Thermometers

Richard · February 22, 2011, 05:30:56 PM

Ok, so I have one of those digital thermometers with a probe on the end of a long wire. Just the other day it decided that boiling water was 103C so I gave it a little test against the other thermometers I had lying around. The other two I had (electric) both agreed that the temperature of boiling water was (shock; horror) 100C. So I've been using a thermometer for my mashing which is basically, broken.

Just wondering if people have any particular model or brand they swear by. I'm fairly sure a stuck ferment I had off my second AG batch is down to bad mash temperature control.

Kyle · February 22, 2011, 08:37:52 PM

If the long metal probe of the digital thermometer was near the bottom of the pot, it might be slightly above 100C, since the burner is right under it

Richard · February 22, 2011, 08:52:52 PM

this was fairly consistent regardless of position... although I now think I might have broken the probe by immersing it :roll:

Hawoh · February 22, 2011, 10:37:41 PM

There is a waterproof digital probe thermometer at Davidson Food Equipment, but without knowing, I'm guessing it would be rather pricey.

Another option is to waterproof your next one. I lost the link where I had found the idea (I had the same mishap).
- Get silicone aquarium air tubing (by the foot) at one of the local pet stores
- Run the probe through, stopping just before the wiring
- Seal with 1-2 rubber o-rings (Hardware store, don't know the size off the top of my head)

If I remember I'll take a picture of mine and post it... it seems to work great.

Also, after ruining my first one, I experimented with a couple thermometer iterations. So now I have 2-3 in my mash and strike water. Between them all, I'm covered if one is mis-calibrated or fails.

Hawoh · February 23, 2011, 09:17:00 AM

The pictures

Richard · February 23, 2011, 12:01:47 PM

Thanks for the photos -- makes sense now I see it. not sure about the o-rings but I suspect it'll be clearer if I just wander into an aquarium store with the probe and have a little look at the tubing

btw -- yours says "over by 3C" -- I read something that suggests you need to interpolate between 0C and 100C for actual offsets, as it varies with extremity. I also read that you can fix these damn things by basically cooking the probe at a high temperature, which I'm going to try today. $20 is $20, after all.

Hawoh · February 23, 2011, 01:09:22 PM

I think the rubber O-Rings are 3/8" - Can find them in the plumbing section of the hardware store

The +3°C note on that is a note to myself in relation to the several thermometers I have. Calibrated them all together, and this one is off by +3 relative to the one I deemed to be the most accurate.

Richard · February 23, 2011, 01:36:26 PM

Is it really a constant +3C across the 0-100C range? Must be broken firm/software if so.

Shawn · February 23, 2011, 01:42:07 PM

A little late to be getting into it... but I used to have one of those same type of thermometers - probe on the end of a long wire. Now I just have one that has a ~2.5-3 inch probe sticking right out of the thermometer, which itself isn't much bigger or thicker than a pen. Seems to work great (when I tested it at freezing and boiling, it was pretty much spot on), and only cost 8-10 bucks at Canadian Tire.

If you want, I'll take a look at the brand when I get home and let you know.

Richard · February 23, 2011, 01:45:02 PM

Shawn: one of the other ones I tested this against was probably exactly the same one you're talking about. I prefer the ones with a probe on a wire, though, because I can just dunk it in whatever I'm measuring and seal things up over the top of it.

Hawoh · February 23, 2011, 02:02:47 PM

Quote from: "Shawn"A little late to be getting into it... but I used to have one of those same type of thermometers - probe on the end of a long wire. Now I just have one that has a ~2.5-3 inch probe sticking right out of the thermometer, which itself isn't much bigger or thicker than a pen. Seems to work great (when I tested it at freezing and boiling, it was pretty much spot on), and only cost 8-10 bucks at Canadian Tire.

If you want, I'll take a look at the brand when I get home and let you know.

I think I may have the same one Shawn is talking about, if so, I believe Taylor is the brand on mine. I've found that one to be the most accurate of my collection.

Richard · February 23, 2011, 02:06:22 PM

Aye that's the one I've got without a wire... Taylor 9841. I guess I'll just use that for exact measurements.