Many a chile-eater has asked the question, "What's in this stuff?" The answer is: lots of things.
Literally hundreds of flavor elements have been discovered in chiles, which explains why paprika and jalapenos smell so different. But many people have noticed that all fresh peppers smell much the same. This is because they contain 2-methoxy-3-(2-methylpropyl) pyrazine, one of the most aromatic compounds known. It belongs to the family of chemicals responsible for the aromas of browned meat and bread, and it's also found in green coffee beans and certain grapes. When wine tasters speak about finding a "bell pepper nose" in Cabernet Sauvignon or Sauvignon Blanc, they're speaking the literal truth.
On the other hand, who cares? With tears streaming from our eyes and our breath coming in gasps, what we really want to know about chiles is what makes them so hot--and what they're doing to us.
The pungent element in peppers has long been known as capsaicin, but chemists have discovered that it's actually five chemicals--all related to vanilla, oddly, though they have no odor of their own. Three of them give a rapid, spicy bite and a pungent sensation in the throat; the other two produce a long, smoldering burn in the middle of the mouth. Different chiles have different proportions of these chemicals.
Artificial cousins of capsaicin have been produced in the laboratory. None of them are hotter than the real thing, but each has its own special effects. One doesn't cause a burn at all, just sneezing.
People who are selling hot chile preparations often refer to the Scoville scale. This is essentially a measure of dilution: The score is equal to the number of quantities of water that can be added to a sample of the pepper in question and still give a taster a detectable burn. Thus a habanero pepper might get a ranking of 200,000 Scoville units. However, the test is very subjective; some taste panel members are more sensitive to pepper than others. Anyway, chiles from the same field, or even the same plant, can vary in hotness.
You should take any score of Scoville units as a rough, relative measure of hotness. Canning companies do. In order to get a consistent level of hotness in canned foods, they don't use actual chiles but a chemical extract of guaranteed hotness. Say, 1.2 million Scoville.
There are a lot of myths about chiles. An old one is that the seeds contain all the heat. Actually, the seeds aren't hot at all--it's the tissue that holds them, the "vein" (technically the dissepiment) that contains up to 90% of the pungency.
A newer myth, which has been quoted even in U.S Government publications, is that you can't kill the burn of an excessive mouthful of chile with water because the hot stuff is an oil and doesn't dissolve in water. That's wrong on several counts. For one, capsaicin is not an oil--it's a crystalline substance. And though it may not dissolve in cold water, it does in hot water.
Most important, when you burn a long time after a mouthful of hot food, it's not because the chemical is "sticking" to your mouth. It's simply because that's what capsaicin does to our nervous system. Even after the chemical is washed away, nerves in your mouth will continue to send a fire alarm for six minutes no matter what you do.
What does capsaicin do to you, apart from the burn? A total grab-bag of effects. It reduces the ability of the stomach wall to absorb fat; it also speeds food along the digestive tract. (A Chile Pepper Diet has been proposed.) It enlarges the blood vessels and decreases the ability of the blood to clot for half an hour after eating (a study done in Thailand proposed that the low incidence of thromboembolism there was due to the fact that Thais eat peppers all day). It speeds up and slows down the heartbeat randomly. It causes panting.
It's suspected of stimulating the pleasurable enzymes known as endorphins, also responsible for the famous "runner's high." What's more, the elements in the body's muscles that are affected by capsaicin are the same ones that redistribute blood flow in the muscles after violent exercise. Perhaps the serene sensation that comes over you after eating a mouthful of fire--as if you'd just accomplished something monumental, like climbing a mountain--is just your muscle chemistry talking.
And as everybody knows, capsaicin causes sweating. This has often been thought to be the reason for the popularity of peppers in tropical countries. Probably chile's cheapness and the fact that it provides a big bang for your spice buck are also important factors in tropical diets, but there is something to the idea that chiles cool you down.
Not because they cause sweating. Chile-induced sweating isn't like the sweating caused by heat. When you've eaten a chile, you sweat from different parts of the body (particularly the head), and different places on the face, for instance, than you do as a result of hot temperatures.
No, the reason for the popularity of chile in the tropics may have to do with another feature of chiles: They confuse the body's temperature regulation system. They cause a dramatic fall in body temperature, and they also make you less sensitive to the temperature of the air.
All of this makes one worry for the Eskimos of Point Barrow, Alaska. Some years ago a Mexican restaurant (Pepe's North of the Border) opened in that mostly Eskimo community and was a big hit. The owner reported Eskimos couldn't get enough hot peppers, and some were even putting them into their soft drinks.
But becoming less sensitive to the temperature might be dangerous above the Arctic Circle. You think you've got it tough, croaking and gasping and fanning your mouth. Count your blessings--you could be wandering around on an ice floe in an endorphin high, heedless of imminent freezing.
So think about that. No more whining. Or gasping, if you can help it.