HOMEBREW Digest #4765 Mon 25 April 2005

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  Re: Subject: Fermentation, Esters, Fusels ("Fredrik")
  Motorizing a Phill Mill (Danny WIlliams)
  Re: Cheap goodies -- hot liqour tank/mash tub/brewkettle level gauge (Dan Fink)
  RE: Motorizing a Philmill ("Ronald La Borde")
  re: Pellets, Flowers & Kettle drains ("Michel J. Brown")
  re: Reculturing yeast from previous bottled brews ("Michel J. Brown")
  Whirlpooling ("Spencer W. Thomas")
  Phoenix/Scottsville AZ ("laraeder@juno.com")
  re: Where to cut kegs ("Mike Westcott")

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---------------------------------------------------------------------- Date: Mon, 25 Apr 2005 09:33:53 +0200 From: "Fredrik" <carlsbergerensis at hotmail.com> Subject: Re: Subject: Fermentation, Esters, Fusels (I had to cut the post size, 2nd attempt= Hello Matt, FWIW, here are some comments. I guess you'll get more comments from others. Yes, the motivation for the cell to do anything is to grow and reproduce, and finally when food and nutritions is limiting it is a matter of surviving through starvation - switching priorities. All growth would have been wasted unless each cell prepares and orderly shutdown and prepares for starvation so that as many as possible survives until next feeding. I persoanlly think yeast responses are more easy to understand if you think of it this way. Some regulation switches from growth to stationary phase, can probably be more easily understood if you think of it in these terms. If you just look at the single reaction chemistry it is almost impossible to understand the "why" question. I think many organisms share the very same why's, while the how's differ. That is why I think why is more fundamental than how. In order to do that, and in order to understand, it is alot easier if you consider the entire organism, and what is driving it. Why has probably been the same since way back, while the "how" is constantly changing and been optimized by evolution. I think why is more interesting than how. I think of the set of chemical reactions in the cell of a very well and carefully chosen way, to perform what the host organism wants. > 3. Hence, in a decent fermentation the total yeast > growth is proportional to the amount of sugars > consumed (i.e. a specific amount of yeast growth is > required for a given beer). I think Steve agrees with > this. This is eqvivalent to say that the batch-average biomass yield is always the same which I guess would be a good first approximation! (Though different factors must modulate the biomass yield) Yeast growth = total amount of new biomass produced To get a ballpark feeling, 1 g fermentable sugar usually generates *the order* of 1 billion new cells. The reason has to do with the energy requirements for building biomass. So 5 gallons 12P wort at 65% fermentability would give you 1476 g fermentables. So as an estimate fermenting that normally generates *the order* of 1476 billion NEW cells (the same count as about 7 packs of dry yeast). > 5. Since we require a given amount of growth, choosing > the pitching rate is the same thing as choosing how > many generations of yeast will have to be produced. > (!) I agree. The typical pitching rate recommendations of 1 million/ml/P usually menas each cell on average has to divide close to 3 generations. a 50% reduction of the pitching rate increases the times each cell has to divive byt a factor 2. Some ballpark numbers 0.25 million/ml/P -> ~5 generations 0.5 million/ml/P -> ~4 generations 1 million/ml/P -> ~3 generations 2 million/ml/P -> ~2 generations 4 million/ml/P -> ~1 generation As the generation #n increases, the relative cellular level of oxygen derived compounds drop as 1/(2^n), impacting ont only performance, but also as has been reported alcohol tolerance. So for higher gravity beers, you probably need to get the generations# down to keep the same performance. (Of course this is only crude estimates) > 6. To keep reproducing for a given number of > generations, the initial yeast cells must store up > enough cell-wall material (sterols). Oxygen is > required to make this material. It cannot be made > once fermentation activity is significant, because the > oxygen is quickly scrubbed out of the wort by the CO2 > bubbles. (I am ignoring trub and late oxygen > additions.) Hence, the fermentation go to completion > only if the average cell of pitching yeast gets enough > oxygen to make and store enough sterols to reproduce > for the required number of generations. I am not sure about the O2 beeing scrubbed ou by CO2 part but, the initial levels of oxygen derived compuonds