HOMEBREW Digest #4332 Tue 26 August 2003

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  potassium meta bisulfites (larry.suarez)
  RE: Dr. Cone Q&A (eIS) - Eastman" <stjones at eastman.com>
  Bottle conditioning lagers ("Fred Scheer")
  yeast pitching/ MHing (Marc Sedam)
  Electrical Element Wattage Density ("Dan Listermann")
  re: you've got mail (Rama Roberts)
  CO2 Safety (again) (Calvin Perilloux)
  Oxygen ("Ronald La Borde")
  O! O, nO! It's nOt O2! (Pat Babcock)
  CO2 effects ("Pete Calinski")
  Oxygen Toxicity ("John Adsit")
  Bubbles, Tiny (and big) Bubbles ("Dave Burley")
  Toronto Tips (Bob Hall)
  240V vs 120V... ("Mike Sharp")
  Dr.Cone Responds-Follow Up Questions- Steve Alexander ("Rob Moline")
  Dr. Cone Responds-Top 5-David Sweeney ("Rob Moline")

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * The HBD Logo Store is now open! * * http://www.hbd.org/store.html * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Beer is our obsession and we're late for therapy! * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * IN PROGRESS! * * * * * * * * * Dr. Clayton Cone Fortnight of Yeast * * 8/11/03 - 8/22/03 Yeast Questions Answered * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 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. 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 or read the HBD FAQ at http://hbd.org. JANITOR on duty: Pat Babcock (janitor@hbd.org)
---------------------------------------------------------------------- Date: Mon, 25 Aug 2003 07:52:53 -0400 From: larry.suarez at gm.com Subject: potassium meta bisulfites Does anybody know how to adjust the sulfites levels in wine just before bottling? Return to table of contents
Date: Mon, 25 Aug 2003 08:39:26 -0400 From: "Jones, Steve (eIS) - Eastman" <stjones at eastman.com> Subject: RE: Dr. Cone Q&A David Houseman makes a good suggestion to create an archive of the Dr. Cone Q&As from this year's session. I will be compiling all the Q&As from this session for my own use anyway, and have a club web site available (on the HBD server), so I'd be happy to make them available to anyone for downloading. Steve Jones, Johnson City, TN State of Franklin Homebrewers (http://hbd.org/franklin) [421.8 mi, 168.5 deg] AR Return to table of contents
Date: Mon, 25 Aug 2003 08:40:24 -0400 From: "Fred Scheer" <fhopheads at msn.com> Subject: Bottle conditioning lagers After my HB lagers endfermented, and lagered for ~ 4 weeks, I start a new HB lager. At the same day, I take the amount I want to bottle conditioning out of lagering and let the temperature raise to ~ 50*F. After the second brew reaches high krausen (usual the 3th day), I take ~ 1 liter of that wort and ad to the 5 gal I want to bottle. I had no problems in the past with that procedure. Thanks, Fred Scheer Return to table of contents
Date: Mon, 25 Aug 2003 08:55:45 -0400 From: Marc Sedam <marc_sedam at unc.edu> Subject: yeast pitching/ MHing On mash hopping... Thanks to Fred Scheer for his data point on mash hopping. Fortunately, since I'm trying to build some kind of model to show why it might work, Fred's observation fits...maybe. Fred, do you have any recollection of the water chemistry? I use mash hops not for bittering, but for flavor and aroma. My all mash-hopped pilsner is a big favorite of my friends, mostly for the hop flavor. One other interesting data point from the mash hop archives. I recently took a vacation to Pacific City, OR and stopped by the Pelican Pub and Brewery. If your idea of a good time is staying in a nice inn with a great view of the ocean and a small brewpub across the street, I highly recommend the visit. Pelican Pub makes absolutely wonderful beers and I was lucky enough to have a tour of the brewery with the brewer, Darron Welch. Darron has mash hopped his winter warmer for the past few years (I acquired two bottles..lovely) and noticed that the runoff was crystal clear. I have noticed the same thing on a small scale and thought this too might be pH related...but Darron gave me a better explanation--surface area. He proposed that the increased surface area in the hopped mash gave more places for proteins and particulates to settle. It mirrors my observations and Darron mentioned that other breweries using mash hopping see the same thing. So there ya go! Regarding yeast pitching... The conventional wisdom is to not repitch after your high-gravity fermentation. I would say that a 1.060 IPA doesn't quite qualify as high-gravity, although others may differ. What I have done in the past when dealing with this issue is to pitch a couple of quarts of starter wort on the big yeast cake the day before. It gets the yeast chugging again, and the resultant high-gravity fermentation seems fine. However, I would bet you could pitch the same yeast through those three batches without ill effect. Cheers! Marc - -- Marc Sedam Chapel Hill, NC Return to table of contents
