HOMEBREW Digest #3521 Thu 04 January 2001

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  The Mystery is Solved! ("Brian Lundeen")
  Re: Degree Confluence Project (David Lamotte)
  Re: Microwaves ("Rick Wood")
  Different carbonation levels in kegs & bottles (Tom smit)
  A Brew Day With Doc Pivo ("Phil & Jill Yates")
  Mashing a 100% wheat beer (Joel Plutchak)
  Re: Degree Confluence Project (Jeff Renner)
  Airstones (LaBorde, Ronald)
  Microwave RIMS (LaBorde, Ronald)
  Question about Lagers/Lagering (cmmundt)
  Re: Yeasties (Keith Brown)
  Boston Homebrew Competition/MCAB IV Qualifying Event (Timothy Holland - Hardware Program Manager)
  Yeast Temperature Tolerance ("Darryl Newbury")
  RE: kettle spigot/hop pellets ("Dan")
  Confluence Project ("Eric Ahrendt")
  Alpha/Beta Acids in Hops ("A. J.")

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---------------------------------------------------------------------- Date: Tue, 2 Jan 2001 12:54:22 -0600 From: "Brian Lundeen" <blundeen at rrc.mb.ca> Subject: The Mystery is Solved! Well, I heard from my network administrators this morning, and discovered why I haven't been receiving my Digest since the big switch. It had nothing to do with propogating DNS's or anything else that would send technogeeks into nose-running fits of uncontrollable excitement. No, our network people are simply blocking you. It seems you have joined an Evil Empire, Pat. Somebody, somewhere in the 63.xxx.xxx.xxx class of addresses has been spamming our email, so in typically Dilbertesque style, our net people have sledge-hammered the 2 million or so domains that fall into this group. I suspect these network people would also do well in equine veterinary medicine (Hi, my horse has ... BLAM!) but I digress. Supposedly, we are switching to a revised mail system in the next couple of weeks (this has been promised for over a year now, so I'm not holding my breath), which should allow the blockades to be dismantled, and the HBD can resume its rightful place in my inbox. I mention this as encouragement to others out there that may be suffering at the hands of NetTyrants. We may not be able to overthrow them, but we can at least offer each other hugs of solace (Australians: substitute hearty mocking laughter) at our oppression. My apologies to the Janitors, I didst verily accuse them falsely. Cheers, Brian Return to table of contents
Date: Wed, 03 Jan 2001 17:04:24 +1100 From: David Lamotte <lamotted at ozemail.com.au> Subject: Re: Degree Confluence Project Our good mate Jeff Renner recently posted on the opportunity to make pioneer visits to intersections of integer latitude and longitude lines for the Degree Confluence Project. Now in my case (Cessnock, NSW Australia) I got all excited as it sounded like I could pop out during lunch and become a hero. But when I looked it up on our mapping system, pioneer was the right term for it. It is so hilly, timbered and remote, that you can almost hear the banjo's playing. The only hope would be to drop in via helicopter. Might have a talk to our Bush Fire guys - maybe they would like to do a 'training' run one day. Might have to bribe them with BEER (note the sudden swerve back on topic). Hope that I didn't push anyone's buttons..... David Working in Cessnock, New South Wales, Australia Return to table of contents
Date: Wed, 3 Jan 2001 17:15:29 +1000 From: "Rick Wood" <thewoods at netpci.com> Subject: Re: Microwaves Hello All, I should like to thank all who replied regarding the microwave rims. Especially Stephen Alexander, who as usual (and in his constructive manner) discussed the idea seriously. Stephen is not "in love with microwave heating", but never-the-less experimented with it - a true scientific attitude. I too await any Enzymology posts Stephen! Hope I haven't damaged your reputation by calling you cojstructive, scientific and requesting more enzymology! I am accumulating RIMS materials for my implementation. I have a bad habit of thinking too much regarding projects and not doing projects. I am 54 and perhaps it is too late to change my ways! Most criticisms of RIMS has to do with expense and the inability to do temperature boosts rapidly enough. Perhaps a hybrid system with the traditional in line heating element for temperature maintainanence and a microwave coil along with the heating element for temperature boosts? My understanding is that the heating element alone is almost enough to do boosts. With a little help from something else - microwaves - perhaps would solve the problem. Just as easy I suppose would be a second heater. Has anyone out there ever used two inline heaters in a RIMS implementation? I would envision the second heater being controlled with a PID and the first, the boost heater, being controlled with a switch. A series system would only require one pump. Perhaps there are advantages to run two heaters in parallel? This for a 10 - 12 gallon batch. Regards, Rick Wood "brewing on Guam" > Date: Tue, 2 Jan 2001 00:22:16 -0500 > From: "Stephen Alexander" <steve-alexander at worldnet.att.net> > Subject: re: microwave RIMS? > Return to table of contents
