HOMEBREW Digest #3477 Mon 13 November 2000

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

		Digest Janitor: janitor@hbd.org


          Northern  Brewer, Ltd. Home Brew Supplies
        http://www.northernbrewer.com  1-800-681-2739

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

  HBD Servers On The MOVE! (Some Guy)
  Brewery business goes flat ("Shane A. Saylor, Eccentric Bard")
  Birded malt - and the feathers fly! (David Fisher)
  Personal experience with low gravity ferments (Mjbrewit)
  Tip for Pressure Cookers (james r layton)
  Re: R/O Water (Jeff Renner)
  Salts for Pilsner & Pale Ale from RO Water, And a Scale to Weigh Them (Ken Schwartz)
  Ring the Bull (Jeff Renner)
  Pre-packaged salts (GASNER)
  Salts ("A. J.")
  Zn solution - biological stability? ("Hubert Hanghofer")
  C'ya MidWest! Hello New Hampshire... ("Scott D. Braker-Abene")
  re: Low gravity/Burp ("Stephen Alexander")
  Thanks for helping ID keg type ("Dave Howell")
  Krupnik? (CeolNaFidhil)
  Enzyme Kinetics - part 3 ("Stephen Alexander")
  Lagering under pressure (BShotola)
  water filter harboring bacteria? ("Richard & Laura")
  Strange yeast formations ("Grant Stott")
  Some highly personal and unverified thoughts on pitching temperatures for lager yeasts. ("Dr. Pivo")
  RE: Tip for Pressure Cookers (Some Guy)

* * 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 canoot reach you. We will not correct your address for the automation - that's your job. 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 at hbd.org. JANITOR on duty: Pat Babcock and Karl Lutzen (janitor@hbd.org)
---------------------------------------------------------------------- Date: Sun, 12 Nov 2000 21:32:48 -0500 (EST) From: Some Guy <pbabcock at hbd.org> Subject: HBD Servers On The MOVE! Greetings, Beerlings! Take me to your lager... The HBD servers will (at least to current plans) be moving to their new location Thursday, 11/16/00. Expect an outage at this time, lasting for an indefinite time as DNS servers catchup with the change in IP address, etc. We will do everything in our power to minimize the amount the servers are down and/or unavailable with this move; however, there is a lot of network between you and me, and we have no control over how long it takes for the redirect to propagate to your local machines. Please have patience! Any questions or concerns should be directed to babcockp at mediaone.net during this move. Once the move is complete and email is once again functioning peoperly on the HBD servers, the cable modem will be shut down and babcockp at mediaone.net will no longer exist. At that time, you should be able to revert to using janitor@hbd.org for any questions, comments, etc... This message will repeat until the servers are moved. - -- - See ya! Pat Babcock in SE Michigan pbabcock at hbd.org Home Brew Digest Janitor janitor@hbd.org HBD Web Site http://hbd.org The Home Brew Page http://hbd.org/pbabcock "The monster's back, isn't it?" - Kim Babcock after I emerged from my yeast lab Saturday Return to table of contents
Date: Sat, 11 Nov 2000 00:19:46 -0500 From: "Shane A. Saylor, Eccentric Bard" <taliesin2 at earthlink.net> Subject: Brewery business goes flat Thought this story might be of interest... http://www.msnbc.com/news/481184.asp?0nm=B28G Return to table of contents
Date: Sat, 11 Nov 2000 18:36:17 +1100 From: David Fisher <david at colossus.apana.org.au> Subject: Birded malt - and the feathers fly! Thanks to all and sundry who offered advice on my Maris Otter avec bird. The advice received ranged from the entirely predictable Pythonesque lines about the the thing just sleeping ("The English Sparrow prefers kippin' in a bag of malt...") to the need for a longer than usual protein rest. Ho hum. The malt was cheerfully replaced by the retailer involved, gawblessim, unfortunately with Golden Promise as he was out of MO for the time being. On second thoughts, I am afraid I shall withhold my thanks from the individual or two who suggested using it. David Non-avian brewing in Ashfield, Sydney, NSW, Australia (Right-O, Jeff?) Return to table of contents
