HOMEBREW Digest #4428 Wed 17 December 2003


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	FORUM ON BEER, HOMEBREWING, AND RELATED ISSUES
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Contents:
  Scorched a direct fired mash ("Urban, Michael J, WCITS")
  Re: How to throttle magnetic pump? ("Gary Smith")
  beer in Freiburg & Nurnberg (Germany) ("Peter A. Ensminger")
  er: Pediococcus ("-S")
  Re: RIMS temperature control ("Gary Smith")
  Beersicle ("Dave Larsen")
  re: RIMS Temperature Control ("-S")
  RE: RIMS temperature control (Steve Jones)
  Re: Rogue Chocolate Stout (R.A.)" <rbarrett@ford.com>
  Karlsruhe (Jim Busch)
  PID Control ("Todd M. Snyder")
  re: Transporting Kegged Beer ("C.D. Pritchard")
  Yeast Cannibalism? ("Gregory D. Morris")
  re: How to throttle magnetic pump? ("C.D. Pritchard")
  RE: Throttling Outflow of Magnetic Pump ("Parker Dutro")
  Beer on a German Tour ("Bob Speights")
  RIMS thermal density ("Chad Stevens")
  5 gallons per minute ("Ronald La Borde")
  Re: PID Control ("Mike Sharp")
  natural chocolate flavoring (Marc Sedam)
  creating clear canned wort ("Rob Dewhirst")
  Re: How to throttle magnetic pump? ("David")
  Re: RIMS Temperature Control (David Towson)
  Re: RIMS Ramp Rates, PID Controlled etc (Dion Hollenbeck)

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---------------------------------------------------------------------- Date: Mon, 15 Dec 2003 19:07:24 -0500 From: "Urban, Michael J, WCITS" <mjurban at att.com> Subject: Scorched a direct fired mash Beer Geeks - My brewing partner and I just finished our first all grain brew. Everything went well, except we managed to scorch the bottom of our mash tun adding direct heat for the temperature steps. The end effect on the flavor is yet to be determined, although the wort tasted pretty darn good. I've since done some searching in the archives, and the good news is that at least we're not alone, as this seems to be a fairly common problem with direct fired mash tuns. The bad news is that I didn't find a silver bullet; there wasn't any secret which would allow us to avoid the same situation in the future. The solution seems to be to find a way to avoid direct heat in the mash steps. I've since given some thought to the alternatives. Playing around with Promash tells me I can do all the steps with infusions if I dough in with a stiff mash (~.75 qt./lb.), and use infusion temps of 210 oF. Since the mash tun is not insulated (yet), we may have to add small amounts of direct heat to maintain temp, but the ramps I think we can handle with infusions, and still end up with a final ration of ~1.85 qts./lb. So after all this rambling, here's the question: Are we in danger of local enzyme denaturing by adding water at 210 oF.? I know we'll have to be stirring pretty vigorously, but still the temp gradient is going to be pronounced until everything stabilizes. Also, is there any advantage (or disadvantage) to adding the infusion through the outlet, thus introducing the water at the bottom of the mash rather than the top. Since heat rises, I thought it might be better to reach a stable temp that way, and also to avoid any cooling at the surface. Advice would be appreciated. Michael Urban Winter Springs, FL [952.4, 170.5] Return to table of contents
Date: Tue, 16 Dec 2003 00:58:46 -0600 From: "Gary Smith" <mandolinist at ameritech.net> Subject: Re: How to throttle magnetic pump? Brendan asks how to get or not to get pumped up > I've got a new magnetic pump (from morebeer.com) and was wondering if > the best way to throttle the flow is to (1) restrict flow output or > (2) use a dimmer switch to reduce power to motor. I understand that > reducing motor speed would also slow the cooling fan, but I guess I > could cool externally. Does outflow restriction have any negative > impact on pump/motor? Thanks in advance. With a magnetic pump you want to throttle the output. If you throttle the input you can cause cavitation (spinning in place) and this will cause bubbling which will severely affect the pumping. At high enough temps maybe even a problem with hot side aeration. With peristaltic pumps you must throttle the intake side for with an obstructon on the output you will end up with a burst output line. Gary Gary Smith CQ DX de KA1J http://musician.dyndns.org Most of us know how to say nothing--few of us know when. Return to table of contents
Date: Tue, 16 Dec 2003 02:21:25 -0500 From: "Peter A. Ensminger" <ensmingr at twcny.rr.com> Subject: beer in Freiburg & Nurnberg (Germany) Hi Stan, I lived in Freiburg from 1989-1991 and visited again in 1996. Hausbrauerei Feierling, <http://www.inselbrauerei.de/>, was great back then. Now? There's also Martin's Brau (another Hausbrauerei). Their beer was less impressive, but their menu was better. My memories of Nurnburg are a bit fuzzy, but this region is known for its "smoke beer". I would also suggest a visit to the Weizenbeerglasmuseum <http://museumsvielfalt-nuernberg.de/weizenbierglasmuseum/> in Nurnberg. Cheerio! Peter A. Ensminger Syracuse, NY - ----- I have very limited internet access right now, so I haven't been able to check the archives. Sorry. Soon I'll be driving from Prague to Nurnberg (spending a couple of nights) and then to Freiburg (extreme western Germany, very close to French border)--I'm picking up my nephew who lives with his mother in Freiburg and bringing him back to Tabor for the holidays with his father. Any recommendations for beer drinking along this route? Thanks! Stan Burnett Tabor, CZ Return to table of contents