Date: Mon, 25 Aug 2003 09:17:23 -0400 From: "Dan Listermann" <dan at listermann.com> Subject: Electrical Element Wattage Density Dion Hollenbeck <hollen at woodsprite.com> posts on this subject. For years I have used common hot water elements to boil my brews. I run them at 240V. I have used a 5500W element and, if memory serves, it produced over 100 watts per square inch. I never noticed scorching, although there was beer stone build up that had to periodically be removed. I eventually changed to 4500 watts because the bigger one would boil over easily. I am designing a bigger system and will probably go back to 5500W. I don't foresee any problems if experience is any guide. Dan Listermann Check out our E-tail site at www.listermann.com Free shipping for orders greater than $35 and East of the Mighty Miss. Return to table of contents
Date: Mon, 25 Aug 2003 08:20:57 -0700 (PDT) From: Rama Roberts <rama at sun.com> Subject: re: you've got mail > I got about 5 from the HBD mail responder. As if the spam problem wasn't > enough, this starts to make email unusable as a communication media. > All the best and a spamfree homebrew Thomas Its been getting bad for me too- I've affectively modified my spam filter to catch the incoming sobig.f, but as janitor Pat mentioned earlier, its the bounces or autoresponders complaining about the emails with your address as the faked From address that really suck. They all look different, so its hard to positively identify and filter them. On a good note, Pat and I have been discussing a fix that will help limit future spam. The HBD archives expose email addresses as Mailto links- perfect for "scrapers" to harvest them and pass them on to spammers. Our plan is to convert those addresses, for example: billgates at microsoft.com to billgates AT microsoft DOT com or some such to prevent automatic scraping. Hopefully Pat and I will implement this quick fix in the near future. - --rama Return to table of contents
Date: Mon, 25 Aug 2003 09:20:27 -0700 (PDT) From: Calvin Perilloux <calvinperilloux at yahoo.com> Subject: CO2 Safety (again) "Tanksalot" in the previous HBD: >> To test my theory I "poured" a glass of CO2 gas and >> inhaled it, obviously I'm still here. The only sensation >> was the same you get from smelling the gas released by soda >> water. I'm not a chemist, so maybe someone more familiar >> with gases (is that a word?) can jump in... You didn't get a high enough concentration of CO2. Really. By "pouring" it, even though CO2 is about 1.5 times the density of air, you're mixing it and reducing concentration, probably below 20%, considering the effect you're talking about. Try instead purging a container (of liquid) with CO2 so that you get pure CO2 in there, and you'll get a nice nip in the nose, or more. I guarantee. Don't do this with a container you might fall into! Let me assure you that Drew and Ed didn't have something else in their fermenters causing that. John Koppens asks whether CO2's hazards come from air displacement or toxicity. I think it's a mix, and anyone considering this issue can do some thorough Google checks and get lots of data to add more detail to this: CO2 does have major effects even in concentrations where it's obviously not displacing enough O2 to cause such intense problems. This could be because the concentration in the air is inhibiting the respiration of it from your lungs, possibly even dissolving into the blood instead of out of the blood. And the formation of carbonic acid on the tender tissues in your nose/eyes/lungs is also something that you won't find with an inert asphyxiant like nitrogen or argon. More safety data, and then I'll stop, lest this thread never die, from the Canadian version of OSHA, some info on CO2 toxicity: http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/ carbon_dioxide/health_cd.html "Exposure to 10% for 1.5 minutes has caused eye flickering, excitation and increased muscle activity and twitching. Concentrations greater than 10% have caused difficulty in breathing, impaired hearing, nausea, vomiting, a strangling sensation, sweating, stupor within several minutes and loss of consciousness within 15 minutes. Exposure to 30% has quickly resulted in unconsciousness and convulsions. Several deaths have been attributed to exposure to concentrations greater than 20%. Effects of CO2 can become more pronounced upon physical exertion, such as heavy work." Calvin Perilloux Middletown, Maryland, USA Return to table of contents