Date: Sat, 11 Nov 2000 10:32:23 EST From: Mjbrewit at aol.com Subject: Personal experience with low gravity ferments Low gravity fermentation is a subject of much debate. Maybe I can offer some advice from my limited experience. Two years in a row I attempted to brew a prize winning mild at 1.036. To make a long story short I chose to dilute after fermentation while kegging. The first attemp was OK, but there was a dominant oxidized flavor character, cardboardy and the beer tasted, well,... watery. I thought maybe it a was the yeast, so I tried it again with a different yeast. Nope, a similar cardboard profile was present in the second batch. I was cognizant of the potential for accidental oxygenation so I made sure I boiled the water and cooled it before adding it to the keg. I also took special care to minimize splashing during the transfer. The beer was OK, by definately not prize winning. I suggest using a 1.045 to 1.048 grain bill, and stop sparging at say 15% to 20% below your normal volume and then add water prior to the boil. Math is not my specialty, but your only looking for a range. Check the gravity before the boil and add DME if your too short. If your a little over your target, drain a little and add more water. This will require an estimate of how much will evaporate during the boil, that is easily measured in most systems. I will try this in two weeks and report back later. Mike B. Chicago Return to table of contents
Date: Sat, 11 Nov 2000 10:03:35 -0600 From: james r layton <blutick at juno.com> Subject: Tip for Pressure Cookers I was trying to pressure can some wort recently, but the cooker just wouldn't cooperate. The rubber seal on the lid wasn't sealing, so the pressure wasn't rising. A new seal was the obvious solution, but its a 30 minute drive to any sizable store and they weren't likely to have one anyway. In a rare moment of lucidity, I thought about trying keg lube on the seal. I shut off the burner, removed the seal from the lid, dried it off, and applied a thin coating of the silicone grease. Put it all back together and bingo! Works like a champ now. Jim Layton Howe, TX Return to table of contents
Date: Sat, 11 Nov 2000 12:14:49 -0500 From: Jeff Renner <nerenner at umich.edu> Subject: Re: R/O Water Charlie Preston <cp1811 at yahoo.com> in Mansfield, Ohio asked > I can purchase r/o water at the local supermarket >for .39 a gal. but can anyone help me with the amounts >of salts to use for a Pilsner?_________a pale ale? Check out Glenn Tinseth's Javascript water salts calculator at http://realbeer.com/hops/wcalc_js.html Quick and dirty, I'd suggest one teaspoon of calcium chloride per five gallons, and don't treat the sparge water. That should get you pretty close to where you want to be - enough calcium and no sulfate. On the other hand, the chloride may tend to soften the beer a bit. If you like a crisp, dry pils, it wouldn't hurt to substitute a little gypsum (calcium sulfate) for some of the CaCl2 - just don't overdo it. You could figure out just how much Ca++ this would get you if you like. You'll need maybe 50 ppm. Don't forget that there are water molecules in the CaCl2 - it's probably di-hydro, that is, CaCl2*2(H2O), although I note that Glenn's calculator suggests hexa-hydro, that is, CaCl2*6(H20). The chemists among us can probably help on this. The shops haven't seemed to know for sure which they carry Jeff - -- -=-=-=-=- Jeff Renner in Ann Arbor, Michigan USA, c/o nerenner at umich.edu "One never knows, do one?" Fats Waller, American Musician, 1904-1943 Return to table of contents
Date: Sat, 11 Nov 2000 10:59:58 -0700 From: Ken Schwartz <kenbob at elp.rr.com> Subject: Salts for Pilsner & Pale Ale from RO Water, And a Scale to Weigh Them Here are some "recipes" for the requested water profiles. I used BreWater 3.0 (see my web page) to come up with this. Weigh salts if possible, instead of teaspoon measures. Teaspoon equivalents are approximate and weight may vary. If you're brewing with extract, it's probable that the water used to mash the grains that made the extract had some non-zero ionic content, maybe or maybe not appropriate for the style, so all bets are off as far as "matching" the profile to any particular target. You could take a chance on all or some portion of the mix given in that case. If you're mashing, add a portion of the chalk separately to the mash (add slowly and monitor pH if you can, but you should be OK). Add the rest to the sparged wort. Clacium Chloride can reduce or eliminate the need for chalk in many "recipes" but it sometimes hard to find. I have been buying mine from Hoptech (http://www.hoptech.com , item CMCACL, $2 for 2 oz = 56g). As for weighing, try http://www.edmundscientific.com/Products/DisplayProduct.cfm?productid=777 (item CR36-028). It's a bit pricey for what it is, but I use one and I can say it works nicely. You can resolve down to about 0.05 gram; it has a 4 gram capacity. Seems I've seen them offered elsewhere for less but I can't remember. RECIPES: ======= For 5 gallons RO water: Mosher's