Date: Tue, 16 Dec 2003 02:33:54 -0500 From: "-S" <-s at adelphia.net> Subject: er: Pediococcus A.J deLange writes ... >The aptly named P. damnosus is easily recognized under the microscope. >It looks like pairs or quads of little dots. But so do all Pedios ! Aerococci, Amaricocci are tetrad formers as well and it's likely some other lactos are.. Sarcina form 2x2x2 cubes which can be difficult to distinguish. Further the list of Pedios include ... P. claussen, P. acidilactici, P. claussenii, P. damnosus, P. dextrinicus, P. halophilus, P. inopinatus, P. parvulus, P. pentosaceus and P. urinaeequi - all tetrad formers and several known brewery infections among these. Practically it doesn't matter, but they can't be identified accurately without a sequence of distinguishing tests or by genetic or antigen means. -S Return to table of contents
Date: Tue, 16 Dec 2003 02:06:06 -0600 From: "Gary Smith" <mandolinist at ameritech.net> Subject: Re: RIMS temperature control On 16 Dec 2003 at 1:35, post at hbd.org wrote: Todd wants to know about RIMS flow rates > But 5 gpm seems really really high to me. How can you > get that much > flow thru the grainbed without compressing it? What > flowrate do > other RIMSers use? > > Gary says that the flow is higher than 0.25-0.5 gpm, but > gives no > number for what he uses, can you post your RIMS > flowrate, Gary? I > also agree with Gary about the carmelization myth. > After making > maple I thought I'd mentioned my flow rate and looking back I did use it in an example but didn't specify it as being my existing rate. My rate is similar to Dion's and is also at around five gallons per minute. I have yet to have a stuck mash even once (lucky? Maybe...) I do start off with the output at zero and over the space of a minute open it fully and never slow that down throughout the cycles. I have a Sanke mash-tun and a SABCO false bottom and the grain at the end of mashing is 8" from the top of the Mash-Tun so it is a very full bed of grain I'm mashing through. My last wheat beer had a grain bill of 23 pounds and of that 13 was wheat. That's more than 50% wheat and I had a beautiful flow. Not stirring has certain advantages and the wheat did not turn to chewing gum in the least nor did it cause any compaction whatsoever. I haven't actually timed it with a stopwatch but to fill my boil kettle from the mash tun when I don't sparge takes certainly takes no more than three minutes. All the sanke's are on the same single tier and the boil kettle is filling through the siphon at the bottom of the keg & going through the ball valve so it's pumping against the increasing weight of the boil kettle mash. With the RIMS, the flow is not against the back-pressure of the liquid, it schleps in through the top of the mash-tun with no added pressure to slow it down. I use two pumps in my system but both are identical in flow rates. I mention this to give you a real time example of the rate of flow. Bill at what was Moving Brews insisted I put the thermocouple as close to the the heater output as possible and indeed my probe tip is less than 2" from the proximal end of the heating element. Since the controler is set to turn off at the set temp and as the heat is not on steadily as the temperature approaches the set point, there is no overshoot of temperature. (Within five degrees or so of the set-point the controler pulses on & off with more off the closer to set point until it is 100% off at set point) below that temp the controler is essentially 100% on. As my entire mash-tun (top, bottom & sides), rims chamber and connecting hoses are insulated with double layers of metalized bubble wrap or cell foam on the hoses, it is extremely efficient. I can put my hand anywhere on the mash tun when it's at 170F and it is only mildly warm to the touch. The controler does not turn on very often once the set temp has been achieved. Overshooting the temperature can not happen if you have your rims set up this way. Cheers, Return to table of contents
Date: Tue, 16 Dec 2003 09:10:45 +0000 From: "Dave Larsen" <hunahpumonkey at hotmail.com> Subject: Beersicle So I'm trying my first lager: a Marzen. I'm lagering it in my serving fridge in a corny. In the keg right next to it is the last gallon of a California Common I was saving for a small competition in a month or so. After a couple months of lagering I decided the rack the Marzen and put it on the gas to carbonate. All went very well -- well except for one thing. For some reason I tapped on the California Common only to find out that it was frozen solid. Imagine that, two kegs of beer side by side, one completely frozen, the other not. I'm guessing that it has been frozen the whole time I've been lagering the Marzen. It must have been at exactly the right temp in relation to the respective alcohol contents to do that. The temp on the thermometer I have in the fridge read 31 degrees F the whole time. I've since raised it to about 35 degrees F. So now comes the big question. Can I just thaw it out? Will it be okay? If the temp is now 35, I guess it will thaw eventually. However, should I let it sit out at room temp or even bathe the keg in warm water? It was a kick ass California Common at one point. I hope I did not ruin it. I also hope it did not ruin the keg it is sitting in, though it seems to have the same basic shape it started with. Dave Tucson, AZ Return to table of contents
