Chocolate Mint Day

What the day is

Chocolate Mint Day is observed on February 19. The mint half of the pairing is the more surprising ingredient.

Origin and background

Peppermint is a hybrid, the cross of watermint and spearmint, and it is sterile. It does not breed true from seed and in practice barely sets viable seed at all, so every peppermint plant in cultivation descends by cutting and root division from the same original hybrid stock. Like the named apple varieties, it is a clone maintained by propagation rather than a species reproducing itself.

The two mints also taste different for a specific chemical reason. Peppermint's dominant compound is menthol, while spearmint's is carvone. Only menthol triggers the receptor that detects cold, which is why peppermint produces that cooling sensation and spearmint, despite tasting recognizably minty, does not. Confectioners choose between them accordingly: the cooling effect belongs to peppermint alone.

The pairing with chocolate works partly because menthol's cooling runs against chocolate's fat melting at body temperature, so the two sensations arrive together and neither masks the other.

In the garden, mint's reputation is deserved. It spreads by runners that travel underground and surface some distance away, and a mint planted in open ground will colonize a bed within a couple of seasons. The standard remedy is to grow it in a buried container with the rim above soil level, which blocks the runners.

All mints share the family's square stems, an identification feature reliable enough to be worth knowing, since the whole family, including basil, sage, rosemary and thyme, has them.

How to take part

• Taste peppermint and spearmint side by side and notice only one goes cold.
• Grow mint in a pot, or in a sunken container if you want it in a bed.
• Feel the square stem on any mint plant.
• Steep fresh leaves rather than using a bag. The difference is considerable.
• Try dark chocolate with mint rather than milk, where the cooling reads more clearly.