once yeast has depleted the initial O2 would definitely have a huge impact on the performance during fermentation. I think the first and most commong sign is poor performance (longer primary times), and within limit you can probably toy with this to tweak other things. I think serious attenuation problems are extreme cases. If one consider the 1/(2^n) thing - it is easy to see a relation between pitching rate and aeration. > 7. Some or maybe even all of this oxygen can be > provided in a yeast starter. Hence, for those of us > without oxygen tanks, etc, making a well-aerated yeast > starter can really help. Yes I am convinced you can do this. I do this all the time. I never aerate the wort. Instead I prepare the yeast in steps. The reason I do this, is because first of all it is alot easier to aerate a starter flask, than to aerate 5 gallons of wort. Second I feel that I have more control over the yeast this way, I can aerate it multiplie times to make sure it's good, without having to balance as much against the possible issues of oxidating anything in the wort. The major part of the starter growth can be done as usuall, just in room temp + let if finish, decant. The remaining steps I make are shorter, and serve only to prepare the yeast and utilized oxygen. I usually make the very last step very cold, even ale yeasts I try to get going in the fridge in some easily digested medium, I've tried sucrose with some yeast nutrition in it because it's easily digested, sometimes mixed with wort. Aerate well during the cold adaption phase. I have been amazed how ale yeast can perform in cold given the right preparation. I think that the cold triggers yeast to increase it's utilisation of oxygen, for UFA's and sterols, perhaps also trehalose to adapt. Then 30-60 mins before brewing I take the yeast out of hte fridge and let it hit pitching tmep. I've had short lags, and excellent performance (quick primary times). I think one thing is to make sure the yeast utilises the oxygen you add better. Blindly flooding the wort with pure O2 for 30 minutes is hardly the best. It's probably like feeding a kid without paying attenuation to that it's mouth is closed. It is not enoug to get the oxygen into the wort, you also have to make sure the *yeast* "can" and will use it. If you pay attention to when the mouth is open, you can probably do the same job better with far less waste and side effects. 1) I wouldn't aerate yeast that has been starving for a long time. It has depleted it's energy reserves and doesn't have the energy it takes to utilize oxynge efficiently, and it's probably better to reenergize them, and *then* aerate again. 2) I suspect that aeration carried out at lower temperatures causes much better utilisation of O2 than at higher temps. I haven't seen it explicit for yeasts, but other organisms like E.Coli has been reported to regulate it's membrane UFA/SFA ratio in response to temperature. And considering the universal nature of cell membranes it is not unlikley that some similar phenomenon occurs in yeast too. I think of the cold-aeration techniqued as a supercharging procedure. I have done this with excellent performance so I can't see that it doesn't work well. > 8. For a given temperature and yeast strain, there is > basically a set amount of fusel, ester, and diacetyl > production that will occur during a full, strong > fermentation. Pitching rate, aeration level, etc, > don't matter much as long as the fermentation is I am doubtful to this simplification(?) that the amounts should be set. Wort composition are bound to matter alot too to mention one thing. The amino acid profile and also maybe sugar profile. I think a higher pitching rate and higher aeration generall leads to higher total biomass growth, and probably also a *later* biomass yield drop near EOF, which probably has some impact too? /Fredrik Return to table of contents
Date: Mon, 25 Apr 2005 10:56:01 -0400 From: Danny WIlliams <dbwill at gmail.com> Subject: Motorizing a Phill Mill > Dan Listermann writes,"I'm curious as to why there is a warning > in the manual about not motorizing the Phil's mill? " I am not > sure where he got this idea but the instructions actually tell > you how to motorize the Philmill. > We highly recommend powering Philmills with 1/2" corded > electric drills. They can triple manual throughput with a whole > lot less sweat. I recently bought a PhilMill 1 and recall a page of instructions that included the warning about *motorizing* because of the risk of damaging the roller and/or plate with rocks or bits of metal that are sometimes found in grain. It does recommend using a *drill* (rather than a belt driven or direct drive mounted motor) and holding it in your left hand so that if an obstruction is encountered the drill will rotate out of your hand and stop rather than rotating into your hand and possible injuring your wrist. Return to table of contents
