HOMEBREW Digest #4862 Wed 05 October 2005


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Contents:
  Analysis of the Continuous sparging process/Viscosity issues (David Harsh)
  Re: Mashout temp and viscosity ("Peter A. Ensminger")
  The Second 2nd Annual Hogtown Brew-Off (Mark Tumarkin)
  racking of p-lambics (KEITH R BUSBY)
  Re: And another thing ! (Jeff Renner)
  Viscosity ("Spencer W. Thomas")
  RE: Subject: efficiency, 1/ batch sparge analysis (Steven Parfitt)
  Sparge efficiency, Mash out and CharlieP ("Dave Burley")
  Re: Wort Chiller Efficiency ("Craig S. Cottingham")
  RE: Wort Chiller Efficiency ("Mike Sharp")
  The Second 2nd Annual Hogtown Brew-Off (Mark Tumarkin)
  Steve Alexander and Steve Jones  re Efficiency and Batch Sparging (Bill Velek)
  Dixie Cup XXII call for judges ("rkolacny")

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---------------------------------------------------------------------- Date: Wed, 5 Oct 2005 00:06:21 -0400 From: David Harsh <dharsh at fuse.net> Subject: Analysis of the Continuous sparging process/Viscosity issues Steve Alexander presents an interesting analysis of a continuous sparging process, but unfortunately, he hasn't modelled the grain bed used in any lauter tun I've ever encountered. Look at the process as described in the model: > "S/2 case": > Step 1: remove S/2 of the original mash water. <snip> > Step 2: After equilibrium, we again replace S/2 of the liquid. > <snip> > Drain: Finally we drain the (M+X-U) volume of liquid What is described here is a sparge process where the grain bed is continuously stirred in order to maintain a uniform concentration within the entire bed; analogous to a stirred tank reactor. Since we're dealing with a fixed bed extraction, operating in unsteady state with varying conditions within the grain bed, the calculations here do not apply. In order to properly model this system (which I think would be a colossal waste of time - I'd rather add the proverbial pound of grain if efficiency is the issue) we need to know some sort of equilibrium relation between the solution and the grain phase; a "sorption isotherm" of some sort. That, with a suitable SWAG with regard to the bed characteristics, might yield useful information. But a) I doubt it and b) I no longer have students to assign such problems to! But I do know that the problem has been set up and solved in Carnahan's Applied Numerical Methods text I used back when Fortran was considered an advanced programming language. If properly modelled, I doubt that the batch process would be found to more efficient. I'll also comment that "efficiency" here could have so many meanings. Taking the time to solve the mathematical model would not count as efficient in my opinion. But I digress. - --------------------------- On mash viscosity- I always assumed that beginning homebrew books were just using improper terminology and that they were referring to wort or extract liquid viscosity, which does decrease with temperature. The references provided in recent digests actually measured the viscosity of the mash itself, and since the grain is stationary during lautering, the mash viscosity would have no effect on the process - the wort viscosity is another matter, however. I didn't find the lack of mash viscosity decrease particularly surprising though - the volume fraction of solids in the mash doesn't change much and that's the primary factor if you look at most correlations for viscosity of suspensions (see Einstein's pioneering work in the field). So why would mash out help efficiency? Liquid viscosity decreases, mass diffusivity increases slightly; thus the Schmidt number decreases and the particle Reynolds number increases (both changes are small). So there wouldn't be much effect on mass transfer coefficient. The only thing left is the equilibrium sorption relationship - the isotherm I mentioned earlier. I would suspect if there's an effect, that's where we'd find it. Dave Harsh Cincinnati, OH Bloatarian Brewing League Return to table of contents
Date: Wed, 05 Oct 2005 00:34:48 -0400 From: "Peter A. Ensminger" <ensmingr at twcny.rr.com> Subject: Re: Mashout temp and viscosity Yes, the effect is negligible! (as noted by -S in http://www.hbd.org/hbd/archive/4859.html#4859-2 ). Figure 2d in J Inst > Brew 111(2): 165-75 is especially relevant. Under the conditions of these experiments, an elevated mashout temperature (78C=172F) has little effect on wort viscosity. Anyone know of an 'el cheapo' viscometer that a poor homebrewer could afford? Cheerio! Peter A. Ensminger Syracuse, NY hbd.org/ensmingr Return to table of contents