Date: Tue, 16 Dec 2003 04:20:49 -0500 From: "-S" <-s at adelphia.net> Subject: re: RIMS Temperature Control Gary Smith responds to ... >> Temperature changes on the >> order of 1-2 degree F/min result in a ramp between >> steps taking almost as long as the targeted rests! >This is debatable. I agree but guys like Ludwig Narziss recognize this ramp rate as a serious problem over the protease range. The argument can't be ignored. >Too fast a temperature rise will >caramelize the sugars. Not generally true. The caramelization is due to localized high temps. As many have noted lower density (larger surface area) heaters and more flow solve this problem. Easier said than done. ==== Dave Towsend, correctly IMO, posits that mash accuracy below a couple degrees F is unnecessary. Then asks ... >So why is a >sudden jump in temperature needed for a multi-temperature mash? Because all modern malt is very well modified and most malts cannot stand much of a rest in the 50C-60C range(122F-140F) without losing foam and mouthfeel. If you mash-in low you must find a way to boost through this range relatively fast. If you examine G.Fix AoBT pp29 mash schedule you'll see his boost is essentially instantaneous from 40C to 60C - probably a boiling water bolus. Kunze suggests decocting with a mash-in at 62C/143F to avoid this problem. Like Ron LaBorde I feel HERMS is inherently more robust in this respect, tho' more difficult to automate.. == Most of the comments posted on enzymes are along the right lines. I disagree with some fine points in DionH's comments implying saccharification won't occur below gelatinization temps. Malt has considerable cold-water extract(CWE), releasing on the order of 25% of the available extract in cold water. So yes - some fractional part of the saccharification will occur at 122F. The other 3/4ths will await gelatinization as Dion writes. Malt gelatinization temps is in the mid-140sF, a bit higher than Dion suggests. Yes to prevent high attenuation levels you should bounce over this range and at least to the high 150sF rapidly. My *opinion* is that for HBers that a protease/peptidase rests with all malt grists must be limited to the absolute minimum necessary to prevent haze. That may mean a short rest in the high 130sF or a mash-in as high as 143F and thus a low saccharification rest w/ some protease activity. After a protease rest the *only* concern a brewer should have is to choose rests to favor or disfavor beta-amylase so to achieve the right level of attenuation. No commercial malt will ever leave starch after even a few minutes at mashout temperatures. It's extremely difficult to mistreat an all-malt mash so badly that it leaves starch. Mash-in temps even at 180F and a bit more will not leave starch. In short conversion is almost certain, focus on haze reduction and correct attenuation to style as the parameters to control by mash schedule. Brewing with large amounts of starch or raw grains will change this. -S Return to table of contents
Date: Tue, 16 Dec 2003 08:15:03 -0500 From: Steve Jones <stjones1 at chartertn.net> Subject: RE: RIMS temperature control Todd Snyder posts in HBD 4427: >> You use 1.5F/min. So to go from 122 to 154 took 48 >> minutes. Then you hold it at 154 for 60 minutes. Now why did they put that damn * key right next to the / key? It's too easy to hit the wrong one!! It's 1.5 degrees per minute, not 1.5 minutes per degree. Ramping up 32 degrees at 1.5 degrees per minute will take 21.33 minutes, not 48. Steve Jones, Johnson City, TN State of Franklin Homebrewers (http://hbd.org/franklin) [421.8 mi, 168.5 deg] AR Return to table of contents
Date: Tue, 16 Dec 2003 08:17:53 -0500 From: "Barrett, Bob (R.A.)" <rbarrett at ford.com> Subject: Re: Rogue Chocolate Stout There have been a few postings about Rogue's Chocolate Stout. In the latest Rogue eNews they mention how this beer is made: "Chocolate Stout uses Shakespeare Stout as the base, infused with the essence of Dutch bittersweet chocolate." Doug Hurst posted the ingredients that appear on the bottle, but did not include the yeast. Rogue uses their "Pac Man" yeast. It starts at 15 Plato and finishes at about 3.5 Plato. We make the beer we drink!! Bob Barrett Ann Arbor, MI (2.8, 103.6) Rennerian. Jeff was at the meeting on Friday but not Pat!!! Return to table of contents
Date: Tue, Dec 16 2003 9:18:11 GMT-0500 From: Jim Busch <jim at victorybeer.com> Subject: Karlsruhe When in this area of Germany, I always make a stop at the Hausbrauerei Vogel, either in Karlsruhe or its more suburban cousin Ettlingen. Here you will find one of the worlds most amazing unfiltered hefetrub Pils. Pick up a set of the nice schnapps glasses too. www.vogelbraeu.de When in Nurnberg, go directly north to Bamberg! Stop at any of the numerous small breweries throughout Franconia. Kloster Weissenohe is a favorite of mine. Prost! Jim Busch Return to table of contents
