How Do You Measure Grain Temperature?

Discussion in 'General Brewing Discussions' started by Thurston Brewer, Oct 10, 2016.

  1. Thurston Brewer

    Thurston Brewer Active Member

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    The BF Strike Water Calculator wants to know the temperature of the grain. I set the bag of grain on the counter next to a glass of water overnight, then before mashing I measured the water temp and used that as the grain temp; since they had both had time to reach the normal ambient temperature it's logical that they would have the same temp, right?

    I'm asking because the strike temperature I got from the BF Strike Water Calculator was so badly off... I'd like to find out why and grain temp is the only thing that I'm not super sure of...
     
  2. MarylandBrewer

    MarylandBrewer New Member

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    i just place an instant read thermo into the bag of grain and get temp that way. i know it is not an exact measure of the grain, but of the air in the spaces between the grains. But like your water measurement, it should be darn close.

    But i sincerely doubt that the grain temp is the culprit in the calculation if it registered as nearly same as the air temp. more than likely a misreading on thermometer, or missing thermal mass, or ?
     
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  3. jeffpn

    jeffpn Well-Known Member

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    I just looked at the closest thermometer when I wanted to know my grain temperature. Now I just add 6-7° to my mash temperature and call that my strike temperature. It's always close enough to me. The important thing is to allow the water temperature to stabilize before checking it. My method is to turn my heat source (propane) off, and wait about 3-4 minutes to let the water temp max out. Then I check my floating thermometer to make sure it's where I want it to be.
     
  4. Thurston Brewer

    Thurston Brewer Active Member

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    Let's see. The variables were:

    Grain weight: 6.25 lbs
    Grain temp: 68 °F
    Mash thickness: 1.25 qt/lb
    Mast temp: 153 °F

    Strike Calc says I need:
    1.95 gals @ 166.1 °F

    My resultant mash temp was 146 °F. Next time I'll try adding 5 °F to whatever the calculator says.
     
  5. Trialben

    Trialben Well-Known Member

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    I don't measure grain temp any more and I don't use Brewers friend strike calculated for mash in. I heat strike water 2c above intended mash in temp and usually It drops 2c regardless of grain temp maybe a bit rough and shoddy on my part but it works for me :)
     
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  6. Head First

    Head First Well-Known Member

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    #6 Head First, Oct 10, 2016
    Last edited: Oct 10, 2016
    The software takes into consideration what it can. If you check the about portion(little question mark) it explains that there are other factors that you will have to consider for your own setup. mash tun temp is only one of them. Everybody will have some variation. I strike with 15-20F higher than what I want to mash at without insulated tune and grain is kept in a cool storage room. 8degrees off really isn't bad for first shot at it. Doing a 5 degree change should get you in the ball park.
     
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  7. Trialben

    Trialben Well-Known Member

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    And you can always add boiling water or do a mini decoction to bring up that temp if too low. Or go the other way if too hot add cold water.
     
  8. Thurston Brewer

    Thurston Brewer Active Member

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    My strategy is a single infusion in an insulated mash tun, and I want to be able to control the thickness of the mash, so I really want to be able to determine in advance what water temp I need at a given volume and weight of grain to achieve my target mash temp.

    All in all, I guess I need to just look at my first experience with the calculator as a baseline, and adjust from there. It seems that my personal setup requires about 6 degrees higher strike temp than the calculator calls for, so if that adjustment holds true I can just compensate for the difference between the assumptions made by the calculator and my particular setup.
     
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  9. Trialben

    Trialben Well-Known Member

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    Yep true that thirsty same mash water volume same grain volume same pre strike temp +6 degrees you should hit your mash temp practice makes perfect aye. I don't really take this strike temp too dramatically as I'm sure there are bigger variables to contend with in brewing. Even mash thickness mines like 6lt per kilo not sure if that makes sense to ya but I pretty much mash a full volume and just sparge with a few liters to hit pre boil volume. I've also herd a full mash can lead to more malty flavour. I know I rave on about it but check out www.brulosopher.com he tests all the brewing conundrums out you can glean some valuable in sites into brewing misnomers from his exbeerments. Cheers:)
     
  10. Head First

    Head First Well-Known Member

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    Yup you have the right idea. You could warm up your mash tun before you start your mash, but being consistent is the key you are needing to hit your numbers closely all the time. In a 5gal batch a qt of boiling water won't change your ratio that much but can give you a few degrees to help while you zero in. Setting your stuff out to start at the same room temp every time is a good baseline to follow up other batches with. You are on the right track:)
     
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  11. sbaclimber

    sbaclimber Well-Known Member

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    #11 sbaclimber, Nov 2, 2016
    Last edited: Nov 2, 2016
    ^^ what HF said.
    I tried the calc originally too and found the numbers were way off for my particular setup. After many brews, I can predict pretty accurately what the temps will be and can adjust the calc accordingly. (e.g. 22l strike-H2O @ 72°C + 6 kg Malt @ 20°C = 67°C Mash temp)
    Why the default settings are so far off for my setup, I cannot say, but running 2-3 brews of similar dimensions should give you an idea of how your setup will behave and you can then adjust accordingly.

    PS, I just punched the numbers above into the calculator, and they came out +- 1°C about right. :)
     
  12. Ozarks Mountain Brew

    Staff Member

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    your grain temp is probably your outside air temp, close enough but I use 160 as my water temp and that offsets to 152
     
  13. Thurston Brewer

    Thurston Brewer Active Member

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    I think I'll stick to the strategy of measuring a cup of water that has been in the same environment as the grain for at least 12 hours. That way both will have reached the same ambient temperature, and my thermometer is designed for measuring liquid temperature so it would only really be accurate at measuring the water, not the air or the grain itself.

    And even though I do preheat my mash tun, it seems like +6 °F added to the calculator comes out just about right.
     
  14. jeffpn

    jeffpn Well-Known Member

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    Leave the thermometer next to the cup of water over night. I'd be interested to know what the thermometer reads before submersion.
     
  15. Nosybear

    Nosybear Well-Known Member

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    I poke my thermometer into the grain bag and let it stabilize. Works fine! Where I get my variability is in the temperature of the mash tun.
     
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