Date: Wed, 05 Oct 2005 06:48:26 -0400 From: Mark Tumarkin <tumarkin at hogtownbrewers.org> Subject: The Second 2nd Annual Hogtown Brew-Off The Second Time Around; the "2nd Annual" Hogtown Brew-Off is Back! After the first 2nd Annual Hogtown Brew-Off was canceled last year due to a series of unasked-for hurricanes, we're back bigger than ever! This time, the Second 2nd Annual Hogtown Brew-Off will be held on Saturday, November 19th. We're looking for entries in all BJCP categories of Beer, Mead and Cider. The competition is sanctioned by both the AHA and the BJCP. The entry window opens Monday, Oct. 24th and closes Friday, Nov. 11th. Please check our website at www.hogtownbrewers.org for everything you'll need to enter the Brew-off. We anticipate that this page will be fully functional very soon with on-line registration for judges, electronic entry forms, and the full details of all activities. Check back at the website over the next several weeks for additional information. If you're local, or willing to travel, we're going to need help from you judges to give the entrants the best possible feedback. And as with the 1st Annual Hogtown Brew-Off, we plan to show you a great time! We've got a great new location at the brand new Pontiac Tavern. We'll be holding another One Pub Pub-Crawl to Stubbies. And of course, we'll have another great award ceremony and dinner, with some great prizes and an awesome raffle. So don't miss it - mark your calendars now. Last time, we got some great entries from Florida and around the country. We're looking forward to even more this year. thanks, Mark Tumarkin Please direct any questions to Craig Birkmaier, Competition Organizer Phone: 352 258-2543 Email: craig at pcube.com Or judging questions to Dave Williams, Chief Judge Email: rdavis at gator.net Return to table of contents
Date: Wed, 05 Oct 2005 07:43:48 -0500 From: KEITH R BUSBY <kbusby at wisc.edu> Subject: racking of p-lambics Am I right in assuming that it is undesirable to rack p-lambics (or sour beers using Wyeast Roeselaere) to secondary at all? Keith Keith Busby Douglas Kelly Professor of Medieval French Department of French and Italian The University of Wisconsin 618 Van Hise Hall Madison, WI 53706 (608) 262-3941 (608) 265-3892 (fax) Return to table of contents
Date: Wed, 5 Oct 2005 08:48:01 -0400 From: Jeff Renner <jsrenner at umich.edu> Subject: Re: And another thing ! Mike Dixon of Wake Forest, NC wrote about mash viscosity: > What I do know is that stirring the mash I create at home becomes > easier as > the temperature increases from after dough in to mashout. ... I'm fine > with atrributing it to a lowered viscosity of the mash due to the > higher > temperature. I think it may be due to the mash enzymes acting on the starch and making it less viscous. I see this all the time at a constant temperature when doing a cereal mash with corn meal. It noticeably thins out with time at a constant temperature. Jeff - --- Jeff Renner in Ann Arbor, Michigan USA, jsrennerATumichDOTedu "One never knows, do one?" Fats Waller, American Musician, 1904-1943 ***Please note new address*** Return to table of contents
Date: Wed, 05 Oct 2005 09:07:33 -0400 From: "Spencer W. Thomas" <spencer at spencerwthomas.com> Subject: Viscosity Jeff Renner speculates: >I think it may be due to the mash enzymes acting on the starch and >making it less viscous. I see this all the time at a constant >temperature when doing a cereal mash with corn meal. It noticeably >thins out with time at a constant temperature. > Yup. If you scan the articles that have been thrown around over the last few days, you'll see a significant correlation between viscosity reduction and amylase concentration. A couple of them show an interesting *increase* in viscosity, apparently related to gelatinization of some malt components during the temperature step up to the first amylase rest. This makes it pretty clear that temperature is *not* the major determinant of viscosity in a mash. =S Return to table of contents
Date: Wed, 5 Oct 2005 06:56:09 -0700 (PDT) From: Steven Parfitt <thegimp98 at yahoo.com> Subject: RE: Subject: efficiency, 1/ batch sparge analysis steve does a nice job of laying out the analysis of batch vs fly (or imcremental) sparging. <Well my face may red, but it's others acting like <baboons here. Continuous sparge is LESS efficient <than batch in the general case. <But it requires some detailed analysis to see why. ...snip... <Now all mashes start with a volume of mash water M, <and we assume that after the relatively long mash <period that the extract both in and outside the grist <are near equilibrium. Ah-Ha! But are they really near equilibrium? How long does it take to reach this equilibrium? Is a 40 minute mash followied by a 20 minute drain, and 20 minute wait before draining the second sparge enough? If not, then the equations need to be driven by the differnece between in extract solution and not in solution in which case fly sparge creates a greater differnetial to drive the equations. Therefore, IF one waits long enough to reach equilibrium batch sparge will be more efficent. But fly sparging may be more efficient if sparging is done before equilibrium is achieved. Steven, -75 XLCH- Ironhead Nano-Brewery http://thegimp.8k.com Johnson City, TN [422.7, 169.2] Rennerian "There is no such thing as gravity, the earth sucks." Wings Whiplash - 1968 Return to table of contents
