A high smoke point is desirable for a cooking oil. When frying, best results occur when the oil is very hot. The food is placed into the hot oil and the natural sugars caramelize and proteins denature into a thin shell which protects the food from soaking up the oil. The outside is crisp and the interior is just cooked.
When heated oil smokes, it is not just a nuisance. Besides coating your home interior with a varnish like substance, where there’s smoke there’s fire. An oil at its smoke point is closer to its flash point – the point where it will burst into flame.
So a high smoke point is one yardstick for a “good oil” If you go to the internet or the market to look for smoke points you will see something interesting. Every oil claims to have the highest smoke point.
The smoke point for a vegetable oil will vary according to the variety and growing conditions, and how the oil was produced.
The smoke you see may be impurities in the oil which are burning. Unfiltered olive oil has small bits of olive in it. When the oil is heated these bits will burn and smoke before the oil itself. A well-filtered or clarified oil will have a higher smoke point generally.