a starter. Though why I feel that way about starters and not fermenters is puzzling. I do use an airstone to initially aerate the wort before pitching. I actually have a first round starter flocculating now. You have got me thinking that I might break out my stirrer and follow my own suggestions for the first and second rounds (decant, refresh). Also, IMHO, the larger and better aerated your starter the less need there is for fermenter aeration. O2 is used to build cell walls (ergosterol) and cell walls only get "diluted" by reproduction, so if you pitch enough yeast to obviate the need for reproduction, then fermenter aeration becomes irrelevant. It's an idea (huge starter, no aeration of main wort) that I have been too timid to try. Perhaps next batch. Since I don't brew all that often, spending 2-3 weeks building a huge starter wouldn't be that much of a hassle. Cheers! Domenick Venezia Venezia & Company, LLC Maker of PrimeTab (206) 782-1152 phone (206) 782-6766 fax orders demonick at zgi dot com Return to table of contents
Date: Sun, 16 May 99 11:20:37 PDT From: "George De Piro" <gdepiro at fcc.net> Subject: Re: quick weiss question Hi all, Mark asks both the digest and me (in private) about Kraeusening Weizenbier. I have never Kraeusened a Weizen with a lager yeast. I never saw the point because I don't filter out the Weizen strain. The only problem might be that you would get some excessive H2S in the beer (since lager yeasts are good at making this). It is also difficult to control the carbonation level because unless you can precisely measure the gravity of the Kraeusenbier at the time of addition, and know its final gravity, you won't know how much to add. This can be done, of course, if you have a good hydrometer and the knowledge of the wort's fermentability. Doing all of this in a sanitary manner is a bit tricky, but again, it can be done. Make up more Kraeusen wort than you expect you'll need in case the wort is more fermented than desirable when you get around to adding it to the main batch. Many German breweries simply feed the young Weizenbier fresh wort ("Speisse"). This is what I usually do, and it works great. Keep in mind that if you prime or Kraeusen with a wort other than a Weizen wort, you will be altering the percentage of wheat in the final beer. Have fun! George de Piro (all over eastern NY state...) Head Brewer at The Albany Pump Station Malted Barley Appreciation Society "Brooklyn's Best Homebrew Club" http://hbd.org/mbas Return to table of contents
Date: Sun, 16 May 1999 21:40:08 EDT From: JYANDERS at aol.com Subject: Medicine Rock Keg I am thinking about purchasing a 2.5 gallon Medicine Rock Keg. Before I do though, I would like to ask the group if anyone has had any experience with this devise. JMA Return to table of contents
Date: Sun, 16 May 1999 21:50:48 -0400 (EDT) From: Some Guy <pbabcock at hbd.org> Subject: 2000 AHA Home Brewers' Conference Greetings, Beerlings! Take me to your lager... How many out there, like Mike, don't believe I really exist? That, perhaps, I'm just a cyber personality that lives only in the imagination of some server? Here's your chance to prove, once and for all that "Yes, Virginia: there IS a Pat Babcock!" How 'bout the 200 AHA conference in the Detroit area? No way I could avoid it, then. Suggest it to Brian and Paul... See ya! Pat Babcock in SE Michigan pbabcock at oeonline.com Home Brew Digest Janitor janitor@hbd.org HBD Web Site http://hbd.org The Home Brew Page http://oeonline.com/~pbabcock/brew.html "Just a cyber-shadow of his former brewing self..." Return to table of contents
Date: Mon, 17 May 1999 06:59:50 +0200 From: "Aikema, J.N. (JohanNico)" <JohanNico.Aikema at akzonobel.com> Subject: bacteria Hi, A question for the microbiologists amongst us. I checked a starter yeast sample for a member of our homebrewingclub yesterday with my microscope. The sample was from a British commercial brewery. Next to a few yeastcells, I found VERY lively lactobacilli like rods (I think a little smaller than lactic acid bacteria). Probably with whip-tail ~ (I don't know the right translation). Is there anybody who can give me a suggestion about the type? I'm looking for pictures of yeast cells and bacteria on the web. Any suggestions? Greetings from Holland, Hans Aikema http://www.cybercomm.nl/~aikema/ Return to table of contents
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