Date: Mon, 25 Aug 2003 12:21:24 -0500 From: "Ronald La Borde" <pivoron at cox.net> Subject: Oxygen I am as guilty as everyone else who keeps listing O2 for oxygen. Apparently the atomic symbol is O, not O2. I was looking around and came up with this reference: http://pearl1.lanl.gov/periodic/elements/8.html Ron ===== Ronald J. La Borde -- Metairie, LA New Orleans is the suburb of Metairie, LA www.hbd.org/rlaborde Return to table of contents
Date: Mon, 25 Aug 2003 14:03:14 -0400 (EDT) From: Pat Babcock <pbabcock at hbd.org> Subject: O! O, nO! It's nOt O2! Greetings, Beerlings! Take me to your lager... pivoron at cox.net writes: > I am as guilty as everyone else who keeps listing O2 for > oxygen. Apparently the atomic symbol is O, not O2. Oh, Gads! Who picked THAT nit? Yes, yes, yes: the chemical symbol for Oxygen is O. However, nature doesn't care what symbol we chose for it. She refuses to allow Oxygen to travel alone. When you breathe it, it's coming with another buddy; hence, in nature, it's O2. Molecular oxygen; not atomic oxygen. Yeah, it's briefly O in the formation of ozone (O3); however, O is not stable, and we do not add O to our wort. We add O2. So stop picking nits already: when we're talking about oxygenation, it is quite proper to refer to it as O2. Nyah. Did you know that they've proven O4 exists? (http://www.nature.com/nsu/011122/011122-3.html). Back into the padded cell... - -- - God bless America! 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 [18, 92.1] Rennerian "I don't want a pickle. I just wanna ride on my motorsickle" - Arlo Guthrie Return to table of contents
Date: Mon, 25 Aug 2003 12:13:54 -0400 From: "Pete Calinski" <pjcalinski at adelphia.net> Subject: CO2 effects This may be an old wife's tale but I was told that when the concentration of CO2 in the lungs gets high enough, it forms carbonic acid and that causes the burning sensation. OTH, nitrogen does not have this effect so there is no warning that you are not getting enough oxygen. You just pass out. Thus, you will see nitrogen sensors in areas where nitrogen is stored. Pete Calinski East Amherst NY Near Buffalo NY http://hbd.org/pcalinsk *********************************************************** *My goal: * Go through life and never drink the same beer twice. * (As long as it doesn't mean I have to skip a beer.) *********************************************************** Return to table of contents
Date: Mon, 25 Aug 2003 13:13:07 -0600 From: "John Adsit" <j.adsit at comcast.net> Subject: Oxygen Toxicity > From: "Tanksalot" <tanksalot at rogers.com> > Kevin said, "actually even breathing O2 can kill you". (I assume, Kev, > that is a typo, as O2 is oxygen). I believe the point was that anything is toxic under the right conditions, and that is indeed true for oxygen. Central Nervous System Oxygen Toxicity can occur when breathing too much O2 under more than one atmosphere of pressure. It causes immediate seizures. Scuba divers who use enriched air (Nitrox) need to know the depth limit for the particular blend they are using, and they should track the O2 buildup over repeated dives. Seizures from CNS toxicity are usually fatal, since the diver will probably drown. Pulmonary oxygen toxicity causes damage to the alveoli in the lungs, and it is associated with breathing high concentrations of O2 at normal pressure over a prolonged period of time (like days). Of course, this is not something that brewers need to worry about, unless they take up diving as well. But the actual point is valid: enough of anything under the right conditions can kill you. John Adsit Boulder, CO j.adsit at comcast.net . Return to table of contents
Date: Mon, 25 Aug 2003 18:51:16 -0400 From: "Dave Burley" <Dave_Burley at charter.net> Subject: Bubbles, Tiny (and big) Bubbles Brewsters, /Fredrik is counting CO2 bubbles in the airlock. I did this at the beginning of my brewing career also, so I understand. One thing you must remember is that CO2 is soluble in water/beer and this will skew your results, as the fermentation can proceed for a while before any bubbles come out. Temperature is a problem to be accounted for, as solubility of CO2 is temperature dependent. But the largest variable and least accountable for variable is the fact the CO2 in a water system is slow to come to equilibrium ( and thank goodness!) were it not, we would get a shower of beer every time we opened a bottle. You could try agitation during fermentation or other mechanical means to bring the CO2 to equilibrium, but this has apparently ( IOW , jury is still out in my book) been shown to have adverse effects on beer quality. Point is, bubble counting is not a good measure of fermentation rate until the fermeting fluid is saturated and not even then due to the non-equilibrium release of CO2. Keep on Brewin' Dave Burley Return to table of contents
