Candy canes are by any measure a strange sweet. Brittle and unwieldy, theirs is a shape of candy you only see once a year — to signify … a shepherd’s crook? A crutch to get you through the loneliest season? Or just a convenient shape to hang from a fir branch?

Stranger still is the flavor: peppermint. This invigorating tidal wave of a flavor is as much a sensory experience as a taste — one that defies the usual holiday hat trick of sweet, fatty, and cinnamon-y. What is the secret to this beloved treat? You can find an answer in its chemical composition, a receptor on our tongues, and evolutionary tactics.

Peppermint (Mentha piperita) is actually a hybrid plant of two other kinds of mint: watermint and spearmint. Its dark-green, pointed leaves can be used freshly picked, dried, or made into a flavorful oil.

But beneath the surface, the most important component of peppermint is menthol, an organic compound found in mint plants. Peppermint is made up of 40 percent menthol, which is largely responsible for that sweet, slightly spicy taste and cooling sensation in peppermint-flavored sweets and products. (Menthol can also be made synthetically. )

While peppermint is often used as a flavoring in cooking and baking, menthol can be used on its own in medicinal products, like cough drops and nasal inhalers, or added to cosmetics and cigarettes.