Date: Wed, 03 Jan 2001 18:56:34 +0000 From: Tom smit <tom at lunica-data.com.au> Subject: Different carbonation levels in kegs & bottles Hi, I made a rather nice bitter recently and bottled a bit over half and put 10l into two 5l little kegs. The last bottle was finished last weekend-it had a nice low carbonation and a nice head, though not as creamy and persistent as I had hoped for. Last night I tapped the first of the two little kegs and got a gusher of foam. The only difference in treatment of the bottles and kegs was that the kegs spent a week or two longer in my 'cellar' (at20C) than the last bottles did. What caused this huge difference in carbonation? An extra week at higher than 'fridge temperature? The larger volume of ale in the keg? I have 20l Russian Imperial Stout (a partial mash version of the recipe in G Wheeler's book) sitting in four more of the little kegs since 25/11/00. Will they also be gushers? Should I tranfer them to another container that can be vented? They have a long time to mature before bottling! All six kegs are now sitting in my second brewfridge. TIA Tom Smit Little horses brewery At 34deg 52' S, 138deg, 30' E, can someone pls figure out for me my Rennerian coordinates? (I'm too busy draining my little keg before it explodes) Return to table of contents
Date: Wed, 03 Jan 2001 07:17:37 -0500 From: nap_aca_bh <nap_aca_bh at nwoca.org> Subject: Jeffrey Luck writes about Wyeast 1056: >My first forray into liquid yeast has left a bad taste in my mouth, both literally and figuratively.< I have had some excellent brews with 1056, but by the same token I also have had batches that exhibited the sour taste that Jeff describes. Last summer I split a 5 gal. batch of blond ale wort into two fermenters and pitched 1056 into the first and Danstar Nottingham dry into the second. Temp was 70 degrees. Nottingham finished sooner and clearner, while the 1056 had a slower fermentation and finished with that sour aftertaste. The Nottingham half was quickly consumed ... the most of the 1056 batch went down the drain during my New Years clean-up. Has anyone noticed variations in 1056, or can anyone explain wort deficiencies that could account for the 1056 outcome? As I said before, I've had some excellent brews with 1056, but the variation of results has left me a little gunshy. Thanks, Bob Return to table of contents
Date: Thu, 4 Jan 2001 00:38:54 +1100 From: "Phil & Jill Yates" <yates at acenet.com.au> Subject: A Brew Day With Doc Pivo I did promise to report on the combined efforts of Doc Pivo and myself regarding our brew day together. Firstly I have to say the "Doc Pivo" I am talking about is Jeff Irvine from Sweden. There seems to be some thought in here that the identity has been passed on to someone else. I can assure you that Jeff is still alive and kicking. So much so that it is nearly impossible to put him to bed! I have a theory that Scandinavians like to stay up all night because at this time of year there is virtually no daylight back home and they don't have to wake up in the morning. Anyway, we set about making a Czech pilsner which is of special interest to Jeff. He has spent a lot of time exploring the style. We used a lager malt along with a small portion of munich malt and flaked barley. Jeff had brought along with him a bag of Czech saaz pellets which we used in conjunction with my New Zealand saaz flowers. Jeff, wearing his brewing helmet made for him by my little girl Phoebe (an upside down ice cream bucket with rooster tails) demanded a three hour boil. A three hour boil? Well how could I argue with a bloke with an ice cream bucket on his head? Jeff says a lot of things happen in a three hour boil and the end result is worth it. I guess we'll find out next month. We split the resulting wort into two fermenters (my usual practise) and added a Saflager dry yeast starter to one. Into the other we pitched my Ayinger liquid yeast. The whole exercise was a lot of fun and next month Jeff will be back for the opening day (I guess more sleepless nights will ensure). I'm hoping to get together a few more Aussie brewers as I am sure they would be interested to meet Jeff (and hopefully they can stay up all night with him so I can sneak off to bed with my turtle - sorry, that's another story). It was interesting to share a brew day with someone from the far north and several times I found Jeff leaning oddly over the sink. I thought he was being sick but he was just watching water go down the plug hole. "Bloody amazing!" he muttered, "It's going down the wrong way!" A report on results will follow next month. Just on a final note, several folk have asked for more info on the rice lager. I'll be on holidays for the next ten days but promise to explain the mysteries of this beer when I get back. Not that there are any mysteries, but I will tell you what I know. Jeff Renner is really the expert on cereal mashes, and what I know I learnt from him. Cheers Philistine (Well done Steve - Even Doc Pivo thought so) Return to table of contents
