Inconsistent Temp Loss in Mash Tun :( Remedies??

Discussion in 'Homebrewing' started by larstheberserk, Mar 12, 2012.

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  1. larstheberserk

    larstheberserk Initiate (0) Sep 4, 2010 California

    Hey guys, currently I use a topless keg as my kettle and have a nice 10 gallon insulating Mash tun for single infusion mashing. Yesterday I had a a killler IPA planned, but it kinda got mucked up because of the temp loss from the kettle to the mash tun. Normally, depending on the weather, I heat the mash water up to 15-20 degrees higher that my projected mash temp to make up for the heat loss in the water transfer and the grain, and usually my estimates result close-ish to my intended temps. Yesterday, it was in the low 70s with a light breeze, so I figured 15 degrees over my strike temp of 152 (so 167) would suffice... wrong! The mash temp ended up being 140 degrees!!! 27 degrees of heat loss! I threw some extra boiling water in it to bring it up to 145 and extended the mash time to try and make up for it, but I can tell by the O.G. that it royally screwed up my batch :slight_frown:
    Does anyone have some good rules of thumb to end up with slightly more accurate mash temps with my setup? I'm thinking that I should just start doing 30 degrees over and have some frozen water bottles on hand to cool it down if I have to. Too high of temps are waaay more easily fixed than too low of temps eh?
     
    #1 larstheberserk, Mar 12, 2012
  2. GreenKrusty101

    GreenKrusty101 Initiate (0) Dec 4, 2008 Nevada

    Good thing you had an IPA planned...the low mash temp probably didn't hurt too much. I use a cooler also and I can tell you to preheat with hotter than strike temp water and let it sit for 10 minutes. Insulating your ball valve with a wash rag and throwing a towel on the lid should help, too.
     
    #2 GreenKrusty101, Mar 12, 2012
  3. VikeMan

    VikeMan Grand Pooh-Bah (3,067) Jul 12, 2009 Pennsylvania
    Pooh-Bah

    I would treat this as a 'mash tun absorption heat loss' problem rather than a 'transfer heat loss' problem and dial it in from that standpoint.
     
    #3 VikeMan, Mar 12, 2012
  4. jthahn

    jthahn Initiate (0) Jun 1, 2009 Indiana

    you've got some more considerations to take into account.

    1) What is the temp of the grains? Obviously the colder they are the warmer the strike water will need to be.
    2) Volume. 7lbs. of grains wont absorb as much heat as 15 lbs. of grains.

    you said you were making an IPA, is it your first IPA with this setup? I wonder if its the most grains you've used with your current setup? The more grains you have the warmer your strike water will need to be. Basically, you've got to get familiar with your equipment and recipes.
    A warm day doesn't necessarily mean warm grains. Was your mash tun still cool from the colder temps you may have had recently? more heat loss.

    You've got a good idea with starting 15-20 degrees higher, but as you just found out it may not always do it.
    Here are some things I like to do.

    -Keep grains inside the house during the winter months (or so long as its under 70 outside)
    -Bring the mash tun in the house the night before. Again just to help keep it warm in the cooler months.
    -Have extra hot water AND cold water on hand when striking in.
     
    #4 jthahn, Mar 12, 2012
  5. larstheberserk

    larstheberserk Initiate (0) Sep 4, 2010 California

    Thanks for the advice everybody!
     
    #5 larstheberserk, Mar 12, 2012
  6. pneumaticaxe

    pneumaticaxe Initiate (0) Mar 3, 2010 New Jersey

    There's a bunch of infusion calculators out there that will def help you out. It's not that great of an idea to just "guess" the strike water temp. I personally use this one http://www.brewersfriend.com/mash/ and its been pretty spot on. That takes in to account the temp of your grains which I think was your first problem. The other thing is warming up your mash tun before you strike. I'm gonna guess you lost all\most of your heat this way. I usually add about 2 or 3 gallons of hot water to my 10 gallon mlt and let it sit for 10ish minutes with the lid on before I start mashin'. I just take the hottest water possible from my faucet which is around 165 degrees but I think anything 120 or more would work fine. As long as you get that thing toasty.
     
    #6 pneumaticaxe, Mar 12, 2012
  7. joshodonn

    joshodonn Initiate (0) Jan 21, 2011 Florida

    I use BeerSmith to calculate my strike temps and it is spot on almost every time....
     
    #7 joshodonn, Mar 13, 2012
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  8. wspscott

    wspscott Pooh-Bah (1,958) May 25, 2006 Kentucky
    Pooh-Bah

    #8 wspscott, Mar 13, 2012
  9. WickedSluggy

    WickedSluggy Savant (1,129) Nov 21, 2008 Texas

    Consider a means of heat/recirculation like RIMS or HERMS. You can DIY a RIMS tube for about $25. You'll also need a pump and a PID controller. It is awesome to sit back and watch that thing maintain your mash temp with no troubles at all.
     
    #9 WickedSluggy, Mar 13, 2012
  10. larstheberserk

    larstheberserk Initiate (0) Sep 4, 2010 California

    Niiice, I like that calculator wspscott... funny thing though... the strike water temp it calculated is exactly what I estimated (167.0 degrees) so I guess the main thing is figuring out how I lost that other 12 degrees (apparently not from the grain temp)... I'm guessing it's a combo of the mash tun temp and the transfer from the kettle to the mash tun... maybe my new rule should just be add 12 degrees to the temp this calculator figures out eh eh??
     
    #10 larstheberserk, Mar 14, 2012
  11. Pegli

    Pegli Initiate (0) Aug 30, 2006 Rhode Island

    Something's fishy - that's a LOT of heat loss. I brew outside in below freezing temps and never have to heat my strike water more than 20 degrees above mash temp...
     
    #11 Pegli, Mar 15, 2012
  12. larstheberserk

    larstheberserk Initiate (0) Sep 4, 2010 California

    I know right? What the heck? What about getting a release valve at the bottle of the kettle?? (instead of having to pour) or is there just some other mysterious cooling force that I'm missing? I live in SoCal so there's really not that much going on in the way of "cold" lol
     
    #12 larstheberserk, Mar 15, 2012
  13. Pegli

    Pegli Initiate (0) Aug 30, 2006 Rhode Island

    Pre-warming the mashtun (1/2 gallon of 150ish water a few minutes prior to mashing) helps alot...
    Great avatar BTW
     
    #13 Pegli, Mar 15, 2012
  14. larstheberserk

    larstheberserk Initiate (0) Sep 4, 2010 California

    been hearing that pre-warming the mash tun helps a lot... will try it out this weekend and report the difference. glad you dig the avatar! :grinning:
     
    #14 larstheberserk, Mar 15, 2012
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