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Thermometer for my mash tun, old jv northwest mash tun

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  • Thermometer for my mash tun, old jv northwest mash tun

    I have a JV Northwest 10 barrel mash tun that currently has an analog Thermometer on the side of the tun by the Door. When mashing in currently I have to constantly run down and check the temp, it is a pain in the ass. I would like to install a digital probe in the thermowell and attach it to a digital thermometer that I can set up on my platform so I can actually see the temp as I mash in.
    Does anyone else have this type of set up and have any recommendations? I was looking at the RTD sensor from gw kent but was not sure what thermometer to get for this probe and if this was the best way to go?

    Thanks,
    Derek

  • #2
    RTD Selection

    The GW Kent RTD is a good choice for a sensor, but I couldn't find a readout on their website (aside from the Ranco/Johnson controller that the sensor is normally paired with).

    A few things to keep in mind with RTDs:
    1. Make sure the probe fits in the thermowell (length, thickness and threaded connection).
    2. Stay away from 2-wire RTDs if you can - they are sensitive to interference, even with shielding. 3 or 4-wire is better (and sufficient for mash temp). An RTD with attached transmitter is best (but usually more expensive).
    3. Make sure your readout device power requirements match your brewery. If you don't have a control panel, you probably don't have 24V available, so the readout should be powered by 110V.
    4. If you shop for other models outside the GWKent, don't go too cheap - you get what you pay for with instrumentation.

    I would call GWKent and see if they can get you a readout for that RTD. If not, I can help you track down an inexpensive substitute.
    Kyle Kohlmorgen
    Process/Automation Consultant
    St. Louis, MO

    Comment


    • #3
      Why not by a good long stem digital probe handheld? I find most of the temp probes in smaller mashtuns are woefully inaccurate especially if you dont have a good mixer. They generally stick a few inches into the tun in one spot near the bottom and are only accurate for that one spot. A good probe will show you if you are getting hot or cold spots or hopefully a pretty even temp across the bed. If I paid attention to the probe on my mashtun Id be a few degrees off every time.

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      • #4
        I am assuming you are mashing in by mixing hot water and grist and running the mix into the mash tun.

        Measuring the mash temperature at a single fixed point adjacent to the MT wall throughout the mash will not give you a meaningful reading as the mash does not flow past that thermometer. The result will be virtually meaningless as it is not representative of the whole mash, but just the couple of static inches of mash around the probe.

        If you measure the mashing liquor temperature and keep that consistent, then you will get a consistent mash temperature. If, after mashing, you measure the mash temperature with a hand thermometer, then you can adjust for the malt temperature, which may vary with the season. Better still, measure the mixed mash immediately after mashing and adjust the hot and cold liquor (normally just the cold) flow rates as it mixes with the grist. Again, measure the final static mash temperature at a number of points, and if you need to, you can adjust the mashing in temperature a little to achieve the "in tun" mash temperature.
        dick

        Comment


        • #5
          Temp sensing

          Originally posted by SouthHouseBrew View Post
          The GW Kent RTD is a good choice for a sensor, but I couldn't find a readout on their website (aside from the Ranco/Johnson controller that the sensor is normally paired with).

          A few things to keep in mind with RTDs:
          1. Make sure the probe fits in the thermowell (length, thickness and threaded connection).
          2. Stay away from 2-wire RTDs if you can - they are sensitive to interference, even with shielding. 3 or 4-wire is better (and sufficient for mash temp). An RTD with attached transmitter is best (but usually more expensive).
          3. Make sure your readout device power requirements match your brewery. If you don't have a control panel, you probably don't have 24V available, so the readout should be powered by 110V.
          4. If you shop for other models outside the GWKent, don't go too cheap - you get what you pay for with instrumentation.

          I would call GWKent and see if they can get you a readout for that RTD. If not, I can help you track down an inexpensive substitute.
          The easiest is a Type "J" thermocouple with a digital gauge. Automation Direct has very inexpensive products that work very well.
          Also, use thermo well grease (food grade) in the well to transfer the temp to the thermocouple. When you mount the Thermocouple, make sure there are no leaks in the well itself on the inside of the tank. I have seen pin holes where the grease would get pressed though it into the tank when the Thermocouple is inserted.

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