Date: Mon, 25 Apr 2005 09:27:12 -0700 From: Dan Fink <danbob at direcway.com> Subject: Re: Cheap goodies -- hot liqour tank/mash tub/brewkettle level gauge -One copper toilet float ball (buy it NEW, please!) -One stick of 1/8" threaded rod -One stick of aluminum channel and a C-clamp to hold it on top of the kettle -One stick clear plastic tubing -One sharpie Mark your threaded rod and plastic tube at empty. Pour in water one gallon at a time, and make marks on the plastic tube every gallon. My hot liquor tank is a 1/2bbl keg that's up in the air, the level gauge is cheap, slick and means I don't have to climb up to look in all the time. ;~) DANF Return to table of contents
Date: Mon, 25 Apr 2005 11:07:29 -0500 From: "Ronald La Borde" <pivoron at cox.net> Subject: RE: Motorizing a Philmill >From: "Pat Babcock" <pbabcock at hbd.org> > >...the paperwork >received with the beast back in the day used to admonished the buyer against >doing so, lest the winged beasts of Warranty would come fly over and void upon >you. Or something like that. Your memory is correct, but that setscrew attached handle is oooohhhh so tempting! I could not resist! I think by using a flexible coupling, the shaft will last longer than the brewer, but haven't found out as of yet. The winged beast can take a look at: http://hbd.org/rlaborde/maltmill.htm 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 Apr 2005 11:28:19 -0700 From: "Michel J. Brown" <zymurgyst at comcast.net> Subject: re: Pellets, Flowers & Kettle drains Mike Maag says: >I have found, what you need to do is let the wort sit (or set) for about 1 >hour after chilling, >before you start to drain the kettle. Whirlpool, >cover, and let the wort sit for at least 1 hour.. This sounds a little hazardous to me, from personal experience. I can see letting the settlement occur for 15-30 minutes, but a full hour? I dunno about that, Mike, I used to have problems in that area until I started chilling immediately after the boil. Then everything went as smooth as silk! >Don't use Irish Moss!! It gunks up's the trub too much.. you don't need >it. Well, fwiw, IM is only useful in very light colored worts in the first place, and that usually and customarily won't have a whole lot of hops. Unless you're trying to make an IPA that is. >As long as you let the wort settle out, the pellet stuff will be settled >out too. Aye, there's the rub! In my own personal experience, I've found that break material, and hop pellet material will be interspersed with each other, but as a caveat, YMMV. >It helps to have a ounce of flower hops in the boil. Just a handful of >homegrown hops will help >keep the trub in a nice pile in the middle of the >kettle. While this is more than likely the scenario, I seem to remember that the original poster used pellet hops almost exclusively, but for the occasional exception with the use of plugs. This is why I prefer whole leaf hops, they just seem to work better for me, and make cleanup that much easier. >My system has a copper pipe circle with hacksaw cuts every 1/4 inch on the >bottom. But the main >point is to let the stuff settle before you start to >drain. That's a good point, Mike, but as I also remonstrated in earlier posts, the sooner you chill the wort, the better. Settling of whole leaf hops is much faster than pellets IMHO, so that may be the difference. Btw, how wide are your cuts in your copper pipe circle, and are they facing up, or down? I dunno if that will make a difference or not, but since you use an apparent mixture of hop types, and it works for you, the problem is then moot? >Otherwise, the pellet stuff in the wort can clog the screen (or whatever) >as the wort drains. This sounds like the main variable will be the surface area of the drain, as the settlement comes in contact with it. In my case, the surface drainage area compared to the total volume is huge, while yours is relatively lessened, and the other Mike's is probably somewhere in between. I usually get all but a quarter of a cup of wort out of my boiling tun after draining the sweet wort from the settlement. But, if I use pellet hops (first time I used my modified EZ masher), like the Liberty hops that went into a CAP I was making. I ended up having to use my immersion chiller with my racking cane and skirt in order to drain my tun completely, and I left about a cup or two of wort that one. >Hope this helps, >Mike Maag Different POV's are usually a good thing IMHO. It helps to find something that might work for somebody's peculiarities in their particular system. Prost! Michel Somewhere in the unfashionable eastern end of Mutter's Spiral in the Milky Way - -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.10.3 - Release Date: 4/25/2005 Return to table of contents
