Marlene Parrish - What Einstein Told His Cook 2

Essential oils can be obtained in pure form by steam distillation (boiling the crushed plant material in water and condensing the mixed oil and water vapors), or by extraction into cold fat ( enfleurage ), hot fat (maceration), or volatile organic solvents that can be evaporated away.

If an essential oil is to affect our senses as a flavor or fragrance, it must consist of small, light molecules (with molecular weights of less than about 300 or 400) that can float through the air and reach our noses. These airborne molecules can enter our upper nasal passages, either directly through the nose or through the back of the mouth when we eat the spice. In the upper nasal passages the molecules lock onto olfactory receptors, which fire nerve cells to generate a smell signal. These signals are interpreted in the cortex of the brain, along with taste signals received from our taste buds, to produce the overall sensation of what we call flavor. Although we habitually localize flavor in the mouth, anywhere between 70 and 85 percent of the flavor of our foods is contributed by our sense of smell.

Many essential oils are chemicals called terpenes , a class of unsaturated hydrocarbons. Some examples are menthol in oil of peppermint, limonene in orange and lemon oil, and zingerone, which (no kidding) puts the zing in ginger.

A funny coincidence? No. Our English name ginger comes to us via a tortuous path from singivera in Pali, the religious language of Buddhism, to the Greek zingiberi , the Latin zingiber , and the Old English gingifer . Hence its species name Zingiber officinale and the name of one of its main pungent components, zingerone. Our slang word zing , meaning zest, may have a consequential origin.

And before you ask, the distilled alcoholic beverage we call gin has an entirely different origin. Its name comes from its predominant flavoring agent, the juniper berry, called genever in Dutch. The beverage was invented “for medicinal purposes” (wink) by a seventeenth-century professor of medicine at the University of Leiden in Holland.

THE FOODIE’S FICTIONARY:Essential oil—WD-40

HOT, HOT, HOT!

I have always wondered about the words hot and spicy with reference to the tastes of peppers and other spices. For example, why is black pepper “peppery,” while chili peppers are “hot” and ginger is “spicy”? Are the chemicals that cause these sensations all the same?

No, those different sensory effects are caused by several different chemical compounds. (See Table 6, chapter 8.)

It would be much neater if we had individual descriptive words for each of these sensations, because they are indeed all different. Instead, we apply the words hot , peppery , spicy , pungent , piquant , biting , zingy , and sharp almost indiscriminately to all. But black pepper, chili peppers, ginger, mustard, horseradish, and wasabi are all distinguishable from one another by their distinctive brands of what I’ll generically call pungency, from the Latin pungere , meaning to prick or puncture.

The French piquer and the Spanish picar , meaning to prick or sting, give us the word piquancy , which is often used interchangeably with pungency but has the slightly broader connotation of an agreeable tartness or zest. A sauce, for example, may be piquant because of the pungent pepper it contains.

But “hot” spices give us much more than their “heat.” Like all foods, they have their own complex flavors. Different hot chili peppers, which are so often characterized simply by their relative heats, contribute unique earthy, fruity, smoky, sweet, or flowery nuances to our dishes. Mexican cuisine excels at using different types of chili peppers in dishes that will benefit from their different flavor profiles.

Let’s consider some of the “hot stuffs,” one at a time.

Black pepper comes from the Piper nigrum plant, whose species name, suitably enough, is Latin for “black pepper.” When the plant’s berries are picked almost ripe and dried in the sun, enzymes turn them dark and they shrivel into our familiar black peppercorns, with their softly pungent flavor.

Green and white peppercorns are the same berry, but picked and processed differently. Green peppercorns are picked soft and unripe, then either dried or pickled in brine or vinegar, in which state they are often used instead of (and occasionally confused with) capers. White peppercorns are picked when ripe and red but then are allowed to ferment. Softened by the fermentation, the outer layer of skin can be washed off to expose the pale seed within. Alternatively, the outer skins of black peppercorns may be removed mechanically to uncover the white seed. After being dried, white peppercorns are somewhat less exciting than black ones, but they come in handy when you don’t want to add black specks to a white sauce.

The pungent chemical in these true pepper berries is piperine , the main aromatic ingredient released when the peppercorns are cracked open. As this flavorful oil slowly evaporates, the cracked or ground pepper loses its pungency. That’s why every recipe worth its salt and pepper specifies that the pepper be “freshly ground.”

In quite another category, the fiery-hot “peppers” discovered in the New World by Columbus and other Spanish explorers (yes, I know he was Italian, but Spanish pesetas were footing the bill) are not real pepper because they are not from the Piper nigrum plant. They are members of the Solanaceae family of plants, specifically, varieties of Capsicum annuum . A cynic might suspect that the explorers named these fruits pimiento because real pepper ( pimienta in Spanish) was such a valuable spice in Europe at the time that a little stretching of the truth might bring a better price back home. The explorers also called them chile and ají after their Aztec and Taíno Indian names, and the world has been confused about what to call them ever since.

Here’s a quick rundown on this bewildering state of affairs.

In contemporary Spain, the capsicums are still called pimientos , while in Mexico they are still called chiles . But in other Latin American countries they are called ají , not to be confused with ajo , which is garlic. The British changed chile to chilli , while in the United States we spell it chili , reserving the word pimiento for another capsicum species, the sweet bell pepper, except that we sometimes spell pimiento pimento , not to be confused with pimenta , the tree from which we get allspice berries, which were so named because they taste like a combination of cloves, cinnamon, and nutmeg. (Got all that?)

The essential oils in chili peppers contain chemicals ( alkaloids ) called capsaicin (cap-SAY-uh-sin) and dihydrocapsaicin plus a few closely related compounds, all collectively known as capsaicinoids . These are the burning, pungent components of hot chili peppers. About 80 percent of the capsaicinoids reside in the placenta, the fleshy ribs that fasten the seeds to the walls, not in the seeds themselves, as is commonly believed. Because of the way the seeds are attached, cooks who habitually scrape away “the seeds” with a spoon or knife blade have unwittingly been removing the real culprits, the ribs.

Capsaicinoids are odorless and are not detected by our noses or taste buds; the true flavors of the various capsicum fruits are contributed by other chemicals, just as in nonpungent fruits. Instead of being tasted or smelled, the capsaicinoids stimulate nerve endings in our skins and mucous membranes, specifically those of the trigeminal nerve, which among other jobs conveys sensations of pain and heat to the brain from the face, mouth, and nose. Hence, our brains persuade us to call these fruits “hot” and their pungency “heat,” and even to sweat when we eat them.