Date: Wed, 3 Jan 2001 08:54:00 -0500 From: "AYOTTE, ROGER C" <RCAYOT at solutia.com> Subject: 1056 AND SOUR TASTE Recently, "Jeffry D Luck" <Jeffry.D.Luck at aexp.com> commplained about the poor results he obtained with Wyeast 1056: "The only problem was that my ferment temperature was in the 70F to 75F degree range..... This beer had a sour aftertaste that completely ruined the batch.... my temp was too high. Finally, I tried a ferment at 64F and things worked out. The aftertaste was simply a flavor addition to the beer, not the overwhelming sourness of before. But I've found myself that even with the toned down flavor, I still can't stand that 1056 zing." Jeff, I suggest that your real problem is infection. Wyeast 1056 does not produce sour taste at 70-74F! The reason the cooler temperatures improve your beer is that the particular bacteria or wild yeast that has infected your beer is less tolerant of the low temperatures than your pitched yeast. The reason that the dry yeast works for you is probably that pitching dry yeast when properly re-hydrated, will ferment very fast and keep the "souring" to a minimum. My suggestion is that you thoroughly examine every step of your brewing process and try to find where the infection is coming from! Good luck, I hope you ultimately get beer that tastes good, not just "a toned down after taste" You should be able to get VERY clean and reproducible results fermenting with 1056 or any other quality yeast (yes that includes dry yeast!) even at 70-74F! Roger Return to table of contents
Date: Wed, 3 Jan 2001 09:33:24 -0600 (CST) From: Joel Plutchak <plutchak at ncsa.uiuc.edu> Subject: Mashing a 100% wheat beer I had the good fortune to sample a wheatwine brewed at Flossmoor Station brewpub (Flossmoor, IL USA)-- both the straight stuff and some that had been aged in wood-- and it got me thinking I'd like to brew a strong 100% wheat ale. I do have some questions, though. I checked a lot analysis for the wheat malt I have (Schreier White), and from my inexperienced reading of the specs it looks like although it's a bit low on Alpha Amylase it should be able to convert itself, and perhaps not even need a protein rest. However, this runs counter to what I understood to be the case when dealing with wheat malt, and also with the suggestion by Schreier that you can use the grain as up to 60% (but apparently not more) of the grist. Here are some of the pertinent specs: Lot # 286070: SMC Wheat Alpha Amylase: 19.1 Diastic Power: 110.0 Proteins (Soluble): 3.65 Proteins (Total): 9.79 Proteins (S/T): 37.20 Anybody care to comment on conversion, mash regimen, etc? Specific things like whether a longer rest in the AA-favoring temperature range woould be a good idea, if a protein rest would be a good idea, etc. Also FWIW, I have a bunch of rice hulls to help out with the lautering. Anybody have an idea what the recommended proportion and procedure for using then is? - -- Joel Plutchak "Alcohol is not a magic potion. It doesn't make you plutchak at uiuc.edu look good, appear cool, or feel courageous. It simply robs you of your mind." - Neoprohibitionism from MADD Return to table of contents
Date: Wed, 3 Jan 2001 10:51:18 -0500 From: Jeff Renner <nerenner at umich.edu> Subject: Re: Degree Confluence Project David Lamotte <lamotted at ozemail.com.au> in Cessnock, New South Wales, Australia chickens out going for a lunchtime stroll to his nearest confluence point: >It is so hilly, timbered and remote, that you can almost hear the >banjo's playing. The only hope would be to drop in via helicopter. >Might have a talk to our Bush Fire guys - maybe they would like to do a >'training' run one day. Might have to bribe them with BEER (note the >sudden swerve back on topic). I guess that would be 33S 151E. That does look to be in the middle of nowhere. How about just heading north on Hwy 15 ninety miles to Scone. It looks like 32S 151E is only about seven miles off the road http://www.mapquest.com/cgi-bin/ia_free?lat=-320000&lng=1510000&level=6 Of course, I have no idea what the country is like there. But what an adventure! 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: Wed, 3 Jan 2001 10:09:13 -0600 From: rlabor at lsuhsc.edu (LaBorde, Ronald) Subject: Airstones Huh?? The monster ate some of my post - here it is in full (I hope!) I have been using my racking cane, yes, including the end cap! It makes quite a stir. I connect the pump through that small aquarium line to the output end of a 5/8 or so ID syringe. Then after stuffing a cotton ball or two inside the syringe, I place a small rubber stopper over the curved end of my sterilized (oops, sanitized) racking cane and this goes into the open Ron La Borde Ronald La Borde - Metairie, Louisiana - rlabor at lsuhsc.edu http://hbd.org/rlaborde Return to table of contents