Burton-on-Trent: 11.7g Epsom salts (about 2-1/2 tsp) 0.45g Baking Soda (scant 1/8 tsp) 3.97g Chalk (1-1/2 tsp) -- add to mash 1.23g Non-iodoized salt (scant 1/4 tsp) 14.2g gypsum (5-1/2 tsp) Mosher's Pilsner: 0.15g Epsom Salts (.03 tsp! probably just a sprinkle would do) 0.28g Chalk (scant 1/8 tsp) (this small amount should dissolve OK in the water) 0.16g Non-iodized salt (0.03 tsp -- again, just a sprinkle) 0.09g Gypsum (0.04 tsp -- sprinkle) Clearly there is not much happening in Pilsner water, so it is debatable whether you need to do anything at all. If extract brewing, skip salts altogether. If mashing, skip the salt in the strike water, mash in, and check pH. SLOWLY add gypsum or (better) calcium chloride ONLY IF NECESSARY until pH is adjusted. The Calcium in the gypsum or calcium chloride is what lowers the pH. The carbonate in chalk "outweighs" the effect of its calcium and thus has the opposite effect on pH (raises it). - -- ***** Ken Schwartz El Paso, TX Brewing Web Page: http://home.elp.rr.com/brewbeer E-mail: kenbob at elp.rr.com Return to table of contents
Date: Sat, 11 Nov 2000 13:04:28 -0500 From: Jeff Renner <nerenner at umich.edu> Subject: Ring the Bull Forrest Duddles - Fridgeguy in Kalamazoo <fridgeguy at voyager.net>, for once gets to ask for some help instead of giving it: >The proprietor of a local pub has recently seen a reference to an >English pub game called "Ring the Bull" and would like to offer it to >his patrons. He has not been successful in finding enough construction >details and asked if I knew where to ask. This doesn't have details, which I hope someone else can provide, but it's something: >From http://web.ukonline.co.uk/james.masters/TraditionalGames/RingingTheBull.htm Ringing the Bull History This is an indoor game the aim of which is to swing a metal ring which is dangled from the ceiling on a rope, onto a metal hook on the wall. Originally, the hook was a bull's horn. Quite often the hook is embedded in the nose of the head of a bull on the wall. Other variants exist featuring other animals such as stags and pigs. The game is one of the oldest in the country; legend has it that it was brought back by Crusaders from Jerusalem. The story appears to have come about primarily from the most famous pub featuring the game - the venerable "The Trip to Jerusalem" situated in the cliffs underneath Nottingham castle. This pub is an old crusaders tavern dating from 1189 and so the legend certainly is not without merit. The game is so simple that many pubs stage it simply as an informal pastime rather than as a competitive game. A person will make a a number of attempts to ring the bull and then pass the ring to somebody else for a turn. The basic throw is simple a swing in a clockwise direction (for a right handed player) straight onto the ring but advanced players can also ring the bull across themselves in an anti-clockwise direction. Old hands are able to throw with either hand in either direction and will then really impress their spectators by facing away from the hook and swinging in the opposite direction such that upon its return the bull is ringed. For extra difficulty, they might do this while standing next to the target instead of at the usual throwing mark. The ultimate throw is one which circles the room completely twice and then lands squarely on the target. Difficult yes, but not impossible! -=-=-=-=-=-=-=- From http://www.protzonbeer.com/documents/27660-001240.html Bull, The Village, Stanford Dingley, Berkshire. Off A4 & A340 (0118 974 4409) The Bull naturally features the ancient game of Ring the Bull. It's one of the most frustrating games I've ever come across. It's a member of the 'lobbing' group of pub games and is essentially an indoor version of quoits. A ring, replicating the ring in a bull's nose, hangs from a string and has to be lobbed, swung, spun or flipped on to a hook on the wall. You can get extremely bad tempered playing this game, and the Bull fortunately offers soothing pints of Brakspear Bitter, and West Berkshire Skiff and Good Old Boy. Also check http://users.classicfm.net/shakesbeer/INFGAME.HTML Jeff - -- -=-=-=-=- Jeff Renner in Ann Arbor, Michigan USA, c/o nerenner at umich.edu "One never knows, do one?" Fats Waller, American Musician, 1904-1943 Return to table of contents
Date: Sat, 11 Nov 2000 15:27:53 EST From: GASNER at aol.com Subject: Pre-packaged salts Sure, all water is not alike at the start. Suppose you pass your local water through a de-ionizer? A water softener would work too, though not as well as it would not take out bi-carbonate or carbonate. But, I assume that adjusting the pH later would take care of any concern there. ??????? Earl L. Gasner gasner at aol.com Return to table of contents
