TPM stands for Total Polar Materials (sometimes called Total Polar Compounds), a measure of how much frying oil has broken down. As oil is used at high heat, it changes chemically and produces polar compounds. The more the oil breaks down, the higher the TPM %. The Cooking Oil Tester (TPM) gives you this figure in seconds, which is far more reliable than judging oil by its colour or smell. Degraded oil affects the taste and quality of fried food and, past a certain point, should not be used, so knowing the TPM helps you change oil at the right time — not too early, and not too late.

The probe has a sensor that measures the polar compounds in the oil and turns that into a TPM %. A separate sensor reads the oil temperature at the same time. Because both the temperature and how deep you hold the probe affect the result, good technique matters, and the tester needs an occasional calibration check to stay accurate. The tester connects to the Squizify app over Bluetooth so readings can be recorded against your daily checks.