HOMEBREW Digest #4878 Tue 01 November 2005

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  Re: Google map for HBD readers? (Nathan J. Williams)
  Re: Continuous aeration of starters (Fred Johnson)
  Re: Continuous aeration of starters ("Thomas T. Veldhouse")
  Beer Map (Google map for HBD readers?) (Alexandre Enkerli)
  Evaporation rates (Francisco Jones)
  Continuous forced aeration of starters not necessary (ALAN K MEEKER)
  Aeration Foam ("carl sherman jr")
  HHHC Competition Announcement (Tim Fahrner)
  Attaching a spigot to the boiling pot. ("eric")

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---------------------------------------------------------------------- Date: 01 Nov 2005 01:02:32 -0500 From: nathanw at MIT.EDU (Nathan J. Williams) Subject: Re: Google map for HBD readers? Jeff Renner <jsrenner at umich.edu> writes: > Bob Devine <bob.devine at worldnet.att.net> wrote from Riverton, UT: > > > Suggestion: How about having a HBD reader page with a > > Google map on hbd.org? Did you ever want to quickly > > find people near you? Or see which club are close by? > > I don't know nothin' about how to do this kind of stuff, but I love > the idea (no surprise here). > > I hope someone will take a stab. The current "cool kids" web site for this kind of thing is frappr.com, which lets groups register a set of zip codes (or city/nation outside the US) and view the results as a Google map. If anyone wants to add themselves, I've created a Frappr map under the group name "hbd". http://www.frappr.com/hbd - Nathan Return to table of contents
Date: Tue, 1 Nov 2005 08:02:54 -0500 From: Fred Johnson <FLJohnson at portbridge.com> Subject: Re: Continuous aeration of starters Mike asks about how to maximize the benefit of continuous aeration of starters. To push the yeast into yeast cell mass production and away from alcohol production, the yeast must not be exposed to glucose concentrations greater than 0.4%. If the glucose concentration exceeds this threshold, the yeast will ferment the glucose into CO2 and alcohol regardless of whether oxygen is present or not. The only practical way to feed the yeast to avoid high concentrations of glucose is to continuously infuse the medium at a rate less than the yeast can use it, but you must also provide oxygen to maintain the growth. Otherwise, the yeast will ferment the glucose even at low concentrations. From Malting and Brewing Science: Mass (kg) -------------- Medium Conditions Yeast Ethanol Wort Unaerated 2.7 17.5 Wort Aerated 8.6 10.5 Wort Aerated Incremental Feed 23 0.7 Molasses Aerated Incremental Feed 50 0 ("Incremental Feed" in this case means repeated additions of progressively higher amounts of substrate but maintaining maximum levels of glucose below 0.4%. The ideal way to do this is to continuously infuse the substrate at a rate that is proportional to the mass and but no higher than will maintain glucose concentration at less than 0.4%.) - -- Fred L Johnson Apex, North Carolina, USA Return to table of contents
Date: Tue, 01 Nov 2005 07:50:31 -0600 From: "Thomas T. Veldhouse" <veldy at veldy.net> Subject: Re: Continuous aeration of starters Mike Sharp wrote: >Recent posts on yeast have gotten me to wonder about continuous aeration of >a starter. I use an Ehrlenmeyer flask on a mag stirrer, and I've been >thinking about using an aquarium pump with a sterile filter to continuously >aerate while I stir. However, if I understand things correctly (which would >be unusual in this subject area), this might not do me any good unless I >also continuously feed the yeast. Is that correct? If so, and since I >don't have a metering pump, could I approximate continuous feeding by giving >the yeast little wort snacks periodically? > > It has been my experience that you can get excellent yeast growth with just a charge of oxygen at the beginning, making the stir plate unnecessary as a matter of procedure. However, if you have the equipment, then using it is probably an added bonus. To get the air you need into the starter, it should be sufficient to simply put sterile cotton in the neck of your flask, or use another sterile filter if that makes you feel better. The action of the swirling wort/beer should be enough to draw air into the flask. Return to table of contents
Date: Tue, 1 Nov 2005 11:02:25 -0500 From: Alexandre Enkerli <enkerli at gmail.com> Subject: Beer Map (Google map for HBD readers?) Our good friend Ben provided this link for a beer-related Google Map: http://www.nhbrewers.com/mapbeer.html Awe-some! Now, would it be possible to add a category for homebrewers? Maybe hidden by default or some such, but it'd be incredibly nice to have that kind of visual aid. In fact, it'd be really neat to see how concentrated a beer scene might be, say, by how many brewers there are around a given brewpub... And for those who worry about privacy, there's surely a way to give a blank number for the address (say "Western Ave, Northampton, MA, 01060" instead of "14 Western Ave, Northampton, MA, 01060"). And, just imagine if one could do a Google search for, say "homebrewers near Medford, MA"! Ale-X in Bridgewater, MA http://dispar.blogspot.com/ http://www.livejournal.com/users/enkerli/ http://blog.criticalworld.net/ Return to table of contents