Date: Tue, 16 Dec 2003 09:29:48 -0500 From: "Todd M. Snyder" <tmsnyder at buffalo.edu> Subject: PID Control Mike Sharp writes: "The maximum ramping rate has nothing whatsoever to do with the type of control--it's the amount of power you apply to the heating chamber. " I agree completely. But if you have a low flowrate of wort and you set the heating chamber at the mash target temperature, it will take a long time to heat the _mash_ up to the target temperature. My point is that if you could heat the recirculating wort _above_ the target temperature to some safe but elevated temperature, you could get the heat into the mash faster and in something more closely resembling a step instead of a ramp. For example, lets say you want the mash to be raised to 154F and that you don't want the heating chamber outlet to exceed 160F. A PC based controller could add the heat as fast as possible without exceeding the 160 limit. When the heater has been 'on' the total number of seconds needed to add the required heat, the software stops adding heat even though the target temperature may not have shown up at any of the sensors. A PID is not smart enough to dump the heat in all at once. It 'sneaks up' on the solution with time when the temp sensor is installed on the outlet of the heating chamber. Then Mike missed the point about the scenario involving the probe somewhere in the mash, which _will_ cause a time delay in the control system. "If you're measuring the temperature at the exit of the heating chamber, the time delay is minor. " I agree completely, using a PID with the probe at the outlet at the heating chamber is a perfect application for a PID. Putting the probe in the mash or at the mash outlet is not. Putting the probe somewhere in the mash or at the mash outlet is a recipe for two problems. 1. Overheating the wort in the heating chamber because the controller is not 'seeing' what it's heating 2. Because of the time delay between applying the heat and seeing the temperature change: overshooting the temp in the mash and at the mash outlet. Todd Snyder Buffalo, NY Return to table of contents
Date: Wed, 24 Dec 2003 09:08:34 From: "C.D. Pritchard" <cdp at chattanooga.net> Subject: re: Transporting Kegged Beer Bob Hall asked for comments on favorite methods of moving kegged beer to parties, vacations, etc. I just strap them to a cheap moving dolly to move them but have thought about using a backpacking frame. To ensure clear brew, I always cold condition the secondary fermenter (a keg) then rack to a dispensing keg. This ensures any chill haze will form/settle and remain in the secondary. Keeping kegs cool is usually more of a problem than moving them.... For short term, I made a snug insulated sleeve that slips over a 5 gal. cornie. It's just 3 layers of blue foam sleeping bag pad material and an outer covering of aluminum faced bubble wrap. The first layer of pad is 1" taller than the other two- a couple of turns of rope secures it to the keg. Kept 5 gal. of ale drinkable for about 5 hours on a 90+ degF day. When used at room temp, I couldn't detect any temp. rise in the brew after 6 hours. For longer term dispensing from a cornie, I use a modified Rubbermaid 5 gal. round water cooler. With it's lid removed, a sleeve made like the above with 3 layers of sleeping bag pads was taped atop it and the entire thing (including bottom) was covered with aluminum faced bubble wrap. The wrap extends ~12" above the top sleeve. A Styrofoam lid with a slot for passage of the beer and co2 lines fits inside the outer wrap and atop the layers of pad and keg. The exceess bubble wrap at the top is gathered and tied to completely seal the affair. It also prevents the keg from floating upwards in the ice/water as it's drained. it uses very little ice- one filling (less than 7#) of ice lasted for 12 hours on a 90+ degF day followed by another 12 hours inside at ~70 degF- and there was still ice inside the thing. For smaller volumes, minikegs made from 3 and 5 liter PET bottles are the best IMHO. They are much easier to transport than a 5 gal. keg and will fit into a fridge at the destination. Details on them are via the URL below. I used to counterpressure fill them from a cornie but have discovered it's not needed. Purge 'em with co2, fill from cornie using a length of vinyl tubing attached to a cobra tap, put on tapping cap, connect to co2 and further purge a bit with the tap cap cracked open a bit then top-up the co2. For co2 while away from home, I use one of the tire inflator type co2 thingees. The cartridges are expensive but they are damn handy- especially relative to myonly other source- a 20# co2 cylinder. One useful addition is to splice in a pressure gauge and put a "red line" indication on it at the correct dispensing pressure- especially if others will be using the inflator. c.d. pritchard cdp at chattanooga.net http://chattanooga.net/~cdp/ Return to table of contents
Date: Tue, 16 Dec 2003 09:37:31 -0500 (EST) From: "Gregory D. Morris" <gmorris at literati.com> Subject: Yeast Cannibalism? I just kegged a batch of stout a while back, and I had been using one of those little bicycle pump-style C02 chargers to dispense it. It certainly wasn't an amazing beer, but it was certainly drinkable. The problem I have here is that it now smells and tastes awful. It has a burnt rubber-ish smell to it, that hbd has always attributed to yeast autolysis. However, I noticed that the CO2 cartridges I use kinda have that same smell, and I was wondering if that might be another cause for it. The keg was left half full, under pressure from the little CO2 cartridges for a few weeks, and it is my guess that the smelliness of the cartridges caused the beer smelliness. Has anyone else had a problem like this? - -- Gregory Morris Web Developer Literati (304) 296-8026 ext.139 gmorris at literati.com Return to table of contents
