Wide Variation in Wort Temp Readings

Discussion in 'Beginners Brewing Forum' started by hundel, Jul 19, 2018.

  1. hundel

    hundel Member

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    When I use a brew-in-bag approach for small batches (5 gallons) in a 6.5 gallon kettle, my digital thermometer readings vary by 10 degrees depending on where I place the thermometer in the wort.

    My process is typical. I place the bag in the kettle, bring the water to several degrees over my target mash temp, pour the grain in gradually and gently stir a few times - just enough to break up dense clusters at the bottom. I do not pick up the spoon again and I do not mix thoroughly on advice from others.

    I have no trouble with the mash temps dropping over time when taken on average at many points in the kettle. A typical mash for me might have areas that read 157 and others that read 148.

    The mash can get a bit dense with my heavier grain bills (14.5 lbs) but not more than runny oatmeal.

    Since the mash temp plays one of the biggest roles in the results it’d be nice to not have to average such widely varying numbers.

    Some would definitely freak out most people if the wort were all that warm. In general my results are good but could be critiqued as having too much for a style on occasion - possibly due to some parts of the wort building out extra long strand sugars that the yeast can’t ferment. It’s subtle and I don’t know this to be the cause but I’d like to know for sure what temp my wort is mashing at.

    Am I being too cautious about stirring or is a small crowded kettle inevitably less even in temp than a larger insulated mash tun?
     
  2. Nosybear

    Nosybear Well-Known Member

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    Variation is inevitable. Just stir more. I think the "don't stir" faction is afraid of oxygen. Stir gently, don't whip air into the mash, and relax. At our scale, variation is a way of life.
     
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  3. Michael_biab

    Michael_biab Member

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    Agree with recommendation above. In my BIAB experience, give it a better, more even stirring and don't worry too much about adding oxygen. I've not had negative issues arise from this.
     
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  4. Nosybear

    Nosybear Well-Known Member

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    I don't BIAB but I do stir my mash well before taking temperature. Make sure everything is mixed and there are no dough balls, let it set for around 5 minutes, then take your temperature. Since you're already aware of the variation that can arise, you'll understand when I say close is good enough.
     
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  5. Trialben

    Trialben Well-Known Member

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    Yep as above give it a good stir i would. I am stiring constantly one hand whilst i take temp reading with probe at mash in and at 15 min or so intervals and for mash steps.

    Only way i think you can get a more even mash temperature profile would be recirculate mash that way.its constantly agitated or moving and less hot spots should occur.
     
  6. Blackmuse

    Blackmuse Well-Known Member

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    When I did BIAB I stirred I real well and then let it ride. When I first started I got the same thing you did Hundel and then worried as well.... Eventually I figured I'd my highest temp was close enough to my mash in then the rest would still convert. Maybe that wasn't the way to do it but my logic was if I wanted 154 and the center if my mash was 156 and the outskirts were 146-150 then all in all, conversion was happening! Made some great beer with BIAB - technically still am I suppose wince most consider the robobrew similar to BIAB.
     
  7. Ozarks Mountain Brew

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    thats why its hard to get a boil gravity reading for most people, its just not a reliable reading
     
  8. Hawkbox

    Hawkbox Well-Known Member

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    I generally pull 2 readings for each stage and as long as they're close together I call it a win.
     
  9. philjohnwilliams

    philjohnwilliams Well-Known Member

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    I stir like hell for the first few minutes of the mash, and after about 4 minutes my temps are pretty consistent, no more than 2°f variation in readings from different locations in the mash. It is important when stirring that you not only stir in a circle, but also stir to move the mash from the bottom to the top. I find alternating between a few strokes horizontally and a few vertically helps me get a stable temperature quickly.
     
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  10. Ozarks Mountain Brew

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    I have a thick mash usually 20 pounds if grain so i do the shovel stir push from the bottom then top to bottom, stiring in a circle doesn't work for me too much work
     
  11. hundel

    hundel Member

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    Okay. This time I stirred with a typical spiral and counter spiral motion for 20-30 seconds and this is a thinner mash so temps seemed to settle within 3-4 degrees. I know my strike water temps and how it affects my beer from a large number of roughly similar batches so this is more for conformation. The really useful thing for me in your answers is that the people answering the ‘how much are you stirring question” I didn’t ask, but was obviously the key factor made me realize I was taking a “don’t stir too much” recommendation from years ago way to seriously and its possible my thicker mashes had a heavier body and less fermentable sugar profile due to hot pockets that stuck around longer and likely have a much bigger impact on beer than a minute of stirring.
     
  12. Ozarks Mountain Brew

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    the only real way to keep a constant temp is to recirculate with a pump, you don't even have to recirculate constantly but it will even out the temp and you can turn the heat on while you do it
     
  13. hundel

    hundel Member

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    Makes sense. I can see upgrading my mash setup in the next few years. It’s a weak point but serving me adequately.
     
  14. hundel

    hundel Member

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    I actually learned something else really interesting and funny. My readings on settled mash without stirring are much cooler on the left. But the right is consistent now. Cause for concern? Not if you’re mashing in the kettle. A significant amount of condensation can run off the lid and into the part of tour mash that’s under your lid-holding hand. Ha.
     
  15. Ozarks Mountain Brew

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    you could do whats called condition the grain before mashing and really all that does is soften the grain outer shell with cold water in a bucket then when you mash, temp variations are less likely, it's really not the water as much as the grain becoming soluble at different time periods
     
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