International Hot and Spicy Food Day

What the day is

International Hot and Spicy Food Day is observed on January 16. The heat it celebrates is not one of the tastes. It is a separate sensory system being triggered.

Origin and background

Capsaicin, the compound in chilies, binds to a receptor in the mouth and skin whose job is to detect genuinely dangerous heat, somewhere above about 43 degrees Celsius. Capsaicin opens that receptor directly, at any temperature, so the nerve reports a burn that is not happening. There is no tissue damage from a hot curry; the alarm is simply false. That is also why the sensation is felt on the lips and skin, which have no taste buds but plenty of the same receptors.

This explains the remedies. Water spreads the capsaicin without removing it, because the molecule is oil-soluble and not water-soluble. Dairy works for two reasons: the fat dissolves it, and casein helps lift it off the receptors. Rice and bread work mechanically by scraping and absorbing.

The plant's motive is worth knowing. Capsaicin deters mammals, whose molars destroy seeds, while birds lack the receptor entirely, feel nothing, and pass seeds intact over distance. The chili is not defending itself from everything. It is selecting its courier.

Tolerance is real and builds through repeated exposure, which desensitizes the receptors. Regular chili eaters are not being brave; their nerves respond less.

The Scoville scale, devised in 1912, originally measured how far an extract had to be diluted before a panel of tasters could no longer detect heat. Modern measurement is chemical, though results are still reported in the old units.

How to take part

• Keep yogurt or milk to hand rather than water.
• Build heat gradually across a meal. Tolerance rises within a sitting.
• Wear gloves handling very hot chilies, and never touch your eyes afterward.
• Try a chili for flavor rather than heat. Many have real fruitiness underneath.
• Remember the seeds are not the hot part. The pale pith holding them is.