HOMEBREW Digest #4636 Sun 24 October 2004

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  FOY-2004-Response - Reusing Yeast (jethrogump)
  FOY 2004-Response-windsor/nottingham (viable cell count) + glycogen/iodine (jethrogump)
  FOY-2004 (jethrogump)
  More Sugar Confusion ("Phil Yates")
  Galv Gas Pipe (Moses Rocket)
  Re: PH adjustments ("Martin Brungard")
  BONES Bash 2004 Competition (Bruce Millington)
  serial vs parallel ("Dave Burley")
  Sources of FAN (free amino nitrogen)? (Bill Velek)
  link of the week - Australian craft brewing (Bob Devine)
  New Hop Information Resource ("Scott D. Braker-Abene")
  FOY - Rescuing Old Yeast (Grant Family)

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---------------------------------------------------------------------- Date: Sat, 23 Oct 2004 03:55:43 +0000 From: jethrogump at mchsi.com Subject: FOY-2004-Response - Reusing Yeast FOY-2004-Response - Reusing Yeast I have begun to reuse liquid yeast from my homebrewing and was wondering whether it is better to save yeast from the primary fermentation or the secondary fermentation? I've heard that it is a decision whether to save "dirtier but vigourous yeast cells", or "cleaner but tired yeast cells". What is your opinion on this? keep in mind that I typically do not perform a washing procedure on the saved yeast. It is stored in a sterile Mason jar. When I am ready to brew, I make a starter, bring it back to life and pitch. Thank you very much for your time. William Erskine William, Most commercial brewers harvest the yeast from the main/primary fermentation while the yeast from the secondary fermentation is discharged. But their wort is in general "pre cleared" in a whirlpool, separator or sedimentation tank. Their crop yeast is not as "dirty" as in home brewing and often they wash their yeast as well before re-pitching it. So yes I would agree that in home brewing the yeast from the secondary fermentation is cleaner than the crop yeast from the primary. If the yeast from the secondary fermentation is weaker I am not so sure. Usually you transfer the yeast that is still in suspension to secondary fermentation. This is the vital yeast whereas the exhausted yeast cells settle to the bottom. So at the beginning of the secondary your yeast is at least as vital as the crop yeast from the primary. Then it depends when you harvest the yeast. If you harvest the yeast as soon as the secondary fermentation is finished the yeast should still be vital but if you leave the yeast for a long time in your beer than it might not be worthwhile harvesting the yeast. You also have to consider that there is lower yeast concentration in your secondary fermentation than in your primary, means you might have not enough yeast to start the next fermentation. Regards Forbes & Tobias Return to table of contents
Date: Sat, 23 Oct 2004 04:07:48 +0000 From: jethrogump at mchsi.com Subject: FOY 2004-Response-windsor/nottingham (viable cell count) + glycogen/iodine FOY 2004-Response-windsor/nottingham (viable cell count) + glycogen/iodine Dr. Fischborn and Dr.Waldrop. Some time ago I was counting cells and then looked at the datasheets for windsor and nottingham and it says(among other things:): Nottingham contains >= 5 billion viable cells / g(dw) Windsor contains >= 7 billion viable cells / g(dw) This got me curious. I have come up with two interpretations of this, either that the nottingham cells are simply bigger and you only get so many into a gram, or the nottingham strain are more sensitive to the drying process in the sense that you get a little bit more dead cells per gram. 1) Can you explain why there are more windsor cells/g than nottingham cells? 2) Setting aside viability, what is the typical actual total cell count per gram Nottingham? ( I did a count some time ago, and though my methods are very crude and homemade (using estimates drop volumes), and may give errors, I arrived at a much higher count, around 20 billion/g. It did only one count, so there may have been error, but I am doubtful that my error is that large, or if the numbers you guarantee are rather on the low side to be safe? I never repeated the experiment so I could have been in error, but it would be nice if you can confirm what is the excepted actual total cell count, rather than the minimum guaranteed viable cell count) 3) I have tried to determine the glycogen contents of yeast slurry, by means of taking a digital picture of the iodine stained cells, and then translate the colour scale into a relative glycogen value (0-100%). Just looking at the colour resolution I think it might be realistic to resolve the glycogen level to maybe 4 intervals, 0-25%, 25-50%, 50-75%, 75-100%. What do you think about this? Is