Date: Tue, 01 Nov 2005 10:39:26 -0600 From: Francisco Jones <frandog at earthlink.net> Subject: Evaporation rates Here's something I've been wondering about for a while: I'm a heavy user of Promash, and it allows you to set your boil-off evaporation rate by either quantity per time ( ie gal/hr), or percent per time (ie 5%/hr). I've been using the former, because using percent implies that the amount of water you lose in a given amount of time _changes_ as the volume in the boil pot changes. In other words, as the volume in the boil pot decreases, with the percent fixed, less water is lost in the next time increment than in the previous time increment. So boil-off is quadratic, or logarithmic, or whatever? Not linear? Why is that? This is not intuitive to me, since it seems like with a given flame and pot opening, etc, I should get the same loss per time increment regardless of the volume in the pot (ignoring boundary value cases such as when the pot is almost empty). Can anyone elaborate on why the percent method works, and which method is better or worse for particular situations? I'm guessing that for large boil volumes, and for small total boil-off, the gal/hr method is an approximation of the percent method. But I don't understand why. Though it just occurred to me that this may be analogous to the situation of using a larger propane tank to get increased gas output even though the (ambient) temperature of the liquid propane is the same for a small and a large tank. That is, more volume of liquid to liberate gas from? Thanks. Francisco Jones Kankakee, IL [256 magnetic/196 nm] AR Temporarily writing from Houston, TX [226/923nm] Return to table of contents
Date: Tue, 01 Nov 2005 12:20:32 -0500 From: ALAN K MEEKER <ameeker at mail.jhmi.edu> Subject: Continuous forced aeration of starters not necessary Mike Sharp asked about forced aeration and continuous feeding of yeast starters grown on a magnetic stir plate. Mike, this is not necessary. It's a waste of effort and, as a potential source of contamination, may do more harm than good. With mildly vigorous stirring and a loose fitting cover the starter will get all the oxygen it needs for healthy growth by the magic of diffusion. I was worried about the same thing when I started making starters on a mag stirrer but they grew up quite nicely. I also did an experiment that convinced me there was nothing to worry about. I made up a starter using glycerol instead of glucose as the sole energey source. Brewer's yeast cannot ferment glycerol, they can only utilize it by aerobic respiration, thus sufficient oxygen is an absolute requirement. The glycerol starters grew up well, indicating that they were getting plenty of oxygen just from the action of the stir plate. The continuous feeding you are referring to is used in industry to maximize the biomass (yeast) yield with glucose-fed yeast under aerobic conditions. The goal is to keep the glucose concentration down below the level which induces the Crabtree effect in which yeast will ferment glucose to ethanol even in the presence of oxygen. We homebrewers really should not be growing our starters up in glucose- based starter media, rather some sort of wort should be used. Wort is relatively glucose poor, so the yeast will quickly eat up the glucose and then enter into an aerobic respiration phase. This will also avoid the potential loss of maltose (the main utilizable sugar in wort) utilization capability which may occur in yeast cultures grown in media which only contain glucose as the sole energy source. This would obviously be a bad thing to lose going into the main wort fermentation. Alan Meeker Lazy Eight Nanobrewery Baltimore, MD Return to table of contents
Date: Tue, 01 Nov 2005 14:16:08 -0500 From: "carl sherman jr" <rsherman69 at hotmail.com> Subject: Aeration Foam Beginner, first post I am using an aquarium pump and stone to aerate my wort in the fermentor. I have read that you must wait for the foam to subside before pitching the yeast, but can not find any reasoning for this. During aeration, I have to stop before the foam comes out the top of the carboy. I have waited for the foam to subside, but this takes quite a while, and I am afraid of contaminating the wort. Should I seal the carboy with an airlock, and wait for the foam to subside. Should I pitch the yeast with the foam still in the carboy? I can't seem to find anything further on this subject. Any help will be appreciated. Rich S. Scranton, PA Return to table of contents
Date: Tue, 01 Nov 2005 14:37:28 -0600 From: Tim Fahrner <fahrner at pathology.wustl.edu> Subject: HHHC Competition Announcement Just a note to the readership that registration is now open for the 14th Annual Happy Holiday Homebrew Competition. Official announcement to follow: Have the ultimate holiday homebrew? Enter it and your other fine beers in the St. Louis Brews' Happy Holiday Homebrew Competition, one of the biggest homebrew competitions in the Midwest. This year it will be held on December 10, 2005 at the Parish Hall of Our Lady of the Presentation Catholic Church in Overland, MO. So you think your brew can be a contender? Find out by entering it in the HHHC 2005. It's AHA & BJCP sanctioned, and we are proud to be the final qualifying event for the Eighth Annual Masters Championship of Amateur Brewing. Please see our website, stlbrews.org, for more information. Vital details in brief: Fee: $5.00 Entry Deadline: 11/1/2005 - 12/3/2005 Awards Ceremony: 12/10/2005 Sanctioned by BJCP, AHA MCAB Qualifying Event Contact: David Nitzsche Phone: 314 918 1929 Return to table of contents
Date: Tue, 1 Nov 2005 19:32:50 -0700 From: "eric" <zeee1 at nebonet.com> Subject: Attaching a spigot to the boiling pot. Hello all I recently asked about stirring the cooling wort with the immersion coil, then pouring my cooled wort through a funnel. The replies suggest that siphoning or using a spigot would help to reduce: 1, the chance of contamination and 2, the amount of trub going into the fermentor. If I go the spigot route with a tig and stainless fittings, is it suggested to attach the fitting as close to the bottom as I can, assuming the trub will pretty much stay in the middle of the pot, or should it be mounted a little high? Threaded short piece of tubing for a thread on valve? I have been putting the funnel and strainer in sanitizer, then rinsing off and putting the coil, strainer, and funnel in the boiling wort for the last 10-15 minutes for sanitizing. Also, I am "rereading" Papazian. I also have a Dave Miller book. Any recommendations for others? Eric Deweyville, UT Return to table of contents
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