HOMEBREW Digest #5508 Thu 19 February 2009

[Prev HBD] [Index] [Next HBD] [Back]

		Digest Janitor: pbabcock at hbd.org


                 Sponsor The Home Brew Digest!
     Visit http://www.hbd.org/sponsorhbd.shtml to learn how
    Support those who support you! Visit our sponsor's site!
********** Also visit http://hbd.org/hbdsponsors.html *********

DONATE to the Home Brew Digest. Home Brew Digest, Inc. is a 
501(c)3 not-for-profit organization under IRS rules (see the
FAQ at http://hbd.org for details of this status). Donations
can be made by check to Home Brew Digest mailed to:

HBD Server Fund
PO Box 871309
Canton Township, MI 48187-6309

or by paypal to address serverfund@hbd.org. DONATIONS of $250 
or more will be provided with receipts. SPONSORSHIPS of any 
amount are considered paid advertisement, and may be deductible
under IRS rules as a business expense. Please consult with your 
tax professional, then see http://hbd.org for available 
sponsorship opportunities.

  Re: Heat calculations and thermal mass (Matt)
  Lansing Water ("A.J deLange")
  Thermal Mass of Mash Tuns ("A.J deLange")
  Re: Thermal Mass (Joe Walts)
  Re: Heat calculations and thermal mass (Calvin Perilloux)
  Boston Homebrew Competition - Call for Judges (Eric Wooten)
  Thermal Mass (Kevin Elsken)