the correlation between intensity of the staining and glycogen level good? These are one of the few the relatively simple methods that does seem practical for any homebrewer with a microscope and interest since you don't need any hard-to-get chemicals or other lab equipment. The question is, is it reliable for ballpark estimates of glycogen? (provide the camera exponation settings are the same) In my firsts tests the glycogen drop I arrived at seemed to make sense. It dropped from the 75-100% range to the 25-50% in two days starving at room temp in a closed bottle (noO2). Does this make sense to you? http://hem.bredband.net/frerad/beer/modelling/pictures/glycogen.jpg (the optics in my simple microscope is limiting, that's why it's blurry) The pics are actually from a way outdated pack of windsor that I had saved for experiments. The low glycogen, left is the outdate pack. The right picture is how the outdated pack looks like after getting a little bit of sugar to eat. Once the sugar finished and two days later at roomtemp (still on under the beer) the level had dropped significantly judging from the colour. /Fredrik Fredrik, Yes, Nottingham yeast has usually larger cells than Windsor yeast and Lager yeast has even larger cells than the Nottingham. The viabilities mentioned on the technical data sheets are minimum viable cells per gram that we guarantee determined by plate count on YPD-agar. Usually the viability is higher. There is a slight difference in how resistent the different strains are to drying and rehydration. Usually ale yeast strains are more resistent than lager yeast strains. You might also consider that you will find much higher cell numbers under the microscope than by plate count, even if you have 100 % viability because you do not always have a single cell forming a colony but rather two or more cells. For Nottingham yeast the average cell count under the microscope is around 20 to 30 billion cells per gram dry yeast. As for the glycogen pictures you showed, this is quite interesting and there have been attempts in the past to use image analysis in such a way. Using the level of glycogen in this manner is quite simple but perhaps the scale you are using may be a bit confusing or misleading. I believe you may want to recalibrate your scale. Glycogen can be analysed in the yeast but I would guess you could reduce your scale by a factor of 2.5 and you may not be too far off. Certainly brewing yeast have been known to accumulate up to 40% glycogen. Regards Forbes & Tobias Return to table of contents
Date: Sat, 23 Oct 2004 04:20:23 +0000 From: jethrogump at mchsi.com Subject: FOY-2004 Folks, Am currently traveling and doing this by web-mail, not my fave.... Please excuse any glitches... Gump Return to table of contents
Date: Sat, 23 Oct 2004 22:43:30 +1000 From: "Phil Yates" <phil.yates at bigpond.com> Subject: More Sugar Confusion Alan Meeker comments: >My associate Phil Yates asks, what /practical/ use is there in discussing >the details of yeast sugar utilization? Well Phil you are correct, this >topic isn't likely to have much (if any) practical benefit to the average >homebrewer. Well thanks Alan, at least you are honest enough to answer my question. I'm certainly not suggesting that technical discussion should not exist on HBD. >Remember, the PgDn key is >always nearby... :) Well it was, but after years of using it whenever Mr "S" popped his head up, it eventually welded itself to the key board and I had to have it surgically removed. Now I'm puzzled by this post: >dglucose/dt = - fg(x)*glucose*yeast_active + >+ 0.5 * [ - fs1(x)*sucrose*invertase_wort - >fs2(x)*sucrose*invertase_surfacebound ] >dfructose/dt = - ff(x)*fructose*yeast_active + >+ 0.5 * [ - fs1(x)*sucrose*invertase_wort - >fs2(x)*sucrose*invertase_surfacebound ] >dsucrose/dt = - fs1(x)*sucrose*invertase_wort > - fs2(x)*sucrose*invertase_surfacebound >dmaltose/dt = - fm(x)*maltose*yeast_active >dmaltotriose/dt = - fmt(x)*maltotriose*yeast_active Clearly, I have been reading the wrong brewing books and missed out on such simple brewing details. By some stroke of fate, I've been brewing bloody good beer without understanding any of the basics at all. I really must do something about my ignorance. You just can't carry on enjoying your beer all your life! Phil Return to table of contents
