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Smoke point

The temperature at which a fat starts to break down visibly, and why it matters less than it is said to.

What it is

A fat that is smoking is decomposing: free fatty acids are breaking off and volatile products are leaving, taking flavour with them and leaving acrid notes behind.

Why it works

Smoke point is not a fixed property of an oil but of that particular oil now. Refining raises it; free fatty acids lower it, and they accumulate every time the oil is heated, so used frying oil smokes earlier than fresh. An unrefined oil with a low smoke point is a poor choice for deep-frying and a fine one for a dressing.

When to use it

Choosing a fat for frying, roasting or dressing.

What goes wrong

Treating a published figure as exact; reusing frying oil until it smokes at frying temperature; using an expensive unrefined oil for high heat, where its flavour is destroyed.

Meridian cooking encyclopedia โ€” Watchman Productions

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