Date: Wed, 3 Jan 2001 10:10:34 -0600 From: rlabor at lsuhsc.edu (LaBorde, Ronald) Subject: Microwave RIMS Whew, it got late, and I just had to get some sleep last night. So here it is today. The real cheap and simple microwave ovens only have on and off with a timer for duration. The better or newer ovens like we have here at work have a timer with settable power levels. It is still full on or full off, but when you dial less power, the magnetron power goes on/off in timed intervals. This whole timer could be replaced or modified to output your timed intervals. The magnetron has a filament, so I am guessing that a separate filament transformer must exist to keep the filament heated at all times when the oven is on. With the simple oven, if you tried to reduce power or voltage, the filament would also cool and this probably would not be good for the magnetron. The power to the magnetron is probably turned on/off through some solid state device that you could trigger with your controller. I would think a Basic Stamp would work quite well, provided you programmed it to output your timed delays and also used it to read a thermistor or two for temperature measurements. I have very limited experience involving shielding of microwaves, but if you could measure or find someone to design the exit ports for the vinyl tubing that had no microwave leakage, you would have a practical microwave RIMS. Of course, you will and should run into a wall of advice and warnings about the dangers of messing around with microwaves. Good luck. Ron La Borde Ronald La Borde - Metairie, Louisiana - rlabor at lsuhsc.edu http://hbd.org/rlaborde Return to table of contents
Date: Wed, 3 Jan 2001 11:56:39 -0500 From: cmmundt at AircraftBraking.com Subject: Question about Lagers/Lagering Hello all, A fellow brewer and I were comparing notes about our lagering procedures. What he does is to rack into a secondary after fermentation is complete and add a clarifying agent, PolyClar. He bottles after 5-7 days, when the beer is clear, and then lets the bottles set for 1-2 months. What I did was to rack into the secondary after fermentation and I am now letting it set for 2 months. I have not added any clarifying agents because I understand that part of lagering at the cold temperatures is to precipitate out the proteins and so forth. His question was: what is the advantage of lagering in a secondary versus lagering in a bottle. Being new to lagers, 3 batches in 2 years, I could not give a good answer. This is where I was hoping to tap into the collective knowledge of the lager brewers, even a rice lager brewer. I currently have two 5 gallon (19 litres) batches lagering. A German Pilsner and what I hope turns out to be a Dortmund style. I was thinking that the yeast in the beer will not be very active for priming when I bottle after sitting for 2 months in 30 F (-1 C) temperatures. Should I add new yeast for priming, and if so, will using a dry yeast cause any off flavors, I used liquid yeasts to make the beer. I was planning on using Saflager S-23 as the priming yeast. Good brewing, Chad Mundt cmmundt at aircraftbraking.com Return to table of contents
Date: Wed, 03 Jan 2001 12:13:05 +0000 From: Keith Brown <bahalana at wt.net> Subject: Re: Yeasties Jeffry Luck wrote: *** I figured to start with 1056, since the general consensus is that it's easy and ferments clean. The only problem was that my ferment temperature was in the 70F to 75F degree range. Trust me, at this temperature, 1056 doesn't ferment clean. This beer had a sour aftertaste that completely ruined the batch. Down the drain. I tried two seperate smack-packs, and different procedures with the same results before I figured out that my temp was too high. Finally, I tried a ferment at 64F and things worked out. The aftertaste was simply a flavor addition to the beer, not the overwhelming sourness of before. But I've found myself that even with the toned down flavor, I still can't stand that 1056 zing. But still, people sing the praises of liquid yeasts. Am I missing something? Is there a liquid yeast that really ferments clean? All the web sites I've seen that compare yeasts simply list krausening type