HOMEBREW Digest #5233 Wed 26 September 2007

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  re: Effect of dissolved extract on volume (rather geeky) ("-s@adelphia.net")
  Volume Increase ("A.J deLange")
  re: Esters/4VG/N2 (Richard Lynch)
  cleaning counterflow chillers ("Nathan Hirneisen")
  sparging water ("Nick Trubov")

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---------------------------------------------------------------------- Date: Wed, 26 Sep 2007 07:06:56 -0400 From: "-s at adelphia.net" <-s@adelphia.net> Subject: re: Effect of dissolved extract on volume (rather geeky) Bill Pierce recognized the extract has volume and .... > In addition to the dissolved extract increasing the pre-boil volume, > there is another implication for the all-grain brewer. The usual > method of achieving the correct pre-boil volume is to calculate the > target and sparge the grain until it is reached. It's possible (and > relatively common practice) merely to prepare enough hot sparge > water to ensure this occurs. But some brewers (and much of the > brewing software out there) also calculate the total volume of water > needed for both mashing and sparging. > > Now my question is whether the calculations and software account for > the increase in volume due to the dissolved extract. So far as I > can tell, all of the brewing software water-needed calculators do > not. If we use the above example of a target pre-boil volume of > 7.403 gallons, the sparge water volume should be reduced by 0.403 > gallon. Otherwise, unless the brewer measures and monitors the > pre-boil volume, he or she is likely to be oversparging. Everyone since long before Dr.Plato realized that extract impacts volume and density of wort, so this isn't really a surprise. I have no idea what the various software packages assume but ... Sucrose has a density around 1.59 (close to your 100/61.4) and that's an excellent approximation for extract density. The relation as we dissolve extract is not precisely linear, but again quite close. In an all-malt mash you'll extract ~70+% of the grist mass as extract so you roughly add a volume of ~2 Liters per 10 lbs (b*stardized units - no ?). At the same time that 10lbs of grist residue will retain well over 4L of water and a poor bottom end design of the sparge unit may trap a liter or more. Now to confuse matters the hydrolysis of starch to maltose etc will consume water at a rate of roughly 8 or 10 moles of water per 10lbs of grist so another 0.15L - 0.2L goes missing in the sugars and I suspect a similar amount evaporates from a hot mash. The total water req is arrived at in an ad hoc calculation not from first principles. You may well be correct that the software simply makes an calculation: water_volume_in - water_volume_retained = wort_volume and that is clearly wrong by a non-trivial amount as you say. It should be approximately: wv_in - wv_retained + extract_volume = wort_volume ignoring minor correction terms. The "water retained" term is undoubtedly derived by the same people as: wv_retained = wv_in - wort_volume when it should really be: wv_retained = wv_in - wort_volume + extract_volume so this is also incorrect. They derive some figure for gallons of water retained per pound of grist and the extract term is also roughly constant per grist mass, so the error scales with grist mass OK but not for changes in efficiency which are typically small. So this second error does cancel out almost all the error in the first erroneous eqn if you oversimplify the volume calc in this way. For the sake of a concrete example ... Let's assume we have a 10 lb grist and we mash & sparge with 33L of water and we obtain a volume of 28L in the copper. A naive assumption is that we left 5L of water in the grist for 0.5L/lb, but we know that the 28L in the boiler includes abt a 2L volume of extract, so the grist actually retained around 7L of water (0.7L/lb). You can readily see that if we double the grist bill and use the erroneous 0.5L/lb of water retention that we still get the correct volume in the boiler. If OTOH the efficiency dropped in half on the next 10lb batch, then the copper would only collect 27L (1L of extract volume left in the grist). -S Return to table of contents