Date: Wed, 5 Oct 2005 09:58:48 -0400 From: "Dave Burley" <Dave_Burley at charter.net> Subject: Sparge efficiency, Mash out and CharlieP Brewsters: SteveA insists that batch sparging is more efficient than continuous sparging in terms of removing soluble sugar and expends several pages with his examples to try to prove it, denying Chemical and Chemical Engineering concepts to the contrary. Here is a simple way to think about it. At the end of the sparge in either case, the wort coming from the sparge has a certain specific gravity. We know for sure the wort inside the grain is probably more than the wort but If we make the simple assumption (not really true) that the specific gravity of the wort inside the grain is the same as the wort outside the grain, then we can see that with the batch sparge, in which the final sparge has a specific gravity of say 1.030 or whatever, and the continuous sparge has a value of 1.006 or less, there will be a clear difference in the amount of sugar left in the grain. I leave it up to the student to calculate the amount of sugar left in the grain in both cases, given that after the mash about a pint (I think) of water is contained in each dry pound of malt. Clearly the lower specific gravity at the end of the sparge, in the case of the continuous sparge, indicates the better efficiency of this process since there is less sugar absorbed in the remaining brewer's grains. Now go back and examine the original assumption and you will see an even bigger difference, since the continuous sparge allows the establishment of an equilibrium of the wort in the grain with the sparge water and the much shorter time of the batch sparge likely does not, as studies on the efficiency of different rates of continuous sparge would indicate. Faster sparges are less efficient. When you realize that in the continuous sparge, the exiting specific gravity is the highest value in the whole column of grain and then go back and re-examine these cases, it becomes even clearer. Try the experiment I suggested in which these two sparging methods are done with the same batch. Then add the same <volume> (say 4 cups) of drained brewer's grains to the same amount of water (maybe a pint to cover) and allow it to stand overnight. Measure the sugar concentration of the water in each case with Clinitest and you will find the batch sparge will have the higher concentration, proving it is less efficient. - --------------- Steve, the reason for the temperature boost at the end of the mash (aka mashout) has nothing to do with the viscosity change (which is in fact lower at the higher temperature, as we both now agree) but is done to clean up any starch - avoiding a "Blue mash", as the Germans call it, and to stop any enzyme action. Co-incidentallly, the lower viscosity of the wort will allow faster draining and most likely a faster establishment of equilibrium at the higher temperature, and, although I have never seen the wort viscosity given as the reason for the mashout, I agree with you a lower mash viscosity is not the raison d'etre. Pardon my French. - --------------- Steve, I wasn't denigrating CharlieP by using his own description of himself (which I find quite amusing as I do some of his other clever attempts at humor), just pointing out the origin of the "add another pound of malt" and the state of the art when CharlieP wrote that. I doubt that today he would say that, just like he now knows how to do an iodine test including the grain and recommends longer mashes and not to spray hot wort through the air. In fact, I think CharlieP has done a great thing for the Home Brewing industry in the US and around the world and his position and big paycheck (clearly more than a grade school teacher) shows people appreciate that. - -------------- And you couldn't see me smiling when I wrote that "graininess" flavor thing, just to get your back up. {8^) I do find, however, that continuous sparging does give a more complex flavor to the beer, compared to batch sparged and malt extract beers. Whether or not a bunch of other unknown people with other unknown preferences and experience (without commenting on the difference in complexity) prefer it or not is irrelevant. Keep on Brewin' Dave Burley Return to table of contents