Date: Wed, 24 Dec 2003 09:44:27 From: "C.D. Pritchard" <cdp at chattanooga.net> Subject: re: How to throttle magnetic pump? Brendan asked "...if the best way to throttle the flow is to (1) restrict flow output or (2) use a dimmer switch to reduce power to motor. I understand that reducing motor speed would also slow the cooling fan, but I guess I could cool externally. Does outflow restriction have any negative impact on pump/motor? " Either is fine IMHO. For a RIMS or HERMS, it's been posted that pumps can damage enzymes but my experience doesn't support it. I switched from a discharge valve to a ceiling fan controller for the March MDX-3 RIMS pump a couple of years ago and didn't notice any change. Don't worry too much about motor heating- Although mine runs at much less than 1/2 speed for around an hour while mashing, there's been no motor overheating. Some tips if you go with a changing pump speed- at least for a March MDX-3: 1) A lamp dimmer won't work- use a ceiling fan speed controller. 2) Not all fan controllers work. I tried a couple before I found one which worked. The metal mounting plate is marked "Lutron FS-5F" - made by Leviton as I recall. 3) a variac (variable transformer) didn't work. Given the above, I'd been better off sticking with a valve to throttle the flow. If you go with a valve, a globe or even a gate type works better for throttling flow than a ball valve- often opening or closing a ball valve just a few degrees greatly/disproportionally changes the flow. c.d. pritchard cdp at chattanooga.net http://chattanooga.net/~cdp/ Return to table of contents
Date: Tue, 16 Dec 2003 06:43:52 -0800 From: "Parker Dutro" <pacman at edwardwadsworth.com> Subject: RE: Throttling Outflow of Magnetic Pump The safest way to control output is to use a ball valve or other adjustable valve on the exit port of the pump. For obvious reasons restricting flow to the entry port would cause the pump to cavitate. With magnetic pumps, it is alright to shut the output valve all the way off. I do this occasionally and the motor just spins and spins until I open the valve again. I don't do this for extended amounts of time; it would be advisable to switch the pump off instead to save from overheating and overworking it. "To every man, in his acquaintance with a new art, there comes a moment when that which before was meaningless first lifts, as it were, one corner of the curtain that hides its mystery, and reveals, in a burst of delight which later and fuller understanding can hardly ever equal, one glimpse of the indefinite possibilities within." C. S. Lewis Return to table of contents
Date: Tue, 16 Dec 2003 08:11:18 -0700 From: "Bob Speights" <rspeight at frii.com> Subject: Beer on a German Tour Stan, Do try Heidelberg if time allows. Vetters Alt-Heidelberg Brauhaus is worth a side trip. It's just off the church square in the center of town (Steing. 9). The fried sausages and potatoes are to die for (They make their own sausages and, of course, beer.) Take a prodigious thirst. They have a half dozen brews on tap at all times. And, do make ready to make friends - it's that kind of place. Enjoy, Dr.Bob Return to table of contents
Date: Tue, 16 Dec 2003 07:16:04 -0800 From: "Chad Stevens" <zuvaruvi at cox.net> Subject: RIMS thermal density In support of what Dion has already gotten across with what I thought was a reasonable degree of clarity...(heat shields up): For the love of Pete! The mash and the boil are two entirely different, detached, and diametrically opposed events in the beer making process. In the mash we want enzymes to remain intact; in the boil, we want to destroy the little buggers. In a RIMS setup we're not worried about caramelization or blowing up $7.00 heater elements or any other cataclysmic doomsday event you might envision. The central point is this: enzymes are not thermally stable. Get them too hot in your heater chamber and they can't do that voodoo that they do so well. Keep the watt density low! I feel better now. Can we go back to talking about beer? Anyone made Malt Vinegar? Pointers? Chad Stevens Return to table of contents
Date: Tue, 16 Dec 2003 09:30:28 -0600 From: "Ronald La Borde" <pivoron at cox.net> Subject: 5 gallons per minute >From: "Todd M. Snyder" <tmsnyder at buffalo.edu> > >But 5 gpm seems really really high to me. How can you get that much flow >thru the grainbed without compressing it? What flowrate do other RIMSers >use? Well, having not been there, I cannot say for sure just how that is done. However, I will tell you that I have never dreamed of achieving 5 gpm circulation rate. Oh, of course I tried to see just how much was possible on my system. Never got close. My conclusion is that the grain in the mash sort of semi-floats in the liquor, and when one circulates rapidly, the grain is pulled down and gets compacted more, more and more (3m). So, just how one gets 5 gpm flow rate is a mystery to me. I am not saying it cannot be done, but I don't know how. For a 5 gallon brew batch, I might get 1 gpm at the most. Normally when I do a 10 gallon batch, I will flow somewhere around .5 gpm. No matter how good the filter screen, It seems to me that the limiting factor is the grain's ability to float without compacting. Possibly with a super wide and shallow grain bed it would be possible. My system uses an Igloo 10 gallon cooler, and the bed will be about 15 inches deep. The photos I see on some rigs do have a much shallower mash thickness, perhaps this is the secret. On the subject of temperature probe placement, If the flow stops, does it really matter where the sensor probe is placed? This is why to my way of thinking, a stuck mash is the kiss of death to the brewing session using RIMS. The only way to keep the PID and heating element at desired temperature with a stuck mash would be if you had the temp sensor bonded to the heating element. That way the PID would be getting a steady diet of truth. For those who want to use computers, the ideal setup would be for several sensor probes throughout the system. In the mash tun, one probe at the top, one in the middle perhaps, and the computer then can figure out the average mash temp, which is what we really want. 