Date: Sat, 11 Nov 2000 20:33:06 +0000 From: "A. J." <ajdel at mindspring.com> Subject: Salts Charles Preston has the solution to Terry White's problem: use RO or distilled water. Now on to Charly's question. A good approximation to the water of Pisen can be obtained by adding 3.45 mg non iodied table salt, 6.49 calcium chloride dihydrate, 16.13 mg epsom salts 11.37 mg/L chalk and 2.14 mg sodium bicarbonate to each liter of RO water being prepared. It will may be necessary to bubble CO2 through the water to get the chalk to dissolve. A much simpler way of getting suitable water for Pilsner is to mix 1 part tap water with three parts RO water. Assuming that the tap water is nominal US municipal water i.e. hardness around 100, alkalinity 100 or so, sulfate less than 50, chloride less than 50 this should work out fine. If the mineral contents of the tap water are about double what I listed, dilute 6 + 1 instead of 3 + 1. To emulate Burton water for pale ale use 40.18 mg of the table salt, 982 mg gypsum, 1.25 mg calcium chloride, 456.15 mg epsom salts, 164.26 mg chalk and 143.,16 mg sodium bicarbonate in each liter. Carbon dioxide sparging will definitely be required to get the chalk to dissolve. Note that CO2 is how mother nature gets the limestone dissolved in real Burton water and we are emulating mother nature here. This technique give a very close approximation indeed to a published Burton profile. Return to table of contents
Date: Sat, 11 Nov 2000 21:37:06 +0100 From: "Hubert Hanghofer" <hhanghof at netbeer.co.at> Subject: Zn solution - biological stability? Hi all, Alan replied to Graham in HBD#3476: "Seems to me that the best bet is to add a small volume of sterile Zn solution to the wort after cooling and whatever break-removal you normally do. This will eliminate losses of Zn to the grain bed and minimize losses to precipitation during the boil and complexation to the break material." That's a good point, it may explain some of the inconsistencies I've encountered using a ZnCl2 solution. I added it to starters before boiling and to the wort 10 minutes prior to knock out. I've seen ZnCl2 is also added this way in breweries outside Germany (except they use measuring cups and dry ZnCl2). A question to the biologists regarding sterility of that solution: For wort additions I used a 2000 ppm Zn priming-solution: 4.17g ZnCl2 p.A. per Liter deionized water. This concentration was choosen for easy dosage with a syringe: The solution contains 2mg Zn / mL, so I had to add 7.5mL = 15 mg to rise the Zn level of 50L (13.21 US gal) wort by 0.3 ppm. The solution is now 8 month old and still clear. Considering the pH of about 5.5 I'm a bit concerned regarding the biological stability of that solution. I've heard Zn has a bacteriostatic effect. Is that true and will it help to keep the solution in a sanitary condition that is suitable for brewing additions? ...or do I risk botulism ;-);-);-) 0.2um filters would be an option. I don't know the cost of the other option (10ppm ServoMyces added prior to knock out) but sterile 0.2um syringe filters are not cheap either. Allzeit gut Sud! Hubert thinking about zincing in Salzburg, Austria Return to table of contents
Date: Sat, 11 Nov 2000 13:11:02 -0800 (PST) From: "Scott D. Braker-Abene" <skotrat at yahoo.com> Subject: C'ya MidWest! Hello New Hampshire... Hiya, I am packing up and moving out of the windy city to head back east where freakish people like myself belong. Besides... The folks round here cannot figure out the plaid shorts in the middle of the winter... Nor can they understand the late night bagpipe music I play so that my Scotch Ales ferment out better (a happy ferm is a good ferm). I am looking for active brew clubs and quality brew supply places in the seacoast area of New Hampshire. Any good ideas? Thanks for the help... Hey Pat... Keep the Plaid Fight Alive and Well in the Good Ol Midwest for me... C'ya! -Scott Abene ===== Scott Braker-Abene Comark Inc. webmaster at comark.com <mailto:webmaster at comark.com> http://www.comark.com __________________________________________________ Do You Yahoo!? Yahoo! Calendar - Get organized for the holidays! http://calendar.yahoo.com/ Return to table of contents
