Herbs are leaves, spices are everything else
Cooks usually call the leaves of a plant a herb and any other dried part a spice. BASIL, THYME, PARSLEY, SAGE, ROSEMARY, OREGANO, DILL and MINT are herbs. Basil, thyme, sage, rosemary and oregano all belong to the mint family, and all have the square stems typical of it. CINNAMON is the inner bark of a tree, peeled off and rolled into quills as it dries. A CLOVE is a flower bud picked before it opens. GINGER and TURMERIC are underground stems, and CUMIN and FENNEL are seeds. Turmeric gives curry powder and American mustard their bright yellow colour. One plant can give both: CORIANDER leaves are a herb, and its seeds are a spice.
NUTMEG is the seed of a fruit that grows on a tree, and the lacy red covering around the seed is a second spice, called mace.
An island swapped for Manhattan
For centuries, nutmeg and cloves grew only on a handful of small islands in what is now Indonesia, and by the time they reached Europe they were among the most valuable goods in the world. In the 1600s the Dutch and English fought over them. In 1667, at the end of a war, the two countries signed a treaty in which England gave up its claim to the tiny nutmeg island of Run, and the Dutch gave up their claim to a colony in North America called New Amsterdam. The English renamed it New York.
The search for a sea route to the spice islands drove much of the European exploration of the 1400s and 1500s. Our explorers page covers the voyages. Black PEPPER was once so valuable that it could be used to pay rent; a peppercorn rent now means a tiny, token payment.
The most expensive spice in the world
SAFFRON is the red threads from the middle of a purple crocus flower. Each flower has only three, and they must be picked by hand, so it takes around 150 flowers to make a single gram. That makes saffron the most expensive spice by weight. The town of Saffron Walden in Essex took its name from the crocus fields that once surrounded it. CARDAMOM and vanilla are the next most costly.
Cheaper spices were sometimes passed off as saffron. In medieval Nuremberg, merchants caught selling fake saffron could be burned along with their fraudulent goods.
How hot is a chilli?
A CHILI gets its heat from a chemical called capsaicin, which tricks the nerves in the mouth into sending the same signal as real heat. In 1912 an American chemist called Wilbur Scoville found a way to measure it, by diluting chilli extract until tasters could no longer feel it. A sweet pepper scores zero on his scale, a jalapeño a few thousand, and the hottest chillies more than two million. Birds cannot feel capsaicin at all, so they eat the chillies and spread the seeds, while mammals leave them alone.
PAPRIKA is made from dried, ground red peppers, some sweet and some hot, and is the national spice of Hungary. A BAY LEAF goes into a stew whole and comes out at the end.