Date: Wed, 5 Oct 2005 10:33:35 -0500 From: "Craig S. Cottingham" <craig at cottingham.net> Subject: Re: Wort Chiller Efficiency On Oct 4, 2005, at 07:29, Pete Limosani <peteLimo at comcast.net> wrote: > I'm trying cut down on my water usage during a brew session. > > I boil about 7.5 gallons down to 6 and use an immersion chiller to > cool it. > It generally takes 20-25 minutes to get from boiling to 70-75*. > > When I first start cooling I open up the valve full throttle and the > water > escaping the chiller is steaming. The difference in temperature > between water > entering the chiller and exiting the chiller is great. As the wort > cools down, > the difference in temperature closes and it takes longer to drop that > next > degree. > > As the difference in temperature decreases, I am tempted to slow the > amount > of water running through the chiller to save water. My thinking is > that less > water will be used, but the water may extract a couple more degrees > while > it is travelling. > > Is my logic flawed? At first, I thought this was going to be easy to answer. Then I thought about it some more, and realized it was more difficult. Then I thought some more, and I realized it was a *lot* more difficult. A gut feeling became algebra, which became differential equations. Too many years (and beers) have passed since college; I don't have the math muscles I used to. So it's back to the gut feeling. > Will I use less water over the whole cooling cycle by keeping it wide > open? I'm confident answering "no" to this. Heat transfer is a function of temperature differential and time. The greater the difference in temperature between the wort and the cooling water, the faster heat will flow from one to the other. The *quantity* of heat that's transferred is this rate times the amount of time that the cooling water is in contact with the wort. Twenty feet of 3/8" OD copper tubing has an interior volume of about 0.075 gallons (a little less than 1 1/4 C). My kitchen faucet can fill a gallon jug in a little over 30 seconds (for a flow rate of about 2 gal/min), and I expect without hard evidence that my garden hose could do it faster. At 2 gal/min, water goes from one end of your immersion chiller to the other in about 2 seconds. When the wort has just finished boiling, that's enough time to soak up a fair amount of heat, but as the wort temperature drops, less and less heat flows in that 2 seconds. You can't increase the rate of heat transfer -- in fact, it's going down, because the temperature differential is going down -- so you have to increase the amount of time heat has to transfer. In other words, > Or will I use less water by slowing the flow and waiting a little > longer? Yes. > How do I find the best balance between the rate of flow and the rate > of heat > extraction? This is where it gets interesting. We could use math -- okay, maybe you could use math; I can't, because I've forgotten the necessary math skills. :-) So let's try to approach it empirically. Since heat flows only when there's a difference in temperature, the cooling water will never get hotter than the wort. But if the temperature of the cooling water at the exit is lower than the temperature of the wort, we're leaving money on the table; there was a little more potential for heat transfer. What we should be aiming for is for the exit temperature of the cooling water to be the same as the wort temperature. You could set up thermometers in the wort and the exit of the chiller, and monitor them closely, continuously reducing the flow rate of the cooling water... or you could relax and drink whatever you made the last time you brewed. Start your cooling water full bore. As you clean up, occasionally feel the water coming out of the chiller; as soon as you notice it feels cool or tepid instead of warm or hot, turn the water down. Hope this helps. - -- Craig S. Cottingham craig at cottingham.net OpenPGP key available from: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x7977F79C Return to table of contents
Date: Wed, 5 Oct 2005 09:13:13 -0700 From: "Mike Sharp" <rdcpro at hotmail.com> Subject: RE: Wort Chiller Efficiency Pete Limosani asks about Wort Chiller Efficiency: "I'm trying cut down on my water usage during a brew session." If minimizing water use while chilling is important, use a counterflow chiller. It's much more efficient than an immersion chiller (though a bit more of a pain to use). Regards, Mike Sharp Return to table of contents
Date: Wed, 05 Oct 2005 13:02:31 -0400 From: Mark Tumarkin <tumarkin at hogtownbrewers.org> Subject: The Second 2nd Annual Hogtown Brew-Off The Second Time Around; the "2nd Annual" Hogtown Brew-off is back!! After the first 2nd Annual Hogtown Brew-off was cancelled last year due a series of unasked-for hurricanes, we're back bigger than ever! This time the Second 2nd Annual Hogtown Brew-off will be held on Saturday, November 19th. We're looking for entries in all BJCP beer, cider & mead categories. The event is sanctioned by both the BJCP & AHA. The entry window opens Monday, Oct 24th & closes Friday, Nov 11th. Please check our website at www.hogtownbrewers.org for all info concerning the Brew-off. We anticipate that this page will be fully functional very soon with electronic entry forms, online judge-entry, and full details on all activities. Check back at the website over