Date: Sat, 11 Nov 2000 18:11:46 -0500 From: "Stephen Alexander" <steve-alexander at worldnet.att.net> Subject: re: Low gravity/Burp Danny Breidenbach says .... >For really good low gravity brewing, you [...] >set up a brewhouse in the Intl. Space Station >or something. Beer in Space - see the archives for an extended discussion. == Graham says ... >I quote from 'Moral American for Beginners' [..] >"You must treat all things with the utmost seriousness, even if it >doesn't warrant such action. You confuse morality with being occasionally sober & curious with an interest in communicating more interesting than "burp". It may appear different from the outside, but it's always an error to attribute morality to any American activity which could even remotely be ascribed to greed, sloth, fanatic zeal or personal aggrandizement. -S Return to table of contents
Date: Sat, 11 Nov 2000 19:07:36 -0700 From: "Dave Howell" <djhowell at uswest.net> Subject: Thanks for helping ID keg type Thanks to those who helped me ID the keg type I'd asked about. It was indeed a German Slider style (I thought a slider was either a hard breaking ball or a hamburger). The keg was made by Firestone, and holds 15.5 gal, 1/2 bbl. Disassembly for cleaning proved what I suspected (a mess), and now it will be surgically modified to begin life as a mash kettle. It's second-to-last owner before me (the last was a junkyard) was an outfit called Celis Brewing, Inc, in Austin, TX. Just for curiosity's sake (Phil Yates, no feline observations, please) does anyone know any history on this (I assume now defunct) brewer? What they brewed? What happened to them? Thanks again to those who helped. Dave Howell Mesa, AZ. (Very, very far from the center of the brewing universe) Costello: You know I'm a catcher too. Abbott: So they tell me. Costello: I get behind the plate to do some fancy catching, Tomorrow's pitching on my team and a heavy hitter gets up. Now the heavy hitter bunts the ball. When he bunts the ball, me, being a good catcher, I'm gonna throw the guy out at first. So I pick up the ball and throw it to who? Abbott: Now that's the first thing you've said right. Costello: I don't even know what I'm talking about! Return to table of contents
Date: Sat, 11 Nov 2000 21:58:37 EST From: CeolNaFidhil at aol.com Subject: Krupnik? Off brewing topic, (Sort of) There is a Polish liquor that goes by something like "Krupnik" it's a vodka spiced with cinamon & cloves etc. Has anyone ever heard of this stuff before?? Does anyone have a recipe?? If so please post a recipe or feel free to email me. Thanks in advance!! ;o) Return to table of contents
Date: Sat, 11 Nov 2000 23:56:00 -0500 From: "Stephen Alexander" <steve-alexander at worldnet.att.net> Subject: Enzyme Kinetics - part 3 To recap slightly we just provided a hand-waving argument for the shape of the curve relating the rate of enzyme product formation with the concentration of substrate being acted upon: For notation we had written E + A <==> EA ==> E + P -k1-> -k2-> <-kr1- indicating that an enzyme(E) and substrate(A) molecule could form a complex(EA) which was unstable and would either produce product(P) and free enzyme, or else revert to a free enzyme molecule and one of substrate. The rates named are k1, k2 and kr2. << The rate of product formation increases almost linearly with substrate concentration [A] until the amount of free enzyme [E] decreases sufficiently. Then at this high [A] value (to the right) the rate of product formation v0 is limited to a maximal value Vmax. A nice graphic can be found at http://ull.chemistry.uakron.edu/biochem/slide.html$Chap ter=/biochem/06/&Last=59&Slide=11 (note line wrap on URL above) >> Now a more rigorous (and mathematical) description can be launched. - --------- --------- ------- = Effects of Substrate Concentration on rate of Catalysis (cont) In a closed system we can write some obvious equations. The initial amount of enzyme present (assuming none is lost or denatured) is equal to the amount of free enzyme plus the amount of complexed enzyme+substrate so: [E0] = [E] + [EA] The initial amount of substrate equals the remaining substrate plus the amount which is complexed with enzyme, plus the amount of product: [A0] = [A] + [EA] + [P] This last equation is not always literally true. There are cases with different stochiometry, for example enzyme reactions that take 2 molecules of A and yield 3 molecules of P have a different but similar equation. When enzyme is initially introduced to a high concentration of substrate ([A] >> [E]) there is initially no product and no EA complex. Typically in a matter of milliseconds the concentration of complex([EA]) stabilizes at an equilibrium value, where the formation rate k1 is equal to the decomposition rate (kr1 + k2). The