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: Tue, 16 Dec 2003 09:35:10 -0800 From: "Mike Sharp" <rdcpro at hotmail.com> Subject: Re: PID Control Todd replies: > Mike Sharp writes: > "The maximum ramping rate has nothing whatsoever to do with the type of > control--it's the amount of power you apply to the heating chamber. " > > I agree completely. But if you have a low flowrate of wort and you set the > heating chamber at the mash target temperature, it will take a long time to > heat the _mash_ up to the target temperature. Well, if the flowrate is too low, the system is defective, and that's another issue. > My point is that if you could heat the recirculating wort _above_ the target > temperature to some safe but elevated temperature, you could get the heat > into the mash faster and in something more closely resembling a step instead > of a ramp. That's what PID will do, especially if you put the probe in the mash, the wort is hotter exiting the heater. You need to control the "amount hotter" by setting the max "on" cycle time. So when beginning the step, with your probe in the mash, you must configure your output so that when the controller is below the proportional band, the output is fixed to some maximum value (depends on the system thermodynamics). But this is risky, because you don't really know how hot the wort is getting at the exit of the heating chamber. It's possible to combine two controllers to do this so that you: 1. Control the max temp of the wort in the heating chamber 2. Directly control the mash temp. You have two separate controllers, one set for PID control with a probe in the mash, the other set for proportional control (PID is unnecessary here) with the probe at the outlet of the heating chamber. Ideally, you use an instrumented heating rod, as this has the fastest response time. This has the TC embedded in the end of the heating element (some have it in the middle, but these are used for other purposes). I have a heating chamber (which I actually use for other purposes) that is a straight cartridge heater with a K type TC embedded at the end of the rod. It's a fairly standard cartridge heater, and the heating chamber is a straight stainless tube with a swagelock T at both ends. The heater enters the "in" end, and sticks about 3/4 of the way up the tube. I'll post a picture this weekend. Anyway, the way this works is the two controllers control separate SSRs wired in series together with the heating element. When the system begins the step, the PID controller in the mash goes to 100%, because the mash temp is well below setpoint. The P controller in the heating chamber is also at it's max value, which depends on your system. Let's say you run your element at 100% power, because you have a low enough watt density. Very quickly the chamber heats up (but the mash hasn't). The P controller enters it's proportional band, which is set so that the max temp of the PB is the max "safe" temp for the wort. The heating chamber gets to the final temp quickly as the the P controller begins cutting back on output. Even though the mash PID controller is at 100%, the heating chamber controller is the one controlling power to the heater. Increasing flow at this point will cause the P controller to increase it's output, but temp will never go above the max safe temp. Let's say your controller stabilizes at 60% power. In practice, this actually decreases slowly as the incoming wort gets hotter. As the mash heats up (and it's doing it as fast as it can, given your systems characteristics), it eventually enters it's own PB, and the SSR (which has been wide open until now) begins to cut back. At some point, it's going to have a lower output than the SSR for the heating chamber. Remember, both SSRs are in series, controlling the same heater. The controller with the lower percent output is the one that actually controls. It's like having to valve in series. One can be wide open, but if the other is mostly shut, it's the one that controls the flow. Once the PID controller begins lowering output (as the mash heats up), the P controller will slowly increase it's output to your max setting (assume 100% for this example), because it sees heating chamber temperature falling, and it tries to raise it. But it doesn't matter, because now power is controlled by the mash temp. This approach allows 1. Exact mash temp control and 2. the fastest possible heating time. power-----| Mash SSR|-----|Heat Chamber SSR]----Heater > > For example, lets say you want the mash to be raised to 154F and that you > don't want the heating chamber outlet to exceed 160F. A PC based controller > could add the heat as fast as possible without exceeding the 160 limit. > When the heater has been 'on' the total number of seconds needed to add the > required heat, the software stops adding heat even though the target > temperature may not have shown up at any of the sensors. This is called "feed forward" control. Some systems--especially