Date: Mon, 25 Aug 2003 19:00:02 -0400 From: Bob Hall <rallenhall at toast.net> Subject: Toronto Tips My wife and I will be in Toronto for a few days in September and will be staying at the Delta Chelsea, 33 Gerrard Street West. We won't have a car, so any tips about brewpubs, beer bars, or beer supply stores in that part of town would be appreciated. Many thanks. Bob Hall, Napoleon, OH Return to table of contents
Date: Mon, 25 Aug 2003 18:06:51 -0700 From: "Mike Sharp" <rdcpro at hotmail.com> Subject: 240V vs 120V... I had to chime in on Dion's cautionary post... >>Gary Smith writes: GS> I would like to find a leg from the other side of the breaker box, GS> add another Solid State Relay and connect it as 220V just to GS> accelerate the ramping times during mashing somewhat. And Dion emphatically states: "DO NOT, I repeat, DO NOT do this." And also states: "Caramelization and localized denaturing of enzymes are sure to happen if you run the heater element at its full heat capacity on 240V." I have to respectfully disagree. Nobody said anything about running the heater element at full capacity...he simply said he wanted to run it at 240V. He's using a PID controller, not connecting it across the line. Line voltage and power are not related here, because the power is controlled by time domain proportioning. Depending on the tuning of the controller, he can run the heater at any wattage from zero to 6000W. It entirely depends on the proportion of the "on" time to the "off" time. This can be set in the controller. Let's say he wants to slightly increase the ramp rate. What he really wants is, say, 1800 watts instead of 1400 watts. Assuming he has a cycle time of about 1/2 second, at 240 volts he'll have to set the maximum percent so that the max "on" time is about 23% to produce 1400 watts of heat, or 30% to produce 1800 watts. On an Omege controller (well, on the CN7700 series), you do this by specifying the the value in the Maximum/Percent High submenu. The actual maximum watt density he can use without carmelization is going to be dependant on several factors, one of which is flow rate. But in his case, I see nothing wrong with using 240volt on the heater, when a PID controller is involved. Obviously there is a maximum desireable watt density, and he'll have to determine his maximum ramping rate some way. Personally, I prefer instrumented heating elements. These have a thermocouple installed inside the rod, bonded to the surface. These are nice because you know exactly what the rod surface temp is. But Gary's heater rod can easily be run at 240v, using PID control. Regards, Mike Sharp Return to table of contents
Date: Mon, 25 Aug 2003 21:43:00 -0500 From: "Rob Moline" <jethrogump at mchsi.com> Subject: Dr.Cone Responds-Follow Up Questions- Steve Alexander Dr.Cone Responds-Follow Up Questions- Steve Alexander Great thanks for considering my questions Dr.Cone. Many HBDers like to store yeast slurries. Storage under finished beer or deionized water at refrigeration temperatures is common. Some homebrewers reuse these stored slurries after as much as 60 days of refrigeration ! I have very grave concerns about the vitality and viability after such long storage and think that 30 days storage is pushing the envelope. 1 - What is an acceptable figure for pitched yeast viability (say by a haemocytometer + MethylViolet stain count). Is the commercial target of 90% viability too stringent for the homebrewing environment ? 2 - What is the viability of properly rehydrated dried yeast like Lallemand's ? 3 - Please comment on the expected vitality and viability of a wet homebrew slurry stored at refrigeration temperatures for various periods. Obvious there is no definite answer to such a general question, but perhaps you can suggest how long is 'probably OK' ? How long is 'likely too long' ? 4 - Some yeast vendors package wet yeast in refrigerated 'pitchable' tubes. Is there any means that they could employ to improve the yeast storage properties beyond that of a homebrewer's refrigerated slurry? For example, does anaerobic handling or phosphate buffers, etc improve 'fridge shelf life of a wet slurry by a great amount ?. 