Which type of thermometer is best for measuring the temperature of a roast?

The bimetallic stemmed thermometer is the best choice for measuring the temperature of a roast because it is specifically designed to accurately assess the internal temperature of large, thick foods. This type of thermometer features a metal probe that contains two different metals, which expand at different rates when heated, allowing for precise temperature readings.

When using a bimetallic stemmed thermometer, you insert the probe into the thickest part of the roast, making sure not to touch any bone, which can give a misleading temperature reading. The thermometer typically provides readings in a clear, easily readable format, which is essential for ensuring that the roast reaches a safe cooking temperature to prevent foodborne illness.

While the other types of thermometers, such as dial thermometers or infrared thermometers, have their uses, they may not provide the same level of accuracy or suitability for this specific task. Dial thermometers can be less precise, and infrared thermometers are not suitable for measuring internal temperatures, as they only read surface temperatures. The thermocouple with a penetration probe could also work, but it might be more complex and is generally more expensive, making the bimetallic stemmed thermometer the most practical and reliable choice for monitoring the doneness of a roast.