systems with long lag times from the time the controlled variable is changed to the time the wild variable is perceived to respond--can only be controlled by feed forward. The symptom is that with "feedback" control, the wild variable oscillates around the setpoint, and cannot be tuned in, or else it overshoots very badly, no matter what the tuning. Most modern process controllers that do PID allow feed forward control, but this is much harder to tune, and you must know the system thermodynamics intimately. It will change with different mash schedules. With systems that do not have fixed characteristics, it's difficult to come up with the tuniing parameter. You can obviously do the control with a PC, but what you're doing is essentially the same thing a dedicated process controller would do. You'd be better off using the PC as an MMI front end to the process controllers, and modify tuning parameters based on recipe selection which would be derived emirically, unless you remember more of your college thermo than I do... > > A PID is not smart enough to dump the heat in all at once. It 'sneaks up' > on the solution with time when the temp sensor is installed on the outlet of > the heating chamber. This isn't necessarily a characteristic of PID control, it's a characteristic of "feedback" control, which may be PID or not. A simple thermostatic control exhibits this same characteristic. > > Then Mike missed the point about the scenario involving the probe somewhere > in the mash, which _will_ cause a time delay in the control system. > Reasonable time delays can be tuned. Excessive time delays are symptoms of poor design. If the rare case occurs where the time delay is inevitable (especially if the delay is due to measurement delay, and not actual process delay), then you must use feed forward control. An example would be if you had a massive thermowell, and the mash heats up but it takes several minutes for your probe to measure it. Regards, Mike Sharp Return to table of contents
Date: Tue, 16 Dec 2003 14:59:36 -0500 From: Marc Sedam <marc_sedam at unc.edu> Subject: natural chocolate flavoring This topic comes up every now and again, from someone wanting to clone either Rogue or Young's Double Chocolate Stout. What you need to get is, really, called natural chocolate flavoring/extract. The one place I'm certain carries it is Williams Sonoma. At $10 for an 8oz bottle, it it a pricey little bugger. I don't know if you need a full bottle per batch or not, but that's what you need to get the chocolate flavor. I've successfully used cocoa in brewing but then you have to balance the bitterness of the cocoa with the bitterness of hops, etc. Can be hard to get right. Cheers! Marc - -- Marc Sedam Chapel Hill, NC Return to table of contents
Date: Tue, 16 Dec 2003 15:37:17 -0600 From: "Rob Dewhirst" <rob at hairydogbrewery.com> Subject: creating clear canned wort I have canned wort in a pressure canner in the past, for use with starters. The base was light DME. I stopped doing this because there was so much break material in the canned wort. I tried pre-boiling and then canning, but it did not help much. Any suggestions? Return to table of contents
Date: Tue, 16 Dec 2003 14:39:25 -0800 From: "David" <gates at island.net> Subject: Re: How to throttle magnetic pump? >I've got a new magnetic pump (from morebeer.com) and was wondering if the best way to throttle the flow is to (1) restrict >flow output or (2) use a dimmer switch to reduce power to motor. I understand that reducing motor speed would also slow >the cooling fan, but I guess I could cool externally. Does outflow restriction have any negative impact on pump/motor >Thanks in advance. Brendan, Throttle the output of the pump. The pump is a non-positive displacement pump so the normal practice is to throttle the output; this will not have any sort of adverse effect on the pump. Having said that, don't shut off the output and leave the pump running as you will burn out the seal on the pump and render it useless. David Gates Victoria, BC Return to table of contents
Date: Tue, 16 Dec 2003 18:35:40 -0500 From: David Towson <dtowson at comcast.net> Subject: Re: RIMS Temperature Control Wow, I've been away from the digest for a couple days, and there's been a lot of interesting stuff posted on this subject. Particular thanks to Steve for his good answer to my question about why rapid temperature steps are desirable, at least across the 122 - 140 F range. Todd asked some specific questions about my system performance, and I'll try to answer them now. I have a 3-tier system using 15-gallon stainless steel vessels. Each vessel has a natural gas burner under it, and I have individually ported the burners to get different heating rates. The HLT burner puts out the most, the kettle burner is next, and the mash tun burner is quite a bit lower than the other two. I only use the mash burner to pre-boil my water, and to provide a little boost heat during ramps, and then it's throttled way back so as not to overheat the wort under the false bottom. I had never measured the flow rate during recirculation, so I had to conduct an experiment to estimate that. I set everything up as usual, except that I used only water in the mash tun, and I put a bucket inside to collect the water so I could measure it. I have learned from experience how much I can open the throttling valve on the pump discharge before I risk sticking the mash, and that's where I set it for this experiment. I