Date: Mon, 25 Apr 2005 11:47:47 -0700 From: "Michel J. Brown" <zymurgyst at comcast.net> Subject: re: Reculturing yeast from previous bottled brews >I am relatively new to brewing and I have the following question which >may be obvious to more experienced brewers... Welcome to one of the very best hobbies you can enjoy! >I have read about re-culturing yeast from bottled commercial beers. >Are there any major problems with doing the same from previous beers >that I have brewed and bottled? >From personal experience, (and I have a doctor's degree -- had to do a *LOT* of culturing) reculturing from a bottle of commercial beer is highly problematic. First, you don't know the age of the bottle, second, you don't know what the viability is of the yeast is in the bottom of the bottle, third, you're not even sure if the yeast in the sediment is the same as is used in the original ferment. Also, in bottles of your own beer, the yeast will autolyse over time in addition to being very stressed out metabolically, and physiologically. If you really want to preserve yeast for future use, just take a sterile (as possible) bottle, add sediment from the bottom of your fermenter, and top off with the cheapest commercial beer you can find, then bottle with an oxycap, and keep at just above freezing. (35-38'F). This is what I do, and yeast have lasted as long as a year this way (I forgot about some I kept like this) and the yeast were quite able to start back up in their new home quickly. >Recently I brewed a English bitter ale using Wyeast 1098 British Ale yeast >which I bottled. If I re->culture yeast from one of these bottles will it >have the same viability and performance as from the >original smack-pack? I really doubt that it would. Its possible that you probably wouldn't notice the difference, after stepping up the starter a few times, but I'm still kinda leery of what you're doing here Oisin. >I have heard of storing yeast between brews in the fridge using various >mediums etc. but it would >seem to me far easier just to re-culture the >yeast from a bottle of the previous brew, especially >since I am not able to brew very often. Why don't you try my method? It's very simple really, and gives you a lot more healthier yeast with which to work. As you don't brew that often (which begs the question of frequency), this may help alleviate you of a knotty problem. I brew every week, so yeast propagation isn't much of a concern to me as it is for you. Hope this helps, good luck, and God Bless! Prost! Michel Somewhere in the unfashionable eastern end of Mutter's Spiral in the Milky Way >Thanks, >Oisin. - -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.10.3 - Release Date: 4/25/2005 Return to table of contents
Date: Mon, 25 Apr 2005 17:02:06 -0400 From: "Spencer W. Thomas" <hbd at spencerwthomas.com> Subject: Whirlpooling Michel (zymurgyst at comcast.net) writes: > The centrifugal force applied results in the (relatively) higher weight > (mass) particles to go to the sides and bottom, while the lighter ones stay > on top. I'm not sure of the mechanism, because it seems counter-intuitive, but in fact all the trub ends up in a cone in the center of the pot. This is the stuff that is clearly heavier than the wort, since it settles naturally to the bottom. But by whirling, it is somehow forced to the center. You can see the result in the picture here: http://homeroastnbrew.info/homebrew/chilling/ In this picture, more than half of the wort has already been drained from the kette, so the cone of hops & trub shows up very nicely. =S Return to table of contents
Date: Tue, 26 Apr 2005 00:13:20 GMT From: "laraeder at juno.com" <laraeder@juno.com> Subject: Phoenix/Scottsville AZ HBD, I will be in the scottsville/Phoenix Arizona area next week and would appreciate any sugggestions for good beer bars/brewpubs, preferably a couple within walking distance of each other as I will not have a car. HBD traffic is light but replies to my personal email might be best. Thanks, Dana Edgell Return to table of contents
Date: Mon, 25 Apr 2005 17:38:23 -0700 From: "Mike Westcott" <mwesty at cableone.net> Subject: re: Where to cut kegs Thanks for the replies. Looks like we'll find some lids, make some plasma cuts and go to it! Return to table of contents
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