the next several weeks for addtional info. If you're local, or willing to travel, we're going to need help from you judges to give the entrants the best possible feedback. And as with the 1st Annual Hogtown Brew-off, we plan to show you a great time! We've got a great new location at the brand new Pontiac Tavern. We'll be holding another One Pub Pub-Crawl to Stubbies. And of course, we'll have another great award ceremony & dinner, with some great prizes and an awesome raffle. So don't miss it - mark your calendars now. Las time, we got some great entries from Florida & around the country. We're looking forward to even more this year. thanks, Mark Tumarkin Please direct any questions to Craig Birkmaier, Competition Organizer craig at pcube or to Dave Williams, Chief Judge at rdavis at gator.net Return to table of contents
Date: Wed, 05 Oct 2005 13:18:09 -0500 From: Bill Velek <billvelek at alltel.net> Subject: Steve Alexander and Steve Jones re Efficiency and Batch Sparging Steve Alexander: those were outstanding posts you wrote containing the mathematical proof that batch sparging is actually more efficient than fly sparging. Thank you. I do have one question, though. Early in your first post, you stated: "Let's say we have X volume units of soluble extract (when in solution) and let's just estimate that this has some density in solution around 1.55 times that of water - close to mash extract, so the mass of extract is then X * 1.55." Was that extraneous info, or does it relate in some way to the math you have done? No problem if it's extraneous, except that it initially caused me some slight confusion as I looked for it later in your post. I say that because the "1.55" constant never appears again anywhere in your math, nor can I find where you have substituted it with a variable. Am I missing something? - --- Steve Jones: until Steve Alexander posted his mathematical proof, I was very much persuaded by the apparent logic of your post. After looking at his math, I felt compelled to sort out the logic to try to figure out why they didn't seem to agree. I _think_ I have it figured out now. I think that all of your premises were/are correct, but I think that you and I both jumped to the wrong conclusion. While it is no doubt true that the SG of the final 'batch' will always be higher than the SG of the final runnings on the fly (continuous sparging), that doesn't logically mean that there is more sugar left behind in the grain bed, like I think we each assumed. I think the answer is that we should not consider the SG of the final batch that is _drained_, but rather we should consider what would be the SG of the tun when it is refilled with the same volume as remains when the fly sparging is stopped. I think, based on the math, that we would find that when it is diluted (as if we were planning to do a third batch sparge), that the SG of the 3rd batch would be lower than the SG of what remains at the end of a fly sparge. I hope I'm making some sense here. - --- Thanks again to everyone; this was all very interesting and thought provoking, but now I have a couple of follow-up questions: in another brewing forum, I was advised of the importance of "floating" the grain bed in the tun by minimizing stirring in order to allow air to remain trapped in the grist. But it is my understanding that when batch sparging, new sparge water is stirred into the grain bed to dissolve remaining sugars. Because of the stirring, I assume that the bed does not float, per se; is that true, and does it matter when batch sparging? If the bed doesn't float, are there more stuck mashes associated with batch sparging? Thanks for any further info. Bill Velek Return to table of contents
Date: Wed, 5 Oct 2005 15:59:11 -0500 From: "rkolacny" <rkolacny at mail.ev1.net> Subject: Dixie Cup XXII call for judges ATTENTION: Beer Judges Needed!!! It is Dixie Cup time again! and we will start judging the Dixie Cup XXII entries soon. Please, come be a part of Dixie Cup and help us judge. We need beer judges of all skill levels to come and help out. Don't worry if you are not BJCP ranked. We will either put you on a panel with experienced judges or use you as a steward. Everyone can be a beer judge!!! Here is the judging schedule: 10/16 First round judging at Saint Arnold Brewing Company from 9 AM to 4 PM. 10/18 First round judging continues at Saint Arnold Brewing Company from 6 PM to 10 PM. (This judging session is contingent upon progress made on Sunday). 10/21 First round judging continues Noon - 10/22 Second round judging Noon - That's it! Please come out and give generously! Na zdravi (to your health or cheers!) Rob Kolacny Dixie Cup Coordinator http://www.crunchyfrog.net/dixiecup/ Secondary Fermenter Foam Rangers www.foamrangers.com rkolacny at ev1.net 979 532 8056 wk 979 532 1932 hm 979 533 1173 cell Return to table of contents
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