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * The HBD Logo Store is now open! * * http://www.hbd.org/store.html * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Beer is our obsession and we're late for therapy! * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * NOTE: With the economy as it is, the HBD is struggling to meet its meager operating expenses of approximately $3400 per year. If less than half of those currently directly subscribed to the HBD sent in a mere $5.00, the HBD would be able to easily meet its annual expenses, with room to spare for next year. Please consider it. As always, donors and donations are publicly acknowledged and accounted for on the HBD web page. THank you 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. LOOKING TO BUY OR SELL USED EQUIPMENT? Please do not post about it here. Go instead to http://homebrewfleamarket.com and post a free ad there. 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@hbd.org or read the HBD FAQ at http://hbd.org. JANITORs on duty: Pat Babcock (pbabcock at hbd dot org), Jason Henning, and Spencer Thomas
---------------------------------------------------------------------- Date: Wed, 18 Feb 2009 20:42:02 -0800 (PST) From: Matt <baumssl27 at yahoo.com> Subject: Re: Heat calculations and thermal mass > I am wondering what is the cause of this discrepancy. Slaking heat! The hydration of malt involves chemical reactions that release significant amounts of heat. Thus it *appears* to require less heat than expected to bring the cold mash tun up to mash temp. For not very detailed details, take a look at Malting and Brewing Science by Briggs and Shanks on google books, and search for "slaking heat." A 5F temp shift is indicated under pretty standard conditions. For single infusion mashes at 150F at 1.5 qt/lb in my system, the two effects cancel well enough that I routinely ignore them both and hit mash temps to within 1F (and I don't measure my strike water volume with much care, either). Unfortunately it's not always so easy. Mash tun thermal mass and slaking heat have different effects under different mash conditions and a single "fudge factor" can't account for both of them at once. More calculation complexity is needed to account for them well. Further, theoretical values are not easy to come by and at least for me the numbers in the above reference don't work well (half works much better). This is not surprising given the complex nature of the reaction, different malt grinds, many variables, etc. I think one would have to be very lucky to arrive at a formula to predict mash temps to within, say, 1F on a given system without some fairly thorough observations of different mashes on that system. Matt Return to table of contents
Date: Thu, 19 Feb 2009 08:08:02 -0500 From: "A.J deLange" <ajdel at cox.net> Subject: Lansing Water The water in question has Ca: 20, Mg: 9.7, Na: 44, SO4: 70; Cl: 46, HCO3 42.1 all assumed to be mg/L which is a reasonable assumption as those units cause the profile charge imbalance to be only 4% which is pretty good i.e. the profile is consistent (I assumed pH 7.5 at 20 C). This water is not very hard (total hardness 89.8 ppm as CaCO3 of which 37 is temporary) nor very alkaline (37 ppm as CaCO3) with a very modest Residual Alkalinity of 17 ppm as CaCO3 from which an upward pH shift (relative to distilled water) of only 0.03 is to be expected. IOW no action should be required to set mash pH with base malts and even a small amount of colored malt should result in a good value. The water is well undersaturated with respect to calcium carbonate i.e. no calcium carbonate would be expected to precipitate upon standing but somewhat over saturated with respect to CO2 so that gas can be expected to escape over time with a gradual increase in pH. It has fair amounts of sulfate and chloride so beers made with it may have a round, full bodies character and hops will be perceived as somewhat dry and a bit rough. You couldn't use this water for delicate continental lagers or similar beers because of the sulfate. There may be a mineral crispness to beers made with this water and perhaps a hint of saltiness (does it taste salty from the tap?). Adding gypsum at the rate of 0.5 gram/liter (12.5 grams in 25 L) obviously increases the sulfate (to 349 mg/L) and the calcium hardness (total to 380 while temporary hardness stays the same as the hardness exceeds the alkalinity) dramatically. The extra calcium decreases the residual alkalinity to -67 ppm as CaCO3 which predicts a decrease of mash pH (relative to a distilled water mash) of 0.11 pH. Because a lot of doubly charged ions (Ca++, SO4--)have been added the ionic strength changes enough to induce a small pH shift in the water itself (about 0.02 pH in the acid direction) but the water is still undersaturated (saturation pH is 7.83) with respect to calcium carbonate because the alkalinity is so low below 1 mEq/L (50 ppm). Adding gypsum does not change alkalinity. It, therefore, not likely that boiling will cause anything to precipitate (as it would in harder waters with higher alkalinity). Boiling, as a rule of thumb, reduces hard, carbonate water alkalinity down to about 1 mEq/L (50 ppm as CaCO3) and this water is below that (even post treatment). All the information extracted from the basic water report presented here came from my water analysis spreadsheet which is at http:/www.wetnewf.org/Brewing_articles/BURP_OCT08 IOW, you can get all this info yourself if you are so inclined though expect to spend some time trying to figure the thing out. There are extensive instructions but I know this is complex stuff (based on how many years it has taken me to get this far). A. J. Return to table of contents
Date: Thu, 19 Feb 2009 09:17:20 -0500 From: "A.J deLange" <ajdel at cox.net> Subject: Thermal Mass of Mash Tuns It's been a while since we did the algorithms for ProMash so I'd have to go back and look at some notes but as I recall the big problem with pouring hot water into a tun at room temperature is that the water loses so much heat in the transfer that it throws the calculation off. Thinking it over it seems a better way might be to fill the tun with a known mass of water at room temperature, heat the water to a few degrees above room temperature, let it equilibrate (stand for an hour or so with occasional stirring) or put some hot water in the tun and let it stand, with stirring, until its temperature is a few degrees above room temperature and then add a known mass of water at room temperature. This prevents heat loss from either the water in the tun (even if it's a few degrees above ambient some heat will be lost but the rate of loss is proportional to the temperature difference) or the water added. Note that I say known "mass" of water. Probably the best way to do this would be to put the tun on a scale. When its empty you have its weight (not that you really need that) but you can tare it to measure the mass of warm water and then take the difference after you add the cooler water. I'm talking mass here because the volume of a given mass of water does change appreciably with temperature (several percent). Another thing to be aware of is that the heat capacity of water does change somewhat as a function of temperature. I handled this relatively simply by computing an average over any given temperature range i.e. if you go from T0 to T1<T0 when you add cold water the average heat capacity is simply (1/(T0- T1))*Integral_from_T1_to_T0[Cp(T) dT)]. You can find Cp(T) in handbooks, Wikipedia etc. Errors induced by ignoring this will be much smaller than errors induced by ignoring density changes and being unable to control heat losses. A.J. Return to table of contents
