HOMEBREW Digest #4950 Sun 12 February 2006

[Prev HBD] [Index] [Next HBD] [Back]

		Digest Janitor: pbabcock at hbd.org


          Northern  Brewer, Ltd. Home Brew Supplies
Visit http://www.northernbrewer.com  to show your appreciation!
               Or call them at 1-800-681-2739

    Support those who support you! Visit our sponsor's site!
********** Also visit http://hbd.org/hbdsponsors.html *********

  RE: metallic flavor in first keg beer ("Peter A. Ensminger")
  Re: Yeast and oxygen ("Fredrik")
  Re: Metallic Taste In Corny Keg (Dan Jeska)
  RE: softened water in brewing ("Martin Brungard")
  Hop Isomerization ("Martin Brungard")
  Delirium Tremens (goetzr1)
  Re: metallic flavor in first keg beer (Derek Sheehan)
  secondary fermentation (Rick Weber)
  rice hulls and oak ("D. Clark")
  metallic taste in reconditioned keg (Aaron Martin Linder)

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * The HBD Logo Store is now open! * * http://www.hbd.org/store.html * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Suppport this service: http://hbd.org/donate.shtml * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Beer is our obsession and we're late for therapy! * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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 FROM THE E-MAIL ACCOUNT YOU WISH TO HAVE SUBSCRIBED OR UNSUBSCRIBED!!!** IF YOU HAVE SPAM-PROOFED your e-mail address, you cannot subscribe to the digest as we cannot reach you. We will not correct your address for the automation - that's your job. HAVING TROUBLE posting, subscribing or unsusubscribing? See the HBD FAQ at http://hbd.org. LOOKING TO BUY OR SELL USED EQUIPMENT? Please do not post about it here. Go instead to http://homebrewfleamarket.com and post a free ad there. The HBD is a copyrighted document. The compilation is copyright HBD.ORG. Individual postings are copyright by their authors. ASK before reproducing and you'll rarely have trouble. Digest content cannot be reproduced by any means for sale or profit. More information is available by sending the word "info" to req@hbd.org or read the HBD FAQ at http://hbd.org. JANITORs on duty: Pat Babcock (pbabcock at hbd dot org), Jason Henning, and Spencer Thomas
---------------------------------------------------------------------- Date: Sat, 11 Feb 2006 00:20:33 -0500 From: "Peter A. Ensminger" <ensmingr at twcny.rr.com> Subject: RE: metallic flavor in first keg beer Hi Aaron, I have been using corny kegs for many years and have employed the "high pressure/shaking method" and the "sit and wait method". My beer is never perfect, but I have never detected a metallic flavor. BTW, I am a Beer Judge, so I've tasted lots of weird stuff over the years. First thing that comes to mind is that your beer is oxidized. This can manifest as a metallic flavor. But I would be surprised if this develops over a mere 2-3 days. Another possibility is that your cleaning/sanitizing routine is to blame. I typically use PBW, an alkaline cleaner, followed by StarSan, an acid sanitizer (NAYYY). This is not the cheapest way to prep your kegs, but it has never failed me. Cheerio! Peter A. Ensminger Syracuse, NY Beer data: hbd.org/ensmingr Apparent Rennerian: [394, 79.9] Return to table of contents
Date: Sat, 11 Feb 2006 11:43:19 +0100 From: "Fredrik" <carlsbergerensis at hotmail.com> Subject: Re: Yeast and oxygen > Date: Fri, 10 Feb 2006 14:49:59 -0800 > From: "Peed, John" <jpeed at elotouch.com> > Subject: Yeast and oxygen > > > OK, I never did quite get the scoop on yeast oxygenation. All the fuss > with oxygenation seems to center around pre-fermentation oxygenation to > build the cell walls. But that begs the question: Why does stirring on > a stir plate for the duration of starter fermentation make a starter > ferment so much more rapidly and build more yeast? Also, if you pitch > the whole thing after stirring for a day, do you risk oxidation? My > experience says no. Why not? > > John Peed > Oak Ridge, TN FWIW, the way I understand it... Stirring or shaking a container with headspace oxygen, speeds the uptake of oxygen from the headspace, as well as stimulating the culture, and possibly reducing the level of CO2 supersaturation. I read a paper (don't remember the reference from the top of my head, but if someone wants please ask and I might search for it) where it was confimed that in a stirred fermentation (brewers don't normally do this), the amount of headspace significantly affected the isoamylacetate level formed, and the difference was not marginal, it was a factor x5 between extrems if I remember correct, presumably because stirring in a air atmosphere amounts to a kind of later aeration. There was no oxygen injection, the "aeration" was only regulated by menas of the fermentor headspace, nothing else. And of course there was stirring in both cases. Also, better cellemembranes gives higher fermentation performance and higher biomassyield. Of course if the headspace is infinite like stirring an open ferment without lid, when the glucose repression ceases maybe one might see some elevated degree of respiration. But I think this is not normal procedures. The initial aeration builds the initial quality of the membranes, but as soon as the anaerobic reproduction sets in, the cellmembranes are deprived of UFA's and sterol