Whether you’re a certified chilehead or more of a chile-phobe, adding hot peppers to a dish can seem a bit chancy: Maybe they’ll add a gentle tingle, or maybe they’ll set your mouth on fire. Uncertainty is always part of the game when working with chiles, but controlling (or unleashing) the burn is a little easier when you understand the anatomy and chemistry of this fiery fruit.
Chile lovers are made, not born
The “hot” in hot chiles comes from a chemical commonly known as capsaicin. But capsaicin isn’t the sole culprit behind chiles’ heat. The fruits actually produce about 14 pungent compounds, called capsaicinoids. The exact blend of capsaicinoids differs from one type of chile to another, which is why different chile varieties burn in different ways. For example, habaneros seem to spontaneously combust in your mouth, and jalapeños slowly smolder.
When you bite into a dish containing chiles, capsaicin triggers a burst of a chemical (called substance P, as in pain) that sends pain messages to your brain. If you eat a lot of chiles, these pain messages will subside, your tolerance will rise, and you’ll be able to enjoy hotter and hotter food. That’s how chileheads are made.
But chile tolerance isn’t permanent. If you stop eating chiles for a while, you’ll have to suffer the burn all over again. Don’t worry, though, there are remedies to get through it.
Milk, not water, eases the pain
When your mouth is on fire from overdosing on chiles, your first instinct may be to reach for water. But resist: Water won’t relieve the agony; it will just spread the capsaicin compounds—and the pain—around in your mouth. In 1989, John Riley, editor of the journal Solanaceae, found that milk is more effective at relieving the sting. It appears that casein, a protein in milk, acts as a detergent and strips capsaicin from the nerves sending those pain messages. In fact, any product that contains casein can bring relief: sour cream, yogurt, even ice cream. Another study done one year later found that room-temperature sugar water was as effective as cold milk. This may explain why some cooks say that sugar can reduce the heat in a dish that is excessively hot.
Where the heat is
Seeds don’t make chiles hot—the fire comes from tiny capsaicin glands between the pod wall and the white spongy ribs. When you cut a chile, you rupture these glands, and capsaicin spills out onto the seeds, which is why they seem to contain the heat. To minimize the release of capsaicin, make one cut through the chile, rake out the ribs and seeds, and rinse the chile well.
Adding heat is easier than removing it
When it comes to cooking with chiles, chile experts say that capsaicin is very stable—heat doesn’t destroy it, freezing doesn’t wipe it out, even acids don’t seem to neutralize it (although acids do have some effect; the vinegar in Tabasco sauce, for instance, helps preserve its heat). “The main things that determine the heat of a dish are the pungency of the chile and the amount of chile you use,” says Dave DeWitt, who has written more than 30 books on chiles. So if you’re trying to minimize chiles’ heat, a good place to start is to choose a variety with a heat level on the lower end of the scale (see the sidebar at right) and then proceed with caution, starting with a small amount and tasting as you go. “You have to look at heat like you look at salt,” says Dr. Paul Bosland, director of the Chile Pepper Institute. “Too much salt can ruin a dish. So can too much heat.”
How hot is hot?
When chile connoisseurs talk about the heat levels of chiles, they toss around really big numbers. These are Scoville heat units (SHU), and they describe pungency on a scale from 0 to over 500,000 units. In the supermarket, you might see chiles ranked on a simpler 0 to 10 scale. Keep in mind that many factors, from genetics to growing conditions, will affect the heat of an individual chile. That’s why the jalapeño you bought yesterday might be a lot tamer than the one you get today.