reaction continues at this rate for some time until some limiting factor changes the equilibrium. Often the product concentration [P] acts to inhibit the forward reaction (k2) , or to increase the rate of the reverse reaction (kr1). Often the enzyme concentration [E] drops over time as enzymes denature. Since many factors can affect this latter period enzyme analysis often, but not exclusively, focuses on measurements made during the 'linear' period, after the first few milliseconds when equilibrium is established, but long before changes in product or enzyme concentrations can effect the rate. During this linear phase we can define several relationships: 1/ Rate of complex formation is the formation rate constant times the concentrations of enzyme and substrate d[EA]/dt = k1 * [E] * [A] (formation only) 2/ Rate of complex breakdown is the sum of the reverse and forward breakdown rates. -d[EA]/dt = kr1 * [EA] + k2 * [EA] (breakdown only) 3/ Rate of product formation v0 is the complex concentration times conversion rate constant. v0 = d[P]/dt = k2 * [EA] { note: the use of the minus sign in eqn 2/ is misleading. At equilibrium only the amount of complex (EA) is constant so the change in the amount of complex is zero : d[EA(total)]/dt = 0 = (d[EA]/dt formation + d[EA]/dt breakdown I greatly dislike the confusing notation that separates formation & breakdown, but it is common in the literature. It is often written -d[EA]/dt = d[EA]/dt, which means the rate of formation and breakdown are equal in magnitude at equilibrium, and not (tho' trivially true) that the rate change of the total is zero. } 4/ During equilibrium the rate of complex formation equals breakdown rate or (from 1/ & 2/) k1 * [E] * [A] = ( kr1 + k2 ) * [EA] 5/ In order to determine the amount of complex, so that we can solve for the rate of product formation we note that the enzyme concentration [E] is the initial concentration [E0] minus the amount involved in the complex [EA] so: [E] = [E0] - [EA]. 6/ And by substitution (4/ & 5/) we get: k1 * ([E0] - [EA])[A] = (kr1 + k2) * [EA] 7/ solving for [EA] in 6/ we get [EA] = [E0] * [A] / ( (kr1 + k2)/k1 + [A] ) 8/ substituting the rate of product formation (3/ & 7/) we have: v0 = d[P]/dt = k2 * [EA] = k2 * [E0] * [A] / ( (kr1 + k2)/k1 + [A]) This bit of analysis and algebra is precisely what won L.Michaelis and M.L.Menten continuing honors when the first presented the result in 1913. The constant ((kr1 + k2)/k1) is called the Michaelis constant with notation Km. 9/ Km = (kr1 + k2) / k1 So the Michaelis-Menten equation is written: 10/ v0 = k2 * [E0] * [A] / (Km + [A]) which describes the rate of product formation during the equilibrium period. That is enough for now, and a lot to absorb in one post. After you've brushed through the algebra, ponder the fact that the rate of product formation at equilibrium is proportional to the product formation k2, to the initial concentration of enzyme [E0], and to the term ( [A] / ( Km + [A])) Also think about the fact that the Michaelis-Menten constant Km is a concentration !! Understand that the forward rate constant k1 has units like Liters/mole-second, while kr1 and k2 have units of 1/second, so the fact that Km is a concentration makes sense. Keep in mind that the above only applies to the condition of equilibrium of an enzyme with a single substrate. Next time we'll examine some of the implications of this along with the results (w/o the math development) for a two substrate enzyme, like the amylases. -S Return to table of contents
Date: Sun, 12 Nov 2000 01:36:59 EST From: BShotola at aol.com Subject: Lagering under pressure Hello all, I am wondering how to best lager my beer. Let's say I have two identical lagers in my chest cooler: one in a glass secondary fermenter with an airlock, and the other, which immediately following fermentation, has been siphoned into a cornie keg and charged with co2. Will these have the same characteristics when consumed after 4 weeks, assuming the first has been carbonated at the end of this time period, of course. Or does the lagering process suffer when the carbonation is added early? Shed some light, please. Bob Shotola Yamhill, Oregon Return to table of contents