because the mother shares with the daughter cells. This is the simple reason why yeast don't reproduce more than maybe the order of 5 generations anaerobicayll - at that point the quality of the cellmembrane is simply unacceptable. Of the exact point of unacceptable would depend also on simulatenous stresses. Combine that sterol/UFA depletion with strong alcohol and osmotic stress and I'm sure it will poop out earlier. Somehow the total accumulated stress on the yeast has an impact. All else beeing perfect, yeast can withstand much higher ethanol than if it's put to a range of simultaneous stress. About the significance of flavour due to various oxidation I don't have much comments at this point. My limited experience is that when you aerate the culture with high ethanol I tend to quite quickly feel elevated ethanol oxidations, because ethanol + oxygen, and without glucose repression might reverse things and yeast might try to respire on the ethanol. I recall reading another paper some year/s ago where it was found that yeast has some not identifies pathways for dissipation of oxygen, that aren't related to respiration nor UFA/sterol synthesis. I still don't have a clear picture on this, maybe Steve or someone else can fill in. I am currently working on my understanding here. /Fredrik Return to table of contents
Date: Sat, 11 Feb 2006 08:32:42 -0500 From: Dan Jeska <dan.jeska at gmail.com> Subject: Re: Metallic Taste In Corny Keg Aaron Linder reports a metallic taste in a reconditioned corny keg he just purchased. Aaron, I would completely disassemble any corny keg, whether reconditioned or not, fill the keg and soak all the parts in a PBW solution before putting it into service. Perhaps apply a brush to the dip tube, poppets and posts. My experience with PBW is "it gets rid of everything that doesn't belong there". Dan Brewing at (85.5, 277.7) Rennerian Return to table of contents
Date: Sat, 11 Feb 2006 07:02:05 -0900 From: "Martin Brungard" <mabrungard at hotmail.com> Subject: RE: softened water in brewing I liked Steve Alexander's question in the form of a major treatise on chemistry. AJ's response to Steve's question regarding the use of ion-exchanged softened water in brewing was also very complete. I echo AJ's comment about using softened water. Why use a water that could have a potentially detrimental taste impact when the naturally hard water is generally better for brewing and doesn't have a negative taste impact. Steve pointed out correctly that he replaces calcium ions with sodium at a rate of 1 to 1.15 (Ca to Na). We need to remember that ion-exchange softeners also replace magnesium at a rate of 1 to 1.89 (Mg to Na). Most drinking waters tend to have substantially more Ca than Mg, so the higher Mg replacement rate with sodium is less of an impact. But, the combined impact of replacement can be significant depending upon the starting hardness of the base water. To put the effect into prospective, lets assume that people would want to use a softened water when their water hardness is greater than about 120 ppm as CaCO3. For that water, ion-exchange softening will drop the hardness substantially and increase the sodium content by about 40 ppm. Forty ppm of sodium is definitely a flavor impact, and that's just for a moderately hard water. It only gets worse for harder waters. Steve is right, there are plenty of beer styles that would not have a detrimental result with 40 to 60 ppm sodium, but there are plenty of other styles that wouldn't be so successful. Steve is right, a blanket statement that ion-exchange softened water can't be used in brewing shouldn't be made. But the cautions that I make in this post should also be heeded and most brewers would make better beer with hard water instead of ion-exchanged softened water. Martin Brungard Tallahassee, FL Return to table of contents
Date: Sat, 11 Feb 2006 08:35:07 -0900 From: "Martin Brungard" <mabrungard at hotmail.com> Subject: Hop Isomerization John Peed recently posted an item regarding hop isomerization that should be expanded upon. John mentioned that hop isomerization was dependent upon mechanical mixing and heat, as in a good rolling boil. Unfortunately, this is a brewing momily that is both true and false on several levels. Let's first explore the need for mechanical mixing. Mechanical mixing via a rolling boil is not always needed. This is dependent upon the form of the hops used in brewing. Pelletized hops have been in use for several decades now. A rolling boil is not needed when pelletized hops are used. There are several reasons why pelletized hops don't need the rolling boil. The first reason has to do with the methodology used to assess the alpha acid content of all hop products. The ASBC and EBC methodologies both require that whole hops be fully mascerated (ground up) prior to testing. This is because the lupulin glands in the whole hops need to be ruptured to expose the lupulin. Please note that this is the condition that pelletized hops are in. Whole hops do require a rolling boil in order to help expose and burst the lupulin glands. But the degree of the exposure and the degree to which the lupulin glands were burst during harvesting and packing will always be in question. The degree of utilization of alpha acids is very much in question when using whole