Chilli and Heat: Where It Lives and How to Take It Back

Heat is not a taste

The tongue has receptors for sweet, salty, sour, bitter and savoury. It has none for heat. What capsaicin triggers is TRPV1, a pain receptor whose real job is detecting temperatures above about 43C. Your brain reads it as a burn.

That is why spicy food feels like it hurts pleasantly, why cooling the dish does not reduce the heat, and why you acclimatise with practice. It is a different system from the other five.

It lives in the white pith, not the seeds

Capsaicin concentrates in the placenta — the white pith the seeds are attached to. The seeds themselves carry almost none.

Deseeding does reduce heat, but only because the pith comes away with the seeds. To do it properly, scrape the white pith out with the tip of a knife. Carefully picking out seeds while leaving the pith accomplishes very little.

Water does not help

Capsaicin dissolves in fat, not in water. Drinking water spreads it around your mouth without removing any of it.

What does work:

• Dairy. Casein in milk binds capsaicin and carries it off. That is why India serves lassi and Thailand serves coconut milk alongside.
• Fat and oil, which capsaicin dissolves into.
• Sugar, which dampens the pain signal itself.
• Alcohol works in principle, but not at drinking strengths.

Chillies are not ranked on one axis

Sorting varieties by heat alone will ruin the dish.

• Kashmiri chilli is for colour. It is mild and deeply red, which is why three tablespoons go into rogan josh or vindaloo and the result is still gentle.
• Korean gochugaru brings aroma and a little sweetness. Substituted one-for-one for Kashmiri you get less colour and more perfume.
• Thai bird's eye is for heat. What two or three of them do in pad kra pao is hard to reproduce with anything milder.
• Dried and fresh chillies are different ingredients. Drying removes the green, grassy note and creates dried-fruit sweetness and smoke. Swapping one for the other is not substitution; it is a different addition.

Oil is what opens them

Capsaicin and the red pigments are both fat-soluble, so chilli slaked in water only half opens. Thirty seconds to a minute in oil turns the whole panful red and changes the aroma entirely (blooming spices).

But ground chilli burns in thirty seconds. That is why rogan josh drops the heat before the chilli goes in, and why malatang keeps its oil cool. Burnt chilli stays bitter through two hours of cooking.

When it has already gone too far

Capsaicin does not cook off. You cannot boil heat away, and there are only four moves.

• Add fat: coconut milk, cream, butter, yoghurt. The most reliable of the four.
• Add sugar. A teaspoon measurably lowers perceived heat.
• Add acid. Lime or vinegar does not reduce the heat but does distract from it.
• Add bulk — not water, but something absorbent like potato, tofu or rice. Water alone dilutes everything except the heat.

Which is why a too-hot tteokbokki is better served by sugar and fish cake than by a splash of water.

Handling them

Since capsaicin does not rinse off with water, hands that have prepped chillies will still transfer it to your eyes after a wash. Rub oil into your hands first, then wash with soap. For any quantity, wear gloves.