Date: Sat, 23 Oct 2004 06:40:44 -0700 (PDT) From: Moses Rocket <mosesrocket at yahoo.com> Subject: Galv Gas Pipe Black schedule 40 steel pipe is generally your safest bet for gas piping, but it is not mandatory as some here seem to think. There is generally no problem using galvanized steel pipe for gas piping. Most building codes in the US and Canada now allow either black or galvanized for gas piping, as well as soft copper tubing and the new flexible plastic coated stainless steel tubing (CSST). (But check with your local code office, they may still have old antiquated codes on the books) There are a couple of things to watch out for: Copper tubing can not be used if the gas supply contains more than an average of 0.3 grains of hydrogen sulfide per 100 standard cubic feet. Hydrogen sulfide can cause corrosion and embrittlement in copper. (Most gas supplied these days has had any hydrogen sulfide removed so this is rarely a problem, check with your gas company) Copper tubing with flare fittings is a whole lot easier to work with than heavy black or galvanized steel. Galvanized pipe was not allowed in the past because many waterlines in houses were installed with galvanized pipe. Black was specified for gas to tell it apart from the waterlines. Nowadays, galvanized steel is seldom used for waterlines, so the codes have changed and now allow galvanized for gas lines. Many codes do require that exposed gas piping that is NOT in black steel be identified with a yellow label marked GAS, to avoid confusion (or you could just paint it black). M.R. Return to table of contents
Date: Sat, 23 Oct 2004 06:31:04 -0800 From: "Martin Brungard" <mabrungard at hotmail.com> Subject: Re: PH adjustments John Peed asked for advice regarding acid usage in his brewing practices. He mentioned he was adding acid to reach a specific pH's prior to brewing. As John found out, this is not always the best approach. The need for acidifying is highly dependent on the properties of the water and on the darkness of the grist. I've got the feeling that John didn't need to acidify every beer he brewed. The most important aspect of water that every brewer should understand is Residual Alkalinity (RA). This is an interplay of hardness, alkalinity, and mash grist. I did a quick check on the water supply for Oak Ridge, TN. It is a surface water source, but it flows through carbonate rock terrain. I could not find the important water data like alkalinity and hardness, but would expect that these level are low to moderate. It is possible that this water has a favorable RA to begin with. In this case, acidification for the mash is not needed. If a darker beer is brewed, then acid is definitely not needed. Acid additions are more important with the light colored beers and decreasingly important as the beer darkens. Hardening the brewing water with gypsum doesn't acidify water by itself, but it does reduce the mash pH in conjunction with the grain. The net effect is that the RA of mash is reduced to a more appropriate level. This effect can be counterproductive if the beer being brewed is dark. Then, the natural acidity of the dark grain can push the mash's RA too low. In this case, chalk or sodium bicarbonate may be needed to moderate the dark grain acidity. I have to admit that I've overdone acid additions and I've added acid to dark grists that didn't need it. In either case, the beer is a bit thin and tangy. Acid additions need to be performed with an understanding of its effect. As John found through experimentation, maybe he doesn't need it for every beer. Rob Beck correctly pointed out that phosphoric acid has less flavor than lactic acid. That can help if your water composition requires you to add a lot of acid, but I think that the real problem was that acid additions were not really required for most of the beers John brewed. The first step in figuring out what should be done with your brewing water is to get the water report. You need to call the water utility (or get a water test) and ask for the concentrations of hardness, alkalinity, and major flavor ions. You'll then be able to make a better assessment of what is really needed for brewing. Martin Brungard Tallahassee, FL Return to table of contents
Date: Sun, 24 Oct 2004 09:30:19 -0400 From: Bruce Millington <bmillington at verizon.net> Subject: BONES Bash 2004 Competition The Brewers of the Northeast Section proudly announces the return of the BONES Bash, to be held Saturday, November 6, 2004, at the Nodding Head Brewery & Restaurant in downtown Philadelphia, PA. This will be the first leg of the Delaware Valley Homebrewer of the Year. Entries will be accepted from October 10th thru November 1st, 2004. First place winners will receive prizes. For full details, please go to: www.hbd.org/bones/ We will be using the 1999 BJCP guidelines. We are in desparate need of judges All interested judges and stewards please contact Bruce Millington at bmillington at verizon.net. Judges and stewards are to report by 8:30AM, and begin at 9:00AM. See you at the Bash! Bruce Millington Judge Coordinator Return to table of contents
