If measuring the temperature of a thin food, such as a hamburger patty or boneless chicken breast, the probe should be inserted sideways with the sensing device in the very center of the patty. Bimetallic-coil thermometers measure temperature by averaging the temperatures along the metallic coil area. Inserting the thermometer through the center takes advantage of this by averaging the temperature of the center of the food. Since the semiconductor is in the tip, thermistors can measure temperature in thin foods. As with the bimetal instant read thermometers, thermistors should be placed in foods towards the end of cooking time to check for final cooking temperatures.
Thermocouple thermometers are the fastest reading of all thermometers.
They can show a final temperature in seconds on a digital display. They have very small tips and can accurately measure the temperature of very thin foods, depending on the size of the probes. Thermocouples measure temperature at the junction of two fine wires located in the tips of the probes. Since thermocouple thermometers respond so rapidly, the temperature can be easily read in a number of locations to ensure that the food is thoroughly cooked. This type of thermometer is used primarily in retail or foodservice kitchens, but consumer models are now being marketed.