Digital Thermometer in the Mash Tun

Question for you all... Those of you that have the rubbermaid coolers anyone use a digital thermometer to regulate your mash temp? How do you do it? Drill a hole in the lid? I'm afraid of heat loss if I do that.. But it is so cool to see the mash temp...

Lots of people do use them, there have been a couple of threads I know of. The cord is made to be closed in an oven door, a cooler door is not too much different. The cor will wear out, but what is 15 bucks once a year or so?
They are great, but you need to coat the cord or it will deteriorate.

I just stick my probe in the mash and close the lid, no problems so far.

TheJadedDog said:

I just stick my probe in the mash and close the lid, no problems so far.

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I do this as well. The only problem I've has has been the probe getting too far into the mash and it stops working. I don't think it is water proof at the point where the wire comes out of the probe.

heat shrink the entire submerged part of the cord

ohiodad said:

Question for you all... Those of you that have the rubbermaid coolers anyone use a digital thermometer to regulate your mash temp? How do you do it? Drill a hole in the lid? I'm afraid of heat loss if I do that.. But it is so cool to see the mash temp...

Click to expand...

I drilled a hole in both my 5 and 10 gallon coolers. No heat loss.

If the mash level is too low too low for the metal probe to reach...just dangle it in over the rim and then tighten down the lid.

Don't submerge the plastic or the braid in the liquid:

RichBrewer said:

I do this as well. The only problem I've has has been the probe getting too far into the mash and it stops working. I don't think it is water proof at the point where the wire comes out of the probe.

Click to expand...

Yeah I use the lid to hold the probe in place. I submerge it right up to where the cord is attached.

I've never lost more than a couple degrees over a couple hours in one of those Rubbermaid coolers. Once I hit my target temperature, I just put on the lid and forget about the mash until it's time to do something with it.

For temperature readings, I use the dial thermometer with the 12" stainless probe. It gives me a reading in a few seconds, is rigid enough to let me stir it around the mash to see if there are hot or cold pockets, cost me about $5 when I bought it many years ago (and is only about $10-15 now), and is rugged enough to leave in the mash tun with the lid on.


TL

I have gone through a bunch of those thermometers because of the cord getting wet. I just saw that those truetemp thermometers now have a coated cord. I think I might go get another one soon.

I've got a rectangular cooler, so I've always just set the probe in the mash and closed the lid. But as TexLaw says, you don't really lose a lot of heat, so it's not really all that critical, it seems, to keep check of the temp.

Yesterday, in fact, I didn't use my probe thermometer, it's messed up and I haven't been able to futz with it to get it working. But, I have a digital pen thermometer that I like a lot and that seems to work great. I used that to confirm I hit my temps, then closed the lid and walk away for an hour.

When I opened it up, I found not that I had necessarily lost any total heat, but that there were a lot of hot and cool spots. One corner was still at the 155° I had originally set, while other spots were right about 150°. Now, I stirred well before closing the lid, but I'm not sure whether I needed to stir MORE or whether I lost heat from the cooler unevenly. I also never stirred the mash once I had the temperature set, figuring it was better to have uneven temp than to lose some heat when I opened it back up.

Lesson being - there can be a material difference in mash temp depending on where you are taking your measurement (and my hottest spot happened to be near a corner, not what I would have expected).

This is mine. I got the thermometer + probe at Wal-Mart for 15.00, and it is a sealed-type, meaning that it can be completely submerged in wort and still read correctly (The probe, not the "base unit".)

I use the paint can to help keep the lid shut, because the probe cord is meant to be closed into things with a little bit of pressure.

I wouldn't recommend a TON of weight, as that could damage the cord. I find that an old, half-full paint can is just enough weight to help retain temps, but still protect the cord.

If you want, I can take a close-up snapshot of the probe + cord tonight so you can compare with others.

I use 2 of those thermos. I think they work great. I never had a problem with them fully submerged, even while stirring the probe around with the grain. I've got them in my thermosights on my kegs now.


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Lil' Sparky said:

...even while stirring the probe around with the grain...

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Heh heh... guilty as charged, I stir mine with it too. I know I shouldn't, at least if I want to keep using it for a while... But lazy men can't be changed

I didn't bother drilling a hole in my lid, I just flip it over. Then just run the cord through the ridges on the lid. It holds heat just as well.

The picture doesn't really show it, but you can easily waterproof the cords on the temperature probes by slipping some silicone tubing over them. Mine fits REALLY tight and is absolutely waterproof (and heatproof, if I still want to use it in the oven).