ran four trials, and averaged about 1.6 gallons per minute. For comparison, I ran one more trial with the throttling valve wide open and got 2 gallons per minute. In all cases, the water was being pumped through the HERMS coil, which offers a very substantial impediment to flow (45 feet of helf-inch copper tubing, plus five feet of half-inch hose and assorted plumbing hardware. In an actual mashing situation, I expect the rates will be a bit lower due to increased pump suction caused by the grist. Todd also asked about ramp rates. I only make one beer regularly that needs stepping, and that's an oatmeal milk stout. I do a glucan rest at 108, a beta rest at 138, an alpha rest at 157, and mashout at 170. I have clocked the ramp times on occasion, but never wrote them down. However, based on my memory of the most recent times, the ramp rate runs between about 1.0 and 1.5 degrees-per-minute depending on the temperature difference between the step temperature and the HLT temperature, with the greater difference giving the faster ramp as expected. While reading the various posts, it occurred to me that perhaps a different approach might be useful in addressing the question of whether a "fancy controller" can provide much faster steps in an electric RIMS. Let's assume for sake of discussion that all heat transfer is perfect, and there are no losses whatever. This example is for a step from 100 F to 150 F, a difference of 50 degrees, which roughly equates to a step from a glucan rest to a low single saccharification rest. From some web sources, I determined that water at 125 degrees (the midpoint temperature for this example) has a density of about 8.25 pounds-per-gallon. And since one Btu will raise one pound of water one degree F, it will take 8.25 x 50 = 412.5 Btus to raise one gallon 50 degrees. I do 10-gallon batches, which seems pretty common for RIM/HERM systems, and my usual amount of mash water is eight gallons. That's how much it takes to cover my temperature probe, which is installed in place of a dial thermometer that came with my equipment (a Sabco keg). So there's no fancy reason why I put it there; it's just where I could put it. I did, however, intentionally keep the probe short, so it "sees" the temperature near the outside of the keg, where the heat loss is greatest. Going on with the example, to raise 8 gallons 50 degrees, will take 412.5 x 8 = 3300 Btus. Now, here's where we get to the meat of this example. To develop one Btu in one hour takes 0.293 watts. So using the example target of 3300 Btus and this relationship, we can generate the following table showing the power needed to get our 50-degree temperature change in various fractions of an hour. 5 minutes 11,603 watts 10 minutes 5,801 watts 15 minutes 3,868 watts 20 minutes 2,901 watts 30 minutes 1,934 watts These are the powers needed to raise 8 gallons of water through the example 50-degree step in the times indicated. And this is for a perfect system with no losses, with the heater turned on full, and left on until the job is done. In other words, there is no controller - just a switch, and heating occurs at the maximum possible rate. But a real electric RIMS is not a perfect system, and it has losses. So more watts than those shown above will actually be needed to do the 50-degree step in the times shown. The reader can scale the above powers upward by whatever factor seems appropriate to account for system losses, but whatever the factor, were talking some serious power levels here for rapid steps. And unless those watts can be converted into heat in the wort in the specified time without damaging the wort through excessive local heating, the indicated step times cannot be achieved no matter what kind of controller is used. I have no experience with an electric RIMS, but I suspect that doing really fast steps with such a system will require a truly huge multi-element heating chamber and a high flow rate, in order to have the power needed while keeping the wort temperature within a safe range. If I were building such a system, I'd want to have solved that problem before I spent a lot of time thinking about a fancy controller. Dave in Bel Air, MD Return to table of contents
Date: 16 Dec 2003 18:41:56 -0800 From: Dion Hollenbeck <hollen at woodsprite.com> Subject: Re: RIMS Ramp Rates, PID Controlled etc >> FRASERJ writes: JMF> I am guessing a PID Controller would throttle my system using JMF> power control (cutting back on wattage) better than my hard JMF> ON/OFF control of the elements would. Actually, the PID controller does the same thing, ON/OFF only. It does not directly cut back on wattage. There are some PID controllers capable of outputting a voltage level corresponding to a percentage of full on, but I don't see how that could control a heater element without some more sophisticated electronics sitting between the element and the PID capable of sensing the PID voltage level and translating it into some sort of sine wave clipping like a dimmer switch does. Most likely possible to do, but most RIMS systems I know of use PID controllers that do ON/OFF, varying the percentage of ON/OFF as the setpoint is neared or lost. This percentage and the number of seconds one ON or OFF unit is can generally be set in the PID. dion - -- Dion Hollenbeck Email: hollen at woodsprite.com Home Page: http://www.woodsprite.com Brewing Page: http://hbd.org/hollen Return to table of contents
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