hops. Brewers recognize that an increased utilization is applied when using pelletized hops. Given the hop alpha acid testing methodology, its apparent that we should relate the utilization of whole hops as an under-utilization instead of relating an over-utilization for pelletized hops. Recent research by Malowicki and Shellhammer confirms that alpha acid isomerization is soley dependent upon the wort temperature and time. For boiling wort, the intensity of the boil doesn't change the wort temperature. Therefore, its can be stated that the intensity of the boil does not affect isomerization when the alpha acid (lupulin) is fully exposed. I hope this illustration helps brewers understand that a really active boil isn't really needed, except when using whole hops. Martin Brungard Tallahassee, FL Return to table of contents
Date: Sat, 11 Feb 2006 22:36:58 +0000 From: goetzr1 at comcast.net Subject: Delirium Tremens Looking for a Delirium Tremens extract clone with steeping recipe. Thanks Return to table of contents
Date: Sun, 12 Feb 2006 08:34:52 -0500 From: Derek Sheehan <w7rex at comcast.net> Subject: Re: metallic flavor in first keg beer Aaron, I started kegging a few years ago and have found it to be incredible. No more cleaning all those bottles! As far as your metallic flavor, I have noticed that some re-conditioned kegs have lids with a little rust in the pressure relief valve assembly. At least the stuff I have found is dark like rust and has a very sharp metallic taste. I contribute this to the spring valve rusting somewhere. A dowel with a bit of green scrubby on the end gets the crud out and I replace the offending spring plunger. Kegs have lots of cracks and spaces that are hard to clean and you have to be very vigilant to get them clean and sanitized. We should get together sometime, brew and split a batch! Derek in Dexter Return to table of contents
Date: Sun, 12 Feb 2006 12:28:41 -0600 From: Rick Weber <rick.weber05 at gmail.com> Subject: secondary fermentation Hey, Two questions: First, I don't seem to get any change in specific gravity after I rack my beer to the secondary fermentor; why? I generally rack about 4 or five days after it goes into the primary, when the krausen has fallen and the airlock burps about once every 10 seconds. Second, my original gravities have been much higher than expected with higher alcohol output than expected also. I just bottled a batch of a brown ale (Theakston's Old Peculier) and got an alcohol output of 9.4% compared to an expected 6.2% in Clone Brews, the original gravity was, if I remember correctly, about 0.015 higher than expected. Thanks for the help, Cheers! Rick - -- "Education: The ability to listen to almost anything without losing your temper or self confidence." - -- Robert Frost Return to table of contents
Date: Sun, 12 Feb 2006 13:36:18 -0500 From: "D. Clark" <clark at capital.net> Subject: rice hulls and oak Hi list, I brewed up a wheat beer Saturday using rice hulls for the first time. I had a pound bag, so I tossed about half into my mash. No problems mashing and the sparge went off without a hitch. Thanks for the help. With all the talk of oak barrels or adding oak chips or flakes to beer, it raises the question of what styles of beer would benefit from the oaky flavor. I would think primarily ales and Belgian styles but also stouts and porters. Oak chips are available everywhere for adding to wine, but if they were to be used in beer, when would you put them in? Would they go into the boil, primary or in the secondary? Just food for thought. Back to water again. I have sent samples of my very hard well water and some spring water to be tested. I made the wheat beer with the spring water this time. I preheat my sparge water on the woodstove in the name of efficiency, and it will generally boil for a while before I am ready to use it. Usually there will be a big load of a tannish colored precipitate with my well water, but this time there wasn't a speck of anything floating around. I think that will bode well for this beer. I'll post the test results for comment when I get them. Happy brewing. Dave Clark Eagle Bridge, New York Return to table of contents
Date: Sun, 12 Feb 2006 19:37:08 -0500 (EST) From: Aaron Martin Linder <lindera at umich.edu> Subject: metallic taste in reconditioned keg Hi, This is a followup post to point out the most likely source of a mild metallic flavor in my first kegged beer. I originally purchased three reconditioned, acid-washed kegs from SABCO. The first I rinsed thoroughly with water and used as is. I inspected the second two today and found that I could smell a faint metallic odor coming from the empty keg. So, I rubbed some tissue on the inside of the kegs, and sure enough there was a gray, very fine residue on the tissue! ----! I should have paid more attention the first time. Anyway, I thoroughly scrubbed the two remaining kegs with detergent and rinsed them. they lost their metallic odor. I guess this shows that one shouldn't be lazy or careless at least. I don't know what the residue was. Perhaps a layer of metal oxide leached off of the keg after SABCO's processing. aaron linder Ann Arbor, MI Return to table of contents
[Prev HBD] [Index] [Next HBD] [Back]
HTML-ized on 02/12/06, by HBD2HTML v1.2 by KFL
webmaster@hbd.org, KFL, 10/9/96