“Calibrate your dome thermometer regularly. To do this, take the thermometer out of the dome and put a pair of pliers on the nut under the dial. Place at least 1 inch (1.3 cm) of the thermometer tip into boiling water and see whether it reads 212°F (100°C). If it doesn’t, hold the dial with a cloth and rotate it until it is at 212°F (100°C). It may take a couple of tries before you get it calibrated.”