Deep frying is a very popular way to cook. Done right, the fried goods are delicious, fast served, and deliver a perfect crunch. 
However, frying oil degrades if it’s used repeatedly. The longer the cooking oil is used, the lower the quality. During the deep frying process, heat, air, and moisture are brought into the oil, which causes it to breakdown. Conversely, the lower oil quality also influences the quality of the fried food. It affects the color, taste, and texture of the dishes. So finding out when it is the right time to change the oil is crucial to ensure quality and optimal usage.
This brings every bar/restaurant operator to the same question: How exactly do we know it’s time to change the frying oil?
Guessing the Quality
It is still common for many chefs to use the sensorial determination method by comparing oil samples or deciding if they can still see the frying basket trough the oil. Oil turning darker during its lifetime is mostly caused by caramelization of sugar brought into the oil, which is not harmful nor does it influence the oil quality.
Changing the oil by schedule is also widely practiced but since the amount of food prepared, the temperature of the oil, microparticles and water added to the oil, light and air are never the same it is not a sustainable nor an accurate practice.
Getting an Idea of the Oil Quality
Measuring the free fatty acids in your frying oil with the help of testing strips is a common practice. Those single-use strips give you a small insight into the frying oil quality by measuring the FFA content. An improved determination method to the guessing by color and changing oil by schedule.
Knowing the Oil Quality
The safest and most reliable way to measure your oil quality is with the help of digital oil testers. They measure the full range of the oil quality, rather than picking just one component like the testing strips. Like in a laboratory, those testers measure the total polar material percentage in your oil, short TPM. Measurements results are shown as a numeric percentage and for simplification a colored display or light will flash like a traffic signal. All common versions of testers available are also performing a temperature check during measurement, to keep you in the optimal frying temperature range.
Picking the right time to change your frying oil is crucial for your operation. Are you changing your oil too early or too soon? Stop guessing and start knowing!