Date: Sun, 24 Oct 2004 11:16:54 -0400 From: "Dave Burley" <Dave_Burley at charter.net> Subject: serial vs parallel Brewsters: Well, I guess Alan's "exasperation", call it what you will, is not so well placed after all. He agrees with me that glucose does not block the assimilation of fructose, which means to me they are asssimlated in parallel. Which is what I said from the beginning of this discussion with Fredrik. I also pointed out that glucose did block some sugar type assimilation in those modelling discussions with Fredrik.. As to why this is important to brewing, I can't say, except that it is an extension in our mutual interests in brewing and it may be important to someone, someday. But if we are going to discuss it let's get it right in all aspects and help each other understand this complex process in detail. That is the point of the HBD, not to make these scientific issues personal Keep on Brewin' Dave Burley Return to table of contents
Date: Sun, 24 Oct 2004 12:30:57 -0500 From: Bill Velek <billvelek at alltel.net> Subject: Sources of FAN (free amino nitrogen)? Well, unfortunately I missed the FOY, but perhaps someone can still answer these questions about yeast. First, I assume that commercially produced yeast nutrient probably has FAN included in it, probably along with zinc and magnesium, etc. Second, there has been previous discussion some time ago about adding quantities of dried yeast to the boil -- with the really cheap baker's yeast (2 pounds or almost a kilo for a bit more than $3.00 U.S.) being a very economical way to do that. [I realize there is special yeast made with extremely high zinc content, but I'm speaking now of just baker's yeast, or perhaps old packets of regular brewer's yeast.] Questions: 1. Does boiling dried yeast provide FAN, or just minerals? 2. Assuming that boiling dried yeast does provide FAN and minerals that yeast need to grow, how much dried yeast would be the _optimum_ amount to add to the boil when making a 5 U.S. Gallon batch (19 liters)? 3. Besides yeast nutrient, and perhaps dried yeast, is there any other source of FAN that is readily available as an adjunct? Thanks. Bill Velek Return to table of contents
Date: Sun, 24 Oct 2004 12:26:15 -0600 From: Bob Devine <bob.devine at worldnet.att.net> Subject: link of the week - Australian craft brewing Our homebrewing friends in Australia have put together a nice website on homebrewing. Recipes, style histories, and other brewing tidbits are all there. http://oz.craftbrewer.org/ Bob Devine Riverton, UT Return to table of contents
Date: Sun, 24 Oct 2004 14:49:18 -0700 (PDT) From: "Scott D. Braker-Abene" <skotrat at yahoo.com> Subject: New Hop Information Resource Hey Now, I got tired of opening the EVIL PDF files and compiled a DB onto a webpage of a whole bunch of various Hops and their important specifications and such... You can find it here: http://www.skotrat.com/skotrat > Hop Information and here: http://www.brewrats.org > Hop Information I will be cleaning up some of the displays over the next couple weeks... I hope that you use it and find it usefull in your brewing process. C'ya! -Scott ===== "I can't help it... I love being a fart machine" - Heather Braker http://www.skotrat.com/skotrat - Skotrats Beer Page http://www.brewrats.org - BrewRats HomeBrew Club Return to table of contents
Date: Mon, 25 Oct 2004 09:45:58 +1100 From: Grant Family <grants at netspace.net.au> Subject: FOY - Rescuing Old Yeast G'day Drs, About while ago I was bottling a batch of hefeweizen and wanted to reserve some yeast from it. My method was to rinse about 100mL thick yeast slurry in cooled boiled water once or twice, removing as much trub as possible, before leaving it under a 300mL layer of cooled boiled water and storing in the fridge at 1C. The strain was White Labs Hefeweizen (WLP300). I didn't intend on leaving it so long, but today, about 7 months later, I made up a 250mL batch of ~1.035 SG wort with some Wyeast nutrient and pitched it onto the yeast (I poured off the water first). It's in a small plastic bottle and I am squeezing air in and shaking it to introduce as much O2 as possible. It's now fermented out so something is alive. If I wanted to use this yeast, which I probably don't, what would be your suggestions as for how to build up a healthy crop of yeast for pitching? I'm not yet at the plating and culturing stage, and I realize that this would be a good method, but what else can I do? I realize this is probably not anything you'd recommend to the public, but I'd like to know if in desperate times that there's something you can do to save very old yeast. Thanks, Stuart Grant. Hobart, Tasmania, Australia. Return to table of contents
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