Sesame Oil

Toasted and untoasted are different ingredients

Two quite different oils are sold as "sesame oil".

• Toasted sesame oil: the dark brown oil of Korea, China and Japan, pressed from roasted seeds. Strongly aromatic, with a smoke point around 175C. It exists for its smell.
• Untoasted sesame oil: the pale yellow oil used across the Middle East and India. Almost no aroma, smoke point above 200C, and usable as a cooking oil.

"A teaspoon of sesame oil at the end" means the first. "Fry in sesame oil" means the second. Swap them and both dishes fail.

What "finishing oil" means

The aromatics in toasted sesame oil are highly volatile and simply leave when heated, and its low smoke point means it turns bitter at wok temperatures.

So the order is fixed: kill the heat, then add it. The sesame oil in japchae and bibimbap goes in after the cooking, and in a cold dressed dish like sigeumchi namul or kongnamul muchim it carries the aroma from the start (heat control).

To keep its scent in something fried, cook in neutral oil and add a swirl of sesame oil at the end.

Use less than you think

A single teaspoon dominates a plate. Overdo it and everything else disappears behind it, and it grows more assertive as the dish cools.

Too little is fixable; too much is not. Add half, taste, then add more.

Choosing

• Read the ingredients. Blends cut with soybean oil are common even when the label says sesame in large type. 100% is what makes the difference.
• Darker means more heavily roasted. Dark suits dressed vegetables; lighter suits finishing a soup.
• Buy small bottles. A large one oxidises before you finish it.

Storage

• Refrigerate after opening. It is high in unsaturated fat and oxidises quickly at room temperature.
• Work on three months once open; refrigerated, a little longer.
• If it smells rancid — like old crayons — throw it out. That smell transfers directly into the food and heat does not remove it.

Substitutes

• Perilla oil is not a substitute. Grassier, and it oxidises much faster.
• In a pinch, sesame seeds toasted in a dry pan and coarsely ground point in the same direction.
• Untoasted sesame oil used in place of toasted contributes no aroma at all.