It is important that the thermometer provides an accurate reading. Its accuracy should be check occasionally to ensure proper readings. If the temperature is not accurate, the thermometer can be calibrated. To check the thermometers accuracy, boil a small pan of water and take its temperature. The water should be 212°F (adjust temperature for higher altitudes) when the water is boiling. If it is not, on an analog thermometer, hold on to the face of the thermometer and turn the nut under the face of the thermometer with a plier. If it doesn't turn easily try using pliers to hold the face and one to hold the nut and then turn them in opposite directions. After adjusting, check the temperature of the boiling water again. Readjust if necessary. Not all digital instant-read thermometers can be calibrated so check the manufactures instructions to see if yours can be adjusted and for directions on how to do it.