Thermometer Calibration
Every
year you should verify the accuracy of your kitchen thermometers. The
new and old oven-proof, instant-read and digital thermometers should be
calibrated. Ideally, these thermometers should be calibrated when first
purchased as well as checked for accuracy before the holiday rush.
Accuracy can be altered if the thermometer has been exposed to extreme
temperature changes or has been dropped. Here are two simple ways to
test for accuracy.
Ice Point Method
In a cup prepare a 50/50 mixture of ice and water to form a water slush. Place at least two inches of the thermometer stem into the cup, making sure the sensing tip is fully inserted. The tip should not touch the bottom or side of the cup. Wait about five minutes or until the needle is steady and verify the needle registers 32 degrees F. If the needle does not register 32 degrees F, an adjustment should be made by turning the small nut on the back end of the dial.
Boiling Point Method
Fill a pan with about three inches of water and bring to a rolling boil. Place at least two inches of the thermometer stem into the water, making sure the sensing tip is fully inserted. Use caution to avoid burns. The tip should not touch the bottom or side of the pan. Wait about one minute or until the needle is steady and verify the needle registers 212 degrees F.
(NOTE: Water boils at a lower temperature at higher altitudes. For every 500 feet above sea level, subtract 1 degree. (for example, 202 degrees F at 5,000 feet.). If the needle does not mark the boiling point, an adjustment should be made by turning the small nut at the back of the dial.
Digital Thermometers
Digital thermometers usually have 2 screws to adjust freezing and boiling. Peel the back label off to expose the adjustment screws. Use the ice-point and boiling point methods.
