You have a thermometer in a drawer in your kitchen, right? You may even have separate ones for meat, for candy, for frying, or just for tempering chocolate. You probably assume every one of them is accurate, right? But, how do you really know? You can test them.
Speaking of testing…did you know you should check the thermometer’s accuracy when it’s brand new? You should also recheck it every six months or so…especially if you drop or otherwise traumatize it or haven’t used it in a while. I check mine whenever I’m not sure it’s telling me the correct temp. For instance, when I check meat on the grill and it registers the same temp as the last time I checked it. Of, if it looks like my water is boiling and the thermometer only reads 200.
So how do you check it? You could use boiling water or an ice bath; doing both is not a bad idea either.
To test in boiling water:
Water at sea level boils at 212° F or 100° C. Bring a pot of water to a rolling boil and place your thermometer stem at least one inch deep in the pot of water. Don’t let it touch the sides or bottom of the pot, however. Probably within a minute or even less, your thermometer will register the temperature. Here’s a tip to avoid scalding your hand…use tongs to hold the thermometer. Your thermometer is accurate if it registers 212° F or 100° C. If you don’t live at sea level; check online to see what temperature water boils at your elevation. This is important as it could vary greatly, depending on where you live.
To test in an ice bath:
Water freezes at 32° F or 0° C. For this testing, you need as much ice as possible in a glass of water. Set that glass inside a larger pan or bowl and fill your glass to the top with ice, preferably crushed. Cubed ice might not give you an accurate reading as it doesn’t create the frozen sensation you need for this test. Pour cold water over the ice to the rim of the glass, making sure you still have a full glass of ice. You may need to add more. Place your thermometer stem at least one inch deep into the ice water without letting the stem touch the glass. Wait for the thermometer to register; again a minute or less. The thermometer is accurate if it registers 32° F or 0° C.
After all, you don’t want your cookies, bread, or meat overdone, under cooked, or less than perfect.