5 - Does the iodine test (iodine into slurry sample to detect glycogen) have any comparative value to homebrewers as a quick and dirty test of slurry vitality ? [Some sources state brief exposure to O2 will rapidly deplete yeast glycogen .] 6 - What are the consequences of pitching low viability slurries given that sufficient viable cells are pitched ? If I pitched one unit of 100% viable slurry versus 3 units of 33% viable slurry what would be the expected difference in the beer ? Autolyse of non-viable cells ? Other ? Does racking the beer off trub to a secondary prevent this harm ? On a different topic ... Many HBers build up large yeast starters, but they do not wish to dilute their 5 gallon batch of XYZ-style wort with several quarts of pedestrian starter wort. They wish to separate the yeast from the starter wort before pitching. Many will allow the starter fermentation to nearly complete then refrigerate it and allow the yeast to sediment before decanting and pitching . 7 - Does the <attenuation, refrigeration, sedimentation, separation> process hold potential harm for the yeast ? For example is the yeast likely to be less vital than if pitched directly from a high kreusen starter ? Yet another direction ... 8 - Is there any significant advantage to *very* short 'lag times' (time between pitching to first sign of fermentation - usually CO2 outgassing) ? Many HBers seem obsessed in reducing lag times from 8 hours to 5. Personally I doubt it makes much difference so long as the lag period is reasonably brief. I know that 8 koans in Cone's fountain is a bit, but hopefully some admit concise answers. thanks again, -Steve Alexander Steve Alexander, Good straight forward questions. I wish that I had good, simple, short answers. You have a right to be concerned about the quality of the yeast stored under refrigeration for as much as 60 days. Some people may tell you that they do it all the time and still have successful fermentations with it. The gods must be looking after them. My answers below are shared comments by my collegue Dr. Tobias Fischborn. Ad 1) the viability for liquid culture (crop yeast) is also an indication for the physiological state or vitality of the yeast. If the viability is relatively low then there was something wrong (stress, nutrient deficiency...) during the previous fermentation and the "viable yeast" is probably not in very good condition as well. Therefore a viability of more than 90 % would be good standard to maintain. Ad 2) For dry yeast it is a bit different. Here some yeast will die during the drying process and even more during the rehydration process. But this is an unavoidable process related loss and does not say anything about the physiological state of the viable cells. You will always have higher numbers of dead cells in dry yeast. The vitality of each live cell will be great. Usually the viability will be greater than 85%. The viability will be above 90% after a few multiplication cycles. Ad 3) It depends on how you store your yeast. There are reports that you can store yeast up to 1 year in distilled water if all sugars are removed. We have a little program running to test this and after one month the yeast is still fermenting well. But it is critical that all sugars are removed. A lot of breweries keep their yeast for up to a month under water (removing the wort/sugar residuals) without any problems. Ad 4) to my knowledge they are no special tricks to improve shelf life of commercial liquid cultures. These commercial cultures are propagated in nutrient rich media under optimum conditions means the yeast is very healthy when harvested and can be stored longer than crop yeast from a fermentation. Ad 5) For the iodine test you need a microscope. Other wise you don't know if the starch/glycogen you are detecting is inside living yeast or if it is in the medium coming from starch residuals in the wort or released from dead yeast. Oxygen will deplete glycogen in yeast. Ad 6) see ad 1. 100 % viable pitching yeast is very vital (healthy) compared to the 30 % viable yeast. So even if you compensate with a higher pitching rate you will have problems in the fermentation. Autolyses of non-viable cells is definitely an issue. Ad 8) You are probably right!! I don't believe there is a significant advantage in-between 5 hours and 8 hours lag time. It is when the lag phase begins to extend well beyond this time period that you would begin to suspect a weakening of the pitching yeast. The HBers that try to keep the lag phase below 8 hours and moving down toward 5 hours are to be complimented on their efforts. It means they are doing all they can to keep a healthy yeast for pitching. Clayton Cone - --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.512 / Virus Database: 309 - Release Date: 8/19/2003 Return to table of contents
