I’ve used a gnarly old candy/oil thermometer for years to judge the temperature of oil for deep-frying, and it’s a pain. It gets greasy and it’s hard to clean. Mr. brown suggested one of those gun-like infrared laser thermometers, but I’m doubtful if they’ll work if aimed at oil. It seems to me that they’re for judging the temp on a hard surface, like a skillet.
Does anyone have one, and have any insight if they work on deep, clear oil?
I think it’s only going to tell you the temperature of the surface of the oil.
An infrared thermometer is a surface temperature tool – period. If you’re grilling, baking, smoking or roasting you’re going to need a penetration probe to tell you the internal temperature of the food you’re cooking. An infrared will only give you the surface temperature of the food, and depending on your optical range, the temp of the surrounding grill, skillet, oven, etc.
It would be a poor indicator of actual temperature. They’re good if you need the approximate temperature of something, but not for getting a precise temperature.
Infrared thermometers work by telling you how “bright” the material is from the light energy it’s emitting. It’s pretty much how we can see how bright visible light is. Infrared thermometers are doing the same thing in the infrared spectrum. But as you might have experienced from light bulbs, you can’t always know how hot a bulb is from how bright it is. An incandescent and LED light may be the same brightness, but the LED bulb will be much cooler. If you needed to know precisely how hot the bulb was, you’d have to have a thermometer touching the bulb. With something like heating sugar for candy making where you have to hit a precise temperature, an infrared thermometer would not work very well. It would be seeing the heat “brightness” of the sugar, pot, and stove, all of which emit heat light at different levels. With practice you might be able to use it to know when the sugar is getting close to the right temp, but you’d need to use an actual thermometer to get the sugar to the precise temp. With oil, it might be reasonable enough since there’s a larger usable temperature range. But you’d have to use both the infrared and regular thermometers at first so you can figure out the infrared temp for the oil temp you need.
Is your old thermometer the glass kind? Have you considered getting a digital one with a metal shaft you insert in the oil? It should just wipe off on a paper towel or sponge.
They were kind of a trendy kitchen gadget a while back. I got one and tried it out. I found it basically useless for the reasons noted above. I got rid of it.
I have both a Thermapen like the one Dewey_Finn linked to, and a Etekcity 630 infrared thermometer. It looks like they don’t make the 630 any more, but there are similar Etekcity models for about $20 to $30.
The Thermapen is very accurate and fast. It reaches a reading in about 1-2 seconds. In boiling water, it consistently reads in the 211-212 F range. You just insert the tip of the metal probe into the material to be tested, so there’s really no problem cleaning it. You could even scrub the tip with steel wool if you had to. I’ve not used it for a pot of oil very much, but I use it a lot for meat and boiling water. It is awesome.
I use the Etekcity for things where I can’t insert the Thermapen, like an empty pan, or a pan with just a few teaspoons of oil in it. It projects a laser dot that shows you the exact point that it’s measuring. I haven’t experimented to determine its accuracy, but it seems pretty precise. That is, if I scan the same object multiple times, I get close to the same reading. If I scan a pan with a little oil in it, the bare part of the pan reads higher than the part covered by oil, which you’d expect. I mostly use it to determine if an empty pan is hot enough for searing or something like that, but I haven’t used it where the exact temperature is critical. The instructions warn that it can be inaccurate when pointed at a reflective surface, but I’ve found that even in a stainless steel skillet, it seems pretty good.
Ok, I just did an experiment. I boiled water in a stainless steel pot, and measured it with both the Thermapen and the Etekcity. I’m a couple of hundred feet above sea level, so it should be just a tad under 212. The Thermapen measured 211.4 and the Etekcity measured 199.5.
Thanks for doing the experiment. That a good example of potential issues with an IR thermometer. For the OP, if you always used the same pot and same kind of oil, you could figure out what IR reading indicated the temp you wanted. But if you used a different pot, the reading might be different.
Also, another issue is that it wouldn’t work well when food is in the oil. Getting a reading of pure oil will be pretty consistent, but food will radiate IR at highly variable rates. The IR thermometer will vary wildly from actual temp during the frying process. In that situation, it’d probably be better to get a reading by pointing the thermometer at the outside of the pot rather than at the oil.
I do have one of these, and I’ve used it for oil in the past. I think I won’t venture with an infrared thermometer, based on everyone’s advice here, and just use the digital one from here on out. I believe it’s time to consign the old candy/oil thermometer to the trash.
Before you throw out the old thermometer, you might compare results from it and the digital one. Do they give similar results?
I’d get the Thermapen standalone and the remote Thermapen with the sensor on a cord that leads to a unit that has an alarm. I got the latter on sale, but I can’t remember where or when, possibly their own website. I haven’t calibrated either, but both read ice water as ~32 and boiling water ~212.
I use a Thermapen in oil without problem.
I also have a thermapen, and i love it. And yes extremely easy to clean.
I’ve also invested in some Bluetooth digital thermometers that you can insert into a piece of meat and leave them there while it cooks, checking your phone or its base to see the internal temp. But they aren’t what you want for frying. I also have a liquid thermometer that i can clip to a pot, but the thermapen is fast enough that I’ve stopped fussing with those. (I had some bimetallic can’t thermometers, too, but i tried calibrating all my thermometers one day, and they were both slow to adjust and inaccurate. So I threw them away.)
FWIW, if you’re buying a new one, you want the Thermapen ONE. Not only because it’s quicker and more accurate, but more importantly, it takes AAA batteries, not CR2023 or whatever those quarter-sized flat ones are that the older Thermapens use.
Makes changing batteries trivial- I’ve always got AAA batteries on hand, but I don’t necessarily have CR2023 batteries.
As far as candy thermometers go, the OXO one is pretty good.