Cooking Oil FAQs
Why measure cooking oil?
All cooking oil breaks down over time. The simple act of heating and re-heating cooking oil means approxi mately doubling its oxidation (breakdown due to oxygen) rate for every 50°F increase in fryer temperature. So unless you routinely measure the %TPM levels in your cooking oil, you are never quite sure how much it has aged.
What effect do additives have?
The Testo 270 is designed for measurement of pure oils/fats. When using additives, extenders and filter aids, particularly very aqueous ones, discrepancies can occur in %TPM readings due to the substances in those additives.
Effect of water on %TPM measurements
If bubbles are coming out of the cooking oil, water is still present. Any water left in the cooking oil will significantly alter %TPM measurement results, as water itself is a very “polar” material. Consecutively lower %TPM readings mean water is still present. Wait five minutes, then test the cooking oil again.
Does filtration help reduce TPM concentrations in cooking oil?
Regular oil filtration is a necessary task that should not be avoided. It removes (depending on equipment used) both large and small particulates in the oil. And while filtration goes a long way to help clear up cooking oil, it does not totally remove the by-products resulting from the frying process. You still need to measure the %TPM of the oil to know just how much “fry-life” the oil has left.
Why not just use the “smoke point” to judge oil quality?
The smoke point is the lowest temperature of a hot oil or fat at which smoke visibly develops on the surface. As cooking oil is used, various by-products accumulate so that the oil starts smoking at lower temperatures. Many food health experts consider 338°F as a minimum smoke point. Always monitor the Testo 270 temperature readings to check the smoke point.