Other heat

When we say «spicy» we think of the chile, but capsaicin has plenty of cousins. Different molecules, different receptors and, most curiously, different ways of burning (or tingling). This is the map of the world’s other fires.

Black pepper: the heat Columbus was after

The culprit is piperine, which triggers the same heat receptor as capsaicin, although it burns far less. There is a nice historical twist: it was precisely the hugely expensive spice Columbus was chasing when, by accident, he stumbled onto the chile. Black, white and green pepper are the same berry at different stages of ripeness and processing. And it has even more exotic relatives, like long pepper.

Ginger: the heat that warms

The gingerol in fresh ginger gives a warm, enveloping pungency, very different from the chile’s sharp edge. The fascinating part is that, when dried or cooked, gingerol turns into shogaol, an even hotter molecule: that is why dried ginger bites more than fresh. From the same botanical family come galangal and other aromatic roots.

The mustard family: the burn that goes up your nose

Mustard, horseradish and wasabi share a weapon: allyl isothiocyanate. Its trick is that it is volatile, so instead of staying on your tongue it shoots up your nose and sinuses, and disappears almost as fast as it arrives. That is why, against this kind of heat, holding your breath helps more than drinking water.

Sichuan pepper: it does not burn, it tingles

Here the rules change. Sichuan pepper does not burn: it produces an electric, numbing tingle, like a weak battery on your tongue. The culprit is hydroxy-alpha-sanshool, and a University College London study even measured that vibration at around 50 Hz (similar to an electric toothbrush). It is the «má» (numbness) of málà, the numbing-and-spicy blend of Sichuan cooking, where it teams up with the chile itself.

Other fires around the world

• Grains of paradise (or Guinea pepper): African cousins of pepper and ginger, with a pungency carrying hints of citrus and cardamom.
• Garlic and onion: allicin does not just bite, it also makes you cry; it triggers the irritant receptor, the same one wasabi sets off.
• Cinnamon: its cinnamaldehyde is behind that sweet warmth you notice at the back.
• The electric button (jambú, Acmella oleracea): a flower that numbs the mouth and sets off salivation thanks to spilanthol, a molecule related to sanshool.

The science: why such different things «burn»

Not all heat speaks the same language. Capsaicin, piperine and gingerol activate TRPV1, the heat receptor (hence that burning feeling). The isothiocyanate in wasabi and the allicin in garlic activate TRPA1, the irritant one (hence the assault on the nose and eyes). And sanshool is not even about heat: it fools the touch receptors. A single word, «spicy», for completely different mechanisms.

Chile is still the undisputed king of spice but, as you can see, it does not reign alone. The world is full of ways to burn, and each one deserves its place at the table.