What, Exactly, are Herbs?Sunday, April 1, 2012
And how are they different from "spices?" It would be wonderful to have simple and straightforward answers to these questions but, unfortunately, no such answers exist.
The term "spice" doesn't even exist for botanists. And the adjective "spicy," like "hot," can refer to so many different sensations that it no longer serves a useful descriptive purpose. The word "herb" means too many different things to different people. Botanically-speaking, herbs are non-woody vascular plants that die or waste away after flowering. For cooks and gardeners, that definition is useless.
Gardeners know that some "herbs" (rosemary, sage and thyme) become woody with age, and don't "waste away" -- and laurel (bay leaves) are picked from an actual tree. Cooks distinguish herbs and spices by the parts used: "herbs" are foliage or flowers; while "spices" come from bark, seeds, or roots. In practice, "herbs" are grown in our gardens, while we import spices -- usually from the tropics.
Any set of rules we choose is bound to be plagued by exceptions. Mustard and coriander seeds are treated as spices, but they thrive in our gardens, and their leaves are used like "herbs." Fresh young mustard leaves serve as salad herbs, while older leaves are slowly cooked pot-herbs. We sprinkle cilantro sparingly, as a fresh herb, while Vietnamese toss so much on their dishes that it's practically a salad. Thai cooks treat leaves, stems and roots of cilantro as distinct ingredients… and rarely use the seeds.
We think of cloves as "spice," yet they are the unopened buds of flower, which -- by some definitions -- suggests "herb." Europeans only know clove in this form, but Indonesians use leaves, twigs, and bark. Various parts of the clove tree provide seasoning, food, perfume -- and even cigarettes called kretek -- all made with one or more parts of the tree. Eurocentric "spice" seems wholly inadequate when seen from the perspective of the Indonesians who harvest it.
While most of us think of cinnamon only as a spice (the inner bark of a tropical tree), the ancient Greeks and Romans took a broader view. They imported vast quantities of leaves, called phyllon and malabathrum, from a tree that is closely related to the one gives us cinnamon. These leaves have a stronger cinnamon presence than the bark, so perhaps our question should be, "why did cooks stop using these leaves?"
One answer is that they didn't -- they're still commonly used in the cooking of South Asia (Bhutan, India, and Nepal).
Our distinction between "herbs" and "spices" is an accident of geography, history, and contemporary modes of transportation. Those we call "herbs" have been grown, historically, in European gardens. Before the Age of Exploration, "spices" could only be obtained only through a series of intermediaries, who preferred to keep the knowledge of their sources proprietary. These sources were so mysterious that Europeans believed that they grew only in the Garden of Eden. Cinnamon, cloves, ginger, and pepper were imported from distant lands, on the backs of camels trudging along secret spice routes, or – later -- on very small ships. The costs imposed by the spice traders, and the dangers they faced along the way, forced them to choose only the most densely-flavored parts of tropical plants. Handling huge volumes of leaves and twigs was simply not cost-effective.
This is excerpted from Herbs: A Global History, a new volume in Reaktion's Edible Series of single-topic books on food and drink. It's scheduled for publication later this month, but can be pre-ordered in hard cover or for kindle.