The Chemistry Behind the Heat: Why We Love Spicy Food

Emily Cho '27 • Nov 5, 2025

The demand for spice has grown exponentially global: reflected  in the long waiting lists at Haidilao, a renowned hot pot chain, as well as the viral “spicy noodle challenge” on social media spicy foods have evolved beyond a mere culinary trend. Korea, one of the biggest exporters of spicy instant noodles, namely Buldak Ramen which are now available in over 100 countries, have surpassed nearly $100 million in revenue every month. But why is spicy food so irresistible despite the pain, and what makes us keep returning for more?

What Is Spiciness, Really?

Contrary to popular belief, spiciness isn’t a taste. Unlike sweetness, sourness, or umami, which are perceived via taste receptors on our tongue, spiciness is a tactile sensation–a feeling of heat and pain induced by certain compounds like capsaicin. These compounds activate the sensory neurons known as polymodal nociceptors, the same receptors that respond to actual heat and injury. When triggered, the brain interprets the signal as an actual heat: producing sweat, tears, and increased heart rate to cool your body down. This biological mechanism was first discovered by David Julius, winning him the 2021 Nobel Prize in Physiology and Medicine.

The Science of Tolerance—and Pleasure

Still, many of us crave spicy food. This paradox lies in neurochemistry. When sensing pain, the brain releases chemicals like adrenaline, endorphins, and dopamine, which are chemicals responsible for relieving stress and improving mood. This is reminiscent of thrill-seeking behaviors such as bungee jumping, riding a roller coaster, or watching horror movies. Studies show that people who enjoy spicy food are more likely to engage in other adrenaline-rich activities, including gambling and adventure sports.

Why Milk Works Best for Neutralizing Spice

When your mouth is on fire, the first instinct might be to reach for a glass of cold water. However, to all spice lovers, one might notice that the burning sensation rarely cools down. Capsaicin and piperine are fat-soluble, meaning that they dissolve in fat, not water. Water can only function to cool down the molecules temporarily without dissolving them. Milk, however, contains fat with similar chemical structures to capsaicin and piperine, composed of carbon, hydrogen, and oxygen.

Different Kinds of “Spice”

There are different kinds of spicy sensations as well, depending on the compound. Wasabi and mustard, for example, contain small, light molecules called isothiocyanates, which float up to the nose and irritate the sinuses. In contrast, capsaicin from chili peppers and piperine from black pepper contain very heavy alkylamide compounds that last in the mouth longer. Finally, Menthol, a compound found in mint, can produce a refreshing, icy feeling rather than a burning sensation by activating cold receptors.