Date: Sun, 12 Nov 2000 00:03:04 -0700 From: "Richard & Laura" <dromedary at worldnet.att.net> Subject: water filter harboring bacteria? I've learned a lot about brewing from reading HBD. As a side-effect, I've also become paranoid about things that weren't a concern before. Like using tap water to make beer. Well, I was feeling pretty smug yesterday, being a government employee with the day off work. I strolled into the Home Despot and bought a GE brand "SmartWater" Refrigerator/Icemaker water filter (Model #GXILQ) for filtering the city water that I've been brewing with since 1993. It cost about $25. I also bought a pair of barbed fittings to splice the filter into the hose that I use to fill the brewkettle. Seemed like a great idea until I searched the HBD archives and read dire warnings about bacteria growing in carbon filters(!) Several posts suggested that "bacteriastatic" filters, containing silver oxide, would not harbor bacteria. I read all the paper work that came with my filter, but found no mention of any "bacteriastatic" properties. GE's web site was uninformative. Then, I found this rather cryptic statement in HBD#1539: "Once a population of nitriting bacteria establishes itself in a new filter, it will also remove the free ammonia that is inevitably present from NH2Cl addition." Huh? So--should I or should I not use the filter? And, if I use it, is there preferable way to store it between uses? I have a quick-disconnect on my kitchen faucet, so the hose and filter will stay with the rest of my brewing stuff in a cabinet between uses. Richard Dulany El Paso, TX Return to table of contents
Date: Mon, 13 Nov 2000 09:08:15 +1100 From: "Grant Stott" <gstott at primus.com.au> Subject: Strange yeast formations G'day all, Some time ago there was discussion either in rec.crafts.brewing or HBD about strange yeast formations on the inside of the bottles on some batches. I remember reading about it at the time & thinking that is really weird, must be some sort of strange northern hemisphere type thing. Anyway this weekend I was shifting my latest batch of Kolsch from the heated carbonation box to the fridge when I noticed that on one side of the bottles there was a large dark patch. So I look closer & find that it appears that some of the yeast is clinging to one side of the bottle & that it seems to form fine vertical lines. This appears to have occurred in at least a third of the bottles & these bottles have been kept vertical since bottling. I am not concerned as the batch turned out excellent, even SWMBO gave it the thumbs up (its the only style she likes). So can anyone recall if consensus was reached on what causes this phenomenon. Is it static electricity, Magnetic north, one side being warmer, a shift in the space time continuum? What a grouse hobby even on a batch that turns out otherwise text book there are things to be learnt. Grant. Australia. Return to table of contents
Date: Sat, 11 Nov 2000 14:48:56 +0100 From: "Dr. Pivo" <dp at pivo.w.se> Subject: Some highly personal and unverified thoughts on pitching temperatures for lager yeasts. This subject has just flown by here, with inputs of varying levels of interest (We were even graced with the "pitching rate mantra" once again, though I'm quite sure it had nothing to do with the subject at hand.... at least it fullfilled that great HBD tradition.... confuse the hell out of the neophytes, and bore the socks off of the informed.) This is a subject I have thought about a fair ammount, because of a long collection of "casual observations", which I cannot explain at all. I would like to stress that this is real "category one" stuff, that is, I've noticed this for a long time, but have not done any stringent testing to see if my observations are correct. I say this as a leading word of warning, as I may just be repeating that most famous of all human habits -- paying real close attention to every thing that fits in with what I already believe, and ignoring everything that contradicts it. Anyhow, this is my "take" on lager pitching temperatures, and I have no logical explanation for it.... One should start by stating the "ground rules". Everywhere I have ever heard the subject discussed by knowledgable people, say "between 8 and 12 C in the primary". I will leave out those who lay outside this (and some very famous beers indeed in fact do) but take this as sort of a "basic rule" for lagers. the upper limit of 12 being the most interesting here. Now I would like to add the observation, that I have spent a perverse ammount of time in breweries, particularly lager ones, and when I am not asking pesky questions, I am usually walking around with my right index finger planted firmly in it's ipsilateral nostril (it fits so nicely there, I figure it was meant to be so)... staring at things in the brewing world. I have MANY times, seen primaries in every condition, that is, old tiled open fermenters to modern CKT's where the