Date: Wed, 26 Sep 2007 12:29:09 +0000 From: "A.J deLange" <ajdel at cox.net> Subject: Volume Increase The volume increase when making a wort of strength P grams of sugar per 100 grams of wort (i.e. P is the gravity in degrees Plato) is Pct_inc = 0.6*P + 0.00847*P*P (from a 2d order fit to volume data calculated from the ASBC table). Thus, for example, in preparing a 10P wort one would add 10 grams of sugar to 90 grams of water and winds up with 96.327 mL of solution. As the water has a volume of 90.157 mL at 20C this represents a 6.8% increase in the volume of the liquid used. For 12P ("average" strength) the increase is 8.4% and for 20 P it is 15.4%. There are lots of spreadsheets and programs for designing beers and thus many approaches but it seems the most common is to start with how much wort of what strength you want e.g. 5 gallons of 12P wort. The first step would be to convert this to SG = 1.04840 (or you may start with a desired SG in which case the first step is conversion to Plato - both numbers are needed) and calculate that the weight of the wort as 8.33*5*1.04840 = 43.67 lbs of which 12% or 5.2 lbs will be extract and the rest, 38.4 lbs equivalent to 4.6 gallons, will be water. Working in this way the volume increase is never actually calculated but is accounted for. Thus I would say that yes, most of the brewing spreadsheets and programs account for this increase in volume even though most do not calculate it explicitly. When we brew, of course, we are not usually concerned about the amount of water to add to the grains to get the final result knowing full well that water will be retained, that sparge water will have to be used to make up for this, that there will be losses from boiling and so on. Most of us (and I am making an assumption here that may not be warranted) add mash water for desired mash thickness and as required by infustion steps or to maintain mash temperatures, sparge as necessary and top up the boil as necessary to acheive the desired final volume (taking into account that the volume of the wort is 4% greater at near boiling than at room temperature). Return to table of contents
Date: Wed, 26 Sep 2007 09:54:54 -0700 (PDT) From: Richard Lynch <rlny7575 at yahoo.com> Subject: re: Esters/4VG/N2 Just wanted to give a quick "thank you" to Steve Alexander for replying to my question on Yeast and Esters. You provided some very interesting reading, I'll be taking a lot of that into consideration with future brews. Thanks Steve! (and to all others for making HBD such a awesome resource!) -Rich Return to table of contents
Date: Wed, 26 Sep 2007 18:32:05 -0400 From: "Nathan Hirneisen" <cave_nate at hotmail.com> Subject: cleaning counterflow chillers any ideas for cleaning counterflow chillers. the chiller has been getting less effective in its cooling over time. I think it may be getting dirty inside. :-( the chiller is about 10' of 5/16 ID copper with a 5/8 id vinyl water jacket. http://www.hirneisen.com/nate/beer/wort_cool.jpg so far, i have been using a hot b-brite solution to clean followed by a Iodophor santization. my concern is that over time i'm gettign a thin layer of beer stone , etc on the inside of the tube that the b-brite can't clean. this is reducing the heat transfer and a sanitation concern. thanks! -Nate . Return to table of contents
Date: Wed, 26 Sep 2007 21:10:24 -0500 From: "Nick Trubov" <ntrubov at swbell.net> Subject: sparging water >> Date: Tue, 25 Sep 2007 18:26:23 -0400 From Subject: Effect of dissolved extract on volume (rather geeky) I have a brewing spreadsheet, and occasionally I consider adding another bell or whistle to its various sections. ........ << Bill, I took chemistry a LONG time ago but I seem to recall that added sugars or salts or any other substance that dissolves in H2O does not, necessarily, add volume to the pot. And for that reason I am kind of curious if you have actually MEASURED the final volume after sparging? Hydrated moieties do not, necessarily, release their water molecules just because they are dissolved in MORE water. So the water molecules that are attached to the sugars in the malt may have little or NO effect on the final volume of the wort. Have you measured it? I sure would like to know what you find. I do not have the time OR the patience (or even the need) to do the measurements, but I AM curious. Thanks, NT ========================== Nick Trubov and Lorree Madigan and the kids, Corbin and Alex ntrubov at swbell dot net ========================== Return to table of contents
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