and attenuation - -- is there a site that says something like "1056 - adds a slight citrusy zing to the aftertaste" *** Search the web for "Yeast FAQ". It's pretty old now, but still might have what you're looking for. It is my understanding that liquid yeasts are preferred over dry yeasts mainly because of purity...dry yeasts unavoidably contain a small percentage of wild yeasts. Use what suits you...I just used 1056 in a Sierra Nevada Pale Ale clone and it turned out spectacular...hard to tell from the bottled stuff. And it isn't the yeasts fault that you fermented at the wrong temperature now is it? - -- Keith Brown | I am a professional Air Traffic Controller -- bahalana at wt.net | There are hours when I may be overpaid, web.wt.net/~bahalana | but there are seconds when you can't pay me enough. Return to table of contents
Date: Wed, 3 Jan 2001 14:11:13 -0500 (EST) From: Timothy Holland - Hardware Program Manager <tholland at tunnel.East.Sun.COM> Subject: Boston Homebrew Competition/MCAB IV Qualifying Event Dear Fellow Beer Enthusiast!, The Boston Wort Processors are pleased to formally announce the Seventh Annual BOSTON HOMEBREW COMPETITION to be held on February 10, 2001 in Boston Mass! This competition is run by the Boston Wort Processors and is a BJCP Registered Event. The competition will be held at the Northeast Brewing Company in Allston, MA. This competition will again be the northeast region Qualifying Event for the 4th year of the Masters Championship of Amateur Brewing (MCAB) Competition!! The Wort website below lists the qualifying styles and links for MCAB IV. This competition is also the 2nd in the 2001 New England Homebrewer of the Year (NEHBOTY) series. ALL BJCP STYLES WILL BE JUDGED INCLUDING MEADS AND CIDERS! Entry deadline has been set as Friday February 2, 2001 and the entry fee is $5.00 for each entry. We will also be needing judge and steward support so please come and help us out if you can! All of the information anyone needs to enter the competition or to judge or steward in the competition can be found at: http://www.wort.org/bhc.html including entry forms, bottle labels, judge registration forms, drop-off and mail-to info, etc. We encourage everyone who is interested in this competition to obtain information through the website as information will be continually updated there. Feel free to send me email with questions or call at 781-442-2022. Spread the word and we look forward to judging your entries!! Cheers and Happy Brewing!! Tim Holland Organizer for the 2001 Boston Homebrew Competition (BHC7) tim.holland at east.sun.com 781-442-2022 (w), 508-835-2686 (h) Surf to http://www.wort.org/bhc.html for all details!! Return to table of contents
Date: Wed, 03 Jan 2001 14:18:56 -0500 From: "Darryl Newbury" <darryl at sagedesign.com> Subject: Yeast Temperature Tolerance The temperature of the brewing area seems in my new house, seems to hover around 16C/61F during the winter months. I brewed yesterday with Whitelabs East Coast Ale which has an optimum temperture range of 68-73F, will I have problems getting it to ferment at that temperature? Also can people recommend yeasts that ferment well at that temperature? The only two that come to mind at this time are Danstar Nottingham and California Lager strains such as WLP810 or the Wyeast equivilant. Does the Wyeast Scottish strain ferment at that temperature, Whitelab's apparently doesnt. Will bavarian lager yeast ferment at that warm of a temperature or should I stick with either the Nottingham or California Lager strains? Any information would be appreciated. Cheers Darryl Newbury Toronto, Ontario Return to table of contents
Date: Wed, 3 Jan 2001 18:48:25 -0500 From: "Dan" <knurdami at hotmail.com> Subject: RE: kettle spigot/hop pellets Kevin writes: > I've been thinking about adding a drain to my boiling kettle, but in > searching the archives, the posts I found said this works only with > leaf hops. No pellets, since the screen will be clogged. Is anyone > out there using a kettle drain who brews with only pellets? What > arrangement works? A screen such as an easymasher? Along the sides > of the kettle? A full false bottom? Kevin, I only use pellets and have no problem at all keeping them in the kettle along with the trub. I "whirlpool" the wort after the boil and drain through a 1" ball valve. After the boil is finished, I allow it to rest for a few minutes to stop the churning due to convection. Then simply stir the wort in a circular motion until it is really moving. After this stops spinning (another few minutes) I can drain the kettle through a counter-flow chiller and the hop-trub mixture stays in the middle of the kettle. I have done this for several years and had success with my old 1/2BBL kettle and my new larger kettle. The larger kettle has a wider diameter base which helps but the 1/2BBL had that shallow concave bottom which also helped. I have a picture of what the trub pile looks like after I am almost done draining. As the level falls, the trub pile will start to flatten out and migrate toward the sides a bit more (as in this picture) but you can clearly see that with only a gallon or so left in the kettle, the trub pile sits harmlessly in the middle. http://hbd.org/klob/BigBrew2000/P5060021.jpg BTW, this picture was taken on Big Brew 2000 and I was using the official recipe of Nearly Nirvana Ale which had a healthy dose of hops. Dan Return to table of contents