Date: Thu, 19 Feb 2009 08:33:03 -0600 From: Joe Walts <jwalts at gmail.com> Subject: Re: Thermal Mass Hey Bill, just a couple of quick and dirty guesses here: First off, you're not raising the temperature of your entire mash tun to the desired mash temperature. Instead, you're creating a gradient through the vessel walls where the inside surfaces are at the mash temperature and the outside surfaces are at ambient temperature. The latter scenario requires less heat energy from the strike water, Unless you model the gradient in your heat capacity calculation, your experiment will result in a lower thermal mass. The second complication is the time. How long does it take the system become stable, i.e. to where you're slowly losing heat to the atmosphere instead of to the vessel itself? I have no idea, so I just overheat my strike water by 10 degrees, dump it in the mash tun and wait to add the grain until the water cools to my desired strike temperature (which doesn't include the thermal mass of the mash tun in its calculation). Joe Return to table of contents
Date: Thu, 19 Feb 2009 06:56:39 -0800 (PST) From: Calvin Perilloux <calvinperilloux at yahoo.com> Subject: Re: Heat calculations and thermal mass Regarding Bill Pierce's formulas for thermal mash... That's good research for an English major, Bill! ;-) > 0.119*32.92 = 3.92 > Unfortunately this is in conflict with the value > I arrived at (1.918 lbs.) based on my formula and > experiment with hot water as described above. You are now into the scientific area best explained by this quote: "Well, that's great in practice, but does it work in theory?" Without delving too much into the formulas, and not having my trusty CRC handbook nearby anyway, I'll highlight a few things to consider, not only for your setup but for others: The structure of your vessel can have some significant effect. In the case of a converted keg, the heavy rings top and bottom are to some extent isolated from the rest of the body. Sure, it's thermally attached as one piece of stainless, but my guess is that the conduction might not be great enough to rapidly heat those. That would leave the body of the keg absorbing most of the heat and not the edges. So in your empirical tests it could show a lower thermal heat because those outer areas are not being heated (as much). In other cases, such as people using stainless pots for mash tuns, the handles are a minimal factor (as above), but keep in mind that there is often an aluminum layer in the base (for heat distribution because stainless is such a poor heat conductor), and this might make it hard to get the results just right on paper -- do you know how much the alu-sandwich inside there weighs? There is also the heat loss that you encounter in bringing the hot water to the mash tun and pouring it. I find that this is not that large but definitely not insignificant. In my own opinion, the very best way to do this is to just do the empirical work on your own system and use that number. When you do that, the heat loss, mixed-metal proportion, and structural features will all be accounted for in your end result. Calvin Perilloux Middletown, Maryland, USA Return to table of contents
Date: Thu, 19 Feb 2009 10:19:58 -0500 From: Eric Wooten <ecwooten at gmail.com> Subject: Boston Homebrew Competition - Call for Judges The 14th Boston Homebrew Competition is coming up on Saturday, February 28th. It will be held at the law offices of Holland and Knight, located in the Back Bay region of Boston about 2 blocks from the Public Garden (Back Bay and Arlington Stations are within easy walking distance for those traveling by MBTA). Preliminary counts yield a total of 271 entries this year (the entry window is now closed). We are still looking for both experienced and novice judges and stewards to help with this years competition. If you are able to help with judging or stewarding, please fill out the judge registration form at http://bhc.wort.org/judgereg.shtml. Further details about the judging process can be found at: http://bhc.wort.org/judgeinfo.shtml. Although the competition site is easily accessible by the T and Commuter Rail, on site parking is available and the competition will cover parking fees for all individuals who register in advance. Important Note: As the competition will be held in a secured building, pre-registration to judge or steward is required. Building security needs a list of people to provide to their check-in desk in advance of the competition. If you have already signed up to help out: thanks in advance for helping us put on another great competition; Mark Irwin, the judging coordinator for BHC 14, will be contacting you soon with the final details. If any of you have any questions please do not hesitate to contact us. Eric Wooten, Competition Organizer (organizer at wort.org) Mark Irwin, Judging Coordinator (irwin at wort.org) Wade Hicks, Entry Organizer (treasurer at wort.org) Return to table of contents
Date: Thu, 19 Feb 2009 21:17:27 -0500 From: Kevin Elsken <littleboybrew at verizon.net> Subject: Thermal Mass Bill, First of all, for goodness sakes man, come over to the dark side and just use the metric system! It is just so much better and easier. Anyway, I have gone through many turns trying to hammer out thermal mass values to give consistent mash temperatures. I suspect won't be the first to mention that your calculation implies your entire mash tun was heated from 70 def F to 157 deg F. In truth, only a portion of the 32 lb+ tun is actually increasing in temperature from 70 to 157. The converted kegs have heavy rolled rings around the top and bottom that most certainly did not change temperature that much. According to the quick calculations I made, the water lost about 176 kJ, but it would require almost 361 kJ to raise your mash tun from 70 to 157 F. Incidentally, insulated coolers are primarily polyurethane foam, which has a heat capacity of about 1.5 kJ/kg. The trick to the calculation with an insulated cooler is that due to the excellent insulation value of the cooler, the outside remains at ambient temperature, so the actual temperature rise is only about one half the difference between the inside and outside of the cooler. Kevin Elsken Little Boy Brewery Upper Saint Clair, PA Return to table of contents
[Prev HBD] [Index] [Next HBD] [Back]
HTML-ized on 02/19/09, by HBD2HTML v1.2 by KFL
webmaster@hbd.org, KFL, 10/9/96