Because accuracy is critical for successful candy making, it is a good idea to calibrate your candy thermometer.
Here’s how to do it:
- Insert your candy thermometer into a pot of water, and bring the water to a rolling boil. At 7,000 feet above sea level, the boiling point for water is 199 º Fahrenheit. Use this calculator to determine the boiling point of water at your elevation.
- Leave your thermometer in the water for five minutes to give it time to get an accurate reading. Make sure that the base of the thermometer is fully immersed in the water, and that it is not touching the bottom or sides of the pot—this can give a false reading.
- Inspect the temperature on your thermometer, making sure that you are eye level with the thermometer and not looking at it from an angle. Is it 199 º F? If so, your thermometer is accurate!
- If your thermometer is off by a few degrees, no big deal. This is good information to have. Take this temperature difference into account when doing all future candy making with the thermometer. For instance, if your thermometer registers 210 º F when inserted in boiling water, you now know that your thermometer reads temperatures 11 degrees hotter than they actually are. If you have a recipe that calls for a temperature of 220 º F, you know you need to add 11 degrees and reach 231 º F on your thermometer to get your candy hot enough.
- If you find that you are regularly getting drastically different results from your calibration, that means your thermometer is no longer reliable and it is time for a new candy thermometer.
- Perform this test on a regular basis, to ensure that your conversion is still accurate.