Date: Wed, 3 Jan 2001 19:16:52 -0500 From: "Eric Ahrendt" <rock67 at peoplepc.com> Subject: Confluence Project In HBD #3520 Jeff R. writes: "On another (off topic) subject that I recently brought up on HBD, you have a opportunity to mkae pioneer visits to intersections of integer latitude and longitude lines for the Degree Confluence Project http://confluence.org/. There have been no visits posted for any of Japan, and 37N, 138E is just a few miles north of you between the villages of Nou and Arai." After the original post I checked out my neck of the woods - Ohioans are an industial bunch. Only one out of ten left and that's way down in the south east. I'll hit it this summer on a motorcycle trip if it's still open. Apparently Michiganians and Ontarians are slackers. Michigan has several open and in Ontario only one out of approximately 150 have been tagged. There's one south of Windsor (probably the southernmost point of Canada, excepting Pelee Point/Pelee Island) that's practically on the beach. I might get that one by boat this summer. Brewing conditions on the south shore of Lake Erie: 10 degrees F outside with a temperature gradient across the basement allowing all kinds of flexibility, electricity cheap as ever thanks to heavy dependance on coal (sorry about the acid rain, Canada), propane bulk delivered for $1.70/gallon. Eric Ahrendt Brewing in Fremont, OH 43420 Return to table of contents
Date: Thu, 04 Jan 2001 02:31:32 +0000 From: "A. J." <ajdel at mindspring.com> Subject: Alpha/Beta Acids in Hops As a couple of people have requested it, here's the method for determination of alpha and beta acids in hops by spectrophotometry as promulgated by the ASBC in their MOA Hops-6. Required Reagents 1. Toluene: Reagent or spectrophotometric grade 2. Methanol: Reagent or spectrophotometric grade (A (1 cm) < 0.06 at 275 nm) 3. 6N Sodium hydroxide solution 4. Alkaline methanol. Add 0.2 mL 6N NaOH to 100 mL methanol. Prepare daily. Required Equipment 1. 250 mL extraction bottle or equivalent (the thick necked 250 mL volumetric flasks with 24/40 glass stoppered neck from Lab Glass are suitable). 2. Mechanical shaker (my interpretation of the words in this and other MOAs has led me to believe that they favor a Burrell "Wrist Action" shaker but I could be wrong about this). 3. Centrifuge 4. Pipets (1, 2, 3, 4, 5 mL) 5. Mixing cylinders or volumetric flasks (100 mL, 25 mL) 6. UV capable spectrophotometer 7. Quartz cuvets Place 5.000 + 0.001 grams of fresly ground hops in extraction bottle Add 100 mL toluene, stopper tightly and shake vigorously for 30 minutes (this can be done manually but it's not much fun). At the conclusion of shaking allow the solids to settle or centrifuge at 2000 rpm for 5 minutes. Don't allow the extract to sit for more than 1 hour. Note: you can use 2.500 grams of hops and 50 mL toluene if desired. Dilute 5 mL aliquot of the toluene extract to 100 mL with methanol. Call this Dilution A. Dilute 2 mL of this to 25 mL with the alkaline methanol solution. Call this dilution B. Check absorbtions at 325 and 355 nm. If they do not fall within the accurate part of the instrument's range, repeat Dilution B using an aliquot of Dilution A of volume greater or less than 2 mL which results in a Dilution B whose absorbtions do. Make readings immediately after performing Dilution B. Make a blank by diluting 5 mL toluene in the same sequence as dilutions A and B. Measure the absorbtion of Dilution B at 355, 325 and 275 nm against this blank. Readings should be made immediately after Dilution B and should be performed as quickly as possible in order to avoid decomposition of absorbing substances by UV light. Calculate dilution factor d d = (mL of Dil. A)*(mL of Dil B) / [ 500*(mL extract)*(mL aliquot Dil A)] for example using a 2 mL aliquot of dilution A d = (100)*(25)/ (500*5*2) = 0.5 alpha acids % = d*(-51.56*A355 + 73.79*A325 - 19.07*A275) beta acids % = d*(55.57*A355 - 47.59*A325 + 5.10*A275) A355 = absorbtion per cm at 355 nm A325 = absorbtion per cm at 325 nm A275 = absorbtiob per cm at 275 nm Return to table of contents
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