temp may be 13C, and even brushing up against 14. When I see this, I do NOT go running to the brewmaster and say "It's at 13! It's not supposed to be over 12! you've even said so, yourself!" No, what I do is try and read the date code on the tank or ask someone when it was pitched, and it is always "fairly early, like between "white" and "high" krauzen. My take has been that the yeast are generating heat faster than they can get rid of it. Since I consider the brewmasters there to be good craftsmen (otherwise I wouldn't be there picking their brains) I don't think this is shoddiness on their part, but rather as all good craftsmen, they must: 1) know all the "rules" of their art, and 2) know when, and by how much, and how often they can break them without compromising their work. Now there's One point, here comes the next: This will require that we state a defined difference in taste between "ales" and "lagers". I suppose we could define this by individual chemical composition, or even "families" of chemicals, but let's not. Let's just leave it at, anyone who has been around beer a lot can taste the difference, and a lager that is fermented too warm will taste "ale-like". If you can buy that premise, then here is my next observation: If you take a typical situation like: a lazy lout like myself is bored with chilling and so pitches the whole lot at 18C and then puts it in a 10C ambient place. It will eventually end up at 10 C, but when? Now there was some very elegant and clever observations made by a guy named John Thomasson from a place where they habitually breed or kill American Presidents. He simply watched gravity and temperature over time. What he saw, was that in the above situation, more than half of the fermentables were used up at "illegal" temperatures. Now here's the crusher... the above theoretical brew will be far more lager like in flavour (and in fact there is no problem with it) that one which is started, and held the whole way through at 13C. Now how should one understand that? beats me. I've got a long list of guesses that have to do with "cascades of Redox" that would make the whole picture not a bit clearer than if I didn't mention it at all, but here's the rub, and it is my highly personal and perhaps incorrect thought... It seems MORE important that you get to and finish the primary at "legal lagering temperatures", than where you start at..... it is sort of like the "lagering process" of smoothing out flavours begins in the primary, and if you DON'T get there during primary, you will have a beer with ale-like flavour, that all the cold lagering in the world will not repair. Here's another odd tidbit.... I always split my ferments in order to try different stuff. Quite often when I do the "lazy chill" thing I'll have ferments where one is twice as large as the other. Now the smaller one will get to ambient faster that the big one (I promise), and then comes the big question..... which one is better? The answer is "neither". They are always discernible, even if in very subtle manners from each other, but I have never had one consistantly be the one I prefer (Or I'd always do it thus). Just too many factors here. So, this is just one of those "brewing paradoxes" that certainly seems repeatable to me, but I can not for the life of me explain it. Now if some brave soul like John Thomasson would do some actual testing and measuring, instead of theorising, I'll be the first in line to hear the results. Dr. Pivo Return to table of contents
Date: Sun, 12 Nov 2000 21:33:46 -0500 (EST) From: Some Guy <pbabcock at hbd.org> Subject: RE: Tip for Pressure Cookers Greetings, Beerlings! Take me to your lager... james r layton writes: > anyway. In a rare moment of lucidity, I thought about trying keg > lube on the seal. I shut off the burner, removed the seal from the > lid, dried it off, and applied a thin coating of the silicone grease. > Put it all back together and bingo! Works like a champ now. Most pressure cooker manufacturers recommend putting a thin film of vegetable oil on the seal at each use. One case where actually reading the directions would have saved a tad bit of concern :-) - -- - See ya! Pat Babcock in SE Michigan pbabcock at hbd.org Home Brew Digest Janitor janitor@hbd.org HBD Web Site http://hbd.org The Home Brew Page http://hbd.org/pbabcock "The monster's back, isn't it?" - Kim Babcock after I emerged from my yeast lab Saturday Return to table of contents
[Prev HBD] [Index] [Next HBD] [Back]
HTML-ized on 11/13/00, by HBD2HTML version 1.2 by K.F.L.
webmaster at hbd.org, KFL, 10/9/96