Frying oil can go rancid due to many factors, including overheating, prolonged use, and contamination from foods. The best indicator of oil quality is the percentage of Total Polar Compounds (TPC) which accumulate during usage.  23-25% TPC is typically considered the point at which oil taste and smell are considered rancid and should be replaced.  The recommended method by the American Oil Chemists' Society is time consuming and requires a full analytical lab.  Our novel method uses a proprietary dye and known standards allowing for accurate results in less than 5 minutes and at a fraction of the cost.

This kit is designed to quickly measure the change in polarity of a cooking oil due to oxidation and hydrolysis from heating.  It is based on the properties of a merocyanine dye that undergoes a significant color change as the percentage of TPC increases.