A temperature reading that is off by several degrees can ruin a dish. I rely on meat/fry/candy thermometers to ensure that meats are cooked just right, jams have reached their setting point, or that oil is hot enough to fry in. In Manila, we have several food thermometers, many of them gifts from friends that know I like to cook, and I use them often. I also have independent thermometers for our ovens, which can be surprisingly mercurial, and heat unevenly and inaccurately. At any rate, these little gadgets can themselves be totally inaccurate, so here’s a quick tip I once read somewhere on how to calibrate your thermometers. Blitz several ice cubes and a bit of water in a blender, transfer the slush to a glass and plunge in a meat thermometer. It should register somewhere around 32.5 to 33.5F. Just above freezing, or melting point. If you get that reading, you have a pretty accurate thermometer, like the one up top, the first one we ever bought, have had for 10+ years and it continues to work beautifully…
Our candy or jam thermometer, however, which I have noticed on several occasions does not seem to reach the proper setting point of sugar/jam, turns out to be 10F off the mark! To find out, I put it in nearly boiling water that was transfered to a cup, and compared the temperature to already vetted first thermometer. The larger thermometer was giving me a reading that was 10F less than the smaller thermometer. Arrggh! If you want to be really accurate, you can plunge your themometer into just boiling water and you should be a reading of 212F. No need to throw out the bad thermometer, just adjust by 10F or so the next time you use it.
Finally, I tested this fancy, schmancy “Sur La Table” digital thermometer and it was quite accurate. So if you have food thermometers in your household, take a couple of minutes to make sure they are calibrated, so you don’t ruin a good roast, or burn a batch of jam… :)
13 Responses
Excellent tip, I’ve got a few thermometers at home, ‘ll make sure to test them out! Thank you again!
Thanks for the tip,MM!
Thank you, MM! We presume, at least I do, that when I buy these things, they are accurate. Thank you for opening my eyes and making me wiser. Didn’t think of checking and calibrating for accuracy and adjusting, if inaccurate.
Thank you for the tip, MM. I have gone through a few thermometers in the past and not until I followed America’s Test Kitchen’s recommendation of Thermoworks thermometers that I have finally settled on just one brand. I use their Thermapen on just about everything. This brand is truly as accurate as a thermometer can get.
Thanks for this tip.How do you calibrate an oven thermometer?
yes, Betchay, am having the same problem with my oven thermometer. Have tried calibrating several times, but it’s still not working properly.
Thanks for tip MM! This is a big help for someone like me who is still quite new in the kitchen world. =)
Off topic but calibration related, I recently checked my blood pressure on one of those Mercury Drug machines that takes 5 peso coins. The reading was 139/73 which I thought was a bit high. It so happened there was a manual bp station inside the mall, and just 5 minutes after the first check, my bp measured 110/70.
An accurate way of calibrating a thermometer is by referencing it with a mercury in glass thermometer in slushed ice water. If it does not have the same reading, then adjust the thermometer. (not the meccury in glass. That one never needs adjusting) The digital thermomters are usually the ones that always need adjusting. The other ones too if you drop if or if the adjustment gets loose. It is really easy to adjust. Just underneath the head, there is a bolt like notch that you turn with a wrench or pliers. The digital ones might need their batteries changed.
thanks, MM! will check on ours …
Thanks for the tip, MM! I should do that this summer just to make sure our thermometers are working correctly.
nice tip….gonna try it this weekend.
Great tip! Thank you, MM.