Why mint feels cold
Peppermint is rich in menthol, which activates TRPM8, a receptor that normally reports cool temperatures. Your brain registers cold even though nothing in your mouth got colder. Chilies do the same with heat.
Real cooling versus nerve cooling
Some cooling is real. Sweeteners like erythritol and xylitol absorb heat as they dissolve, so they actually chill your tongue. Menthol cooling is a nerve signal. Peppermint and spearmint also differ: spearmint is mostly carvone and contains far less menthol.
Test yourself
Questions from the interactive lesson, with the answer and the why.
Does peppermint candy actually lower the temperature of your tongue?
No, menthol only triggers a cold-sensing receptor. The cool feeling is a nerve signal, not a real temperature drop.
True or false: Menthol cools your mouth by absorbing heat, like ice does.
False. Menthol triggers a receptor. It doesn't draw heat from the mouth the way ice does.
Fill the blank: Menthol switches on the cold-sensing receptor ___, so the brain reports cool.
Menthol switches on the cold-sensing receptor TRPM8, so the brain reports cool. TRPM8 is the receptor that reports cool temperatures.
What went wrong? You stir fresh spearmint into brownie batter, expecting an icy peppermint chill. You get a mild herbal flavor instead.
Spearmint has far less menthol than peppermint. It is mostly carvone, so the cold receptor barely fires.
True or false: Breathing in after a mint makes the cool feeling stronger.
True. Air flowing over menthol-coated tissue strengthens the cold sensation, so inhaling feels icier.