Date: Mon, 25 Aug 2003 21:52:15 -0500 From: "Rob Moline" <jethrogump at mchsi.com> Subject: Dr. Cone Responds-Top 5-David Sweeney Dr. Cone Responds-Top 5-David Sweeney Dr. Cone: My brain is about to explode with all of the biochemistry (they don't call it BICH for nothing!). I took it in college but try not to think about those horrible days. In Fix's book _Principles of Brewing Science_, George outlines a list of the most critical controllable elements of the brewing/fermenting process for homebrewers, for example, fermentation temperature, pitching volume, etc. Since I is a Aggie, I have trouble with lists larger than I can count on one hand. So my question is this: What are the top five controllable variables (in order of importance) with regard to yeast for the homebrewer? David Sweeney Texas Aggie Brew Club (TABC) David, I agree. My mind gets migraines too from trying to remember all the biochemistry, metabolic pathways and genetics. Thank goodness, some smart fellows have figured it all out for us. It has erased a lot of the mysteries and explains why all the controls are necessary and what goes wrong if you don't have controls. Dr. Fix was great at explaining in layman terms. I wish that I had his talent. I have spent over 55 years working with yeast: R&D, Q.C., production and its industrial application---baking, pharmaceutical, brewing, distilling and winemaking. The one common denominator for a successful fermentation in each field has been "healthy yeast cell". Concentrate on starting with a healthy yeast and ending with a healthy yeast. If you Re-pitch, store as cold as possible (4C) and start with a new culture as often as possible. After 5 cycles you are taking a chance with infection build up. After 10 - 15 cycles you are taking a chance with petite mutates, genetic drift, cell wall hydrophobicity change and flocculation characteristics. If you are not critical about fermentation time and the flavor profile you may get away with more re-pitching cycles. If you are critical about fermentation time and flavor profile then you will hold re-pitching to a minimum. Temperature control is right at the top of the list of variables to control, starting with the mashing temperature. If you skip the protein enzyme phase around 45C you will end up with a wort that is low in amino acid nutrients for the yeast. 68C mashing will give you an entirely different sugar profile with less fermentable (more unfermentable) sugars than 60C mashing. Several cycles with low nitrogen will begin to produce a weak yeast. An increase in unfermentable sugars will lead to higher attenuation gravity and you will be wondering why the fermentation does not attenuate. Good beer can be made from extracts, however, you must remember that some to all amino acids are tied up by the Maillard reaction during the preparation and storage of the extract. Consider adding a well balanced yeast nutrient like Fermaid K to an all malt extract fermentation especially if you are going to Re-pitch. This will go a long ways towards maintaining a healthy yeast cell. A product like Servomyces will give you yeast an added boost. Higher gravity wort with increased levels of sugar require more well balanced nutrients supplementation, especially as you begin to re-pitch. Follow the yeast supplier's instructions very carefully for start up.. The Active Dry Beer Yeast rehydration instructions are extremely important. Success and failure begins at this point. With a healthy yeast, pitching rates are easier to estimate. You do not have to guess at how much over pitching that you need to make up for poor yeast health, viability and vitality. You asked for the five most important variables to control in order of importance and I have talked around your request by emphasized the health of the yeast cell. With a healthy yeast, controlling the variables becomes meaningful. If I have to list five variable that should be given careful attention: Wort preparation and composition Yeast strain Pitching rate (and storage) Fermentation temperature Well balanced nutrients Oxygen (this can be considered a nutrient also) My answer may not be as precise as you would like. Perhaps it will open a dialogue. Clayton Cone - --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.512 / Virus Database: 309 - Release Date: 8/19/2003 Return to table of contents
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