How hot are those chili peppers?
If you like to cook with chili peppers--and so many people do these days, given the popularity of such spicy cuisines as Mexican, Asian, and Caribbean--you've probably heard of the Scoville scale. Chili aficionados will brag that their favorite chilies are the hottest, with a scorching 300,000 on the Scoville scale, while that jalapeño you've just learned to love only measures a wimpy 4,000. But what exactly do these numbers mean, and how do they translate into useful information?
The Scoville Scale
Scoville took the guesswork out of judging chilies. Let's start with the invention of the Scoville scale, and then we'll look at how different varieties of chiles rank in this heat hierarchy. In 1912, a man named Wilbur L. Scoville was working for a company that made an ointment for aching joints in which capsaicin, the heat-causing compound in chilies, was an important ingredient. The company was constantly frustrated because the heat level in chilis varied so much. Scoville devised a formal test in which exact weights of chilies were dissolved in alcohol and then added to sweetened water in precise measures. Tasters were asked to determine how much water was needed to neutralize the heat. A rating number was assigned, according to how many units of water were added before the chili's heat became imperceptible.
Scoville's test was used for the next six decades, yet it wasn't totally reliable, given the fact that human testers' palates are different and easily fatigued by repeated tastings of hot food. In 1980, a more objective test was introduced, the High-Pressure Liquid Chromatography Test, in which powdered chilies are dissolved and then analyzed through a light beam that shows the heat compounds as fluorescent. Most large producers use this test today, but because the Scoville name has been so deeply ingrained in the industry, they make a conversion and still express the pungency in Scoville units.
The Scoville scale ranks fire but not flavor. So what does any of this have to do with the flavor of chilies? Not much. These tests isolate only the heat-causing compounds, but tell us nothing about the overall flavor. The heat of a chili is found in the inner membrane, while the flavor comes from the meaty pod itself and makes all the difference in how we experience the heat. These tests also do nothing to discern how the heat is felt. As anyone who has eaten a lot of chilies will tell you, some, such as the habanero, deliver sharp, quick bursts of heat, while others, such as the fiery red Thai pepper, burn and linger. Some hit you up front on the lips and tip of the tongue, while others scorch your entire mouth and throat. Even the researchers themselves will admit that for all their accuracy, the pepper is a fickle plant: its heat varies widely from pod to pod, plant to plant, garden to garden, and season to season. Even on a single bush, a pod from the sunnier side will be hotter than one from the shady side. A quick look at a sample Scoville scale (right) shows the wide variances within each type of chili.
The Scoville rating provides a good general measure of the relative heat of different chilies. In other words, you can be assured that a cayenne will be hotter than a poblano. But ultimately, taste remains a subjective experience. There’s no substitute for breaking open a chili and tasting it yourself (carefully) for flavor and, of course, for firepower.
The Right Techniques for Fresh Chilies
Fresh chilies are becoming more available all the time, and few supermarkets are without the ubiquitous jalapeño. But the range in quality can be discouraging, and it can be difficult to distinguish fresh chilies from ones that have been on the shelves a while. When shopping for fresh chilies, look for those with smooth, tight skin and a thick, meaty body. A fresh chili should have some heft relative to its diminutive size.
If you won’t use your chilies right away, keep them cool and dry. You can refrigerate them, but be sure to first remove them from the plastic produce bag; otherwise, they’ll be-come soft and moldy. The length of time that chilies will stay fresh in the refrigerator depends on how fresh they were when you bought them, but generally they’ll keep for three or four days without suffering any loss of freshness. Once the chilies skin begins to wrinkle, it will lose some of its potency, and if you’re roasting or blanching them, the skins will be difficult to peel.
THINK ABOUT SAFETY
Unless you have particularly tough hands, it’s a good idea to use rubber gloves when handling fresh chilies. Many cookbooks recommend using dish washing gloves, but I find that these are rather clumsy and that getting a handle on small chilies while wearing them can be frustrating. Instead, I like to keep a few pairs of surgical gloves around the kitchen. Available at most drugstores, surgical gloves are cheap, disposable, and best of all, they allow you to get a firm grip on the chiles. Once you’ve begun working with the chilies, be extremely careful not to touch any part of your body, especially your eyes. After you’ve finished, wash your knife and cutting board with hot soapy water.
Protection with a grip. Surgical gloves protect sensitive skin from chili’s painful sting, and they improve your grip.
Capsaicin is the chemical compound that gives chilies their heat. An alkaloid, capsaicin is distributed throughout the chile, but the heaviest concentration of capsaicin is found in the white pith on the inside of the chili–those ribs that hold the seeds in place. Further down on the scale of concentration are the seeds and then the chili’s flesh, which has the least amount of capsaicin. This gives you a convenient way of controlling the amount of heat that the chili contributes to a dish. To get the most bang out of the chile, use it whole; for a milder flavor, simply trim out the seeds and ribs.
CUTTING CHILI PEPPERS THE EASY WAY
Start by cutting off the entire stem, and then slice the chile in half lengthwise. With the tip of a paring knife, you can remove the seeds and ribs by slicing or nudging them with the knife point. With seeds and ribs out of the way, the chilies are easily cut into strips or a fine dice.
Stemming and seeding
a chili. After removing the stem, slice the chili lengthwise to expose the seeds and ribs. Remove the seeds and ribs to moderate the heat, or leave them in for extra punch.
REMOVING THE SKINS
Many dishes, especially Mexican and Southwestern recipes, call for the chiles to be peeled. You can do this by first charring or blanching the whole chilies. To char, rub them with a little oil and then set them directly over a gas burner. Turn the chilies frequently with tongs or a fork to prevent burning through to the flesh. When the skins have charred and blistered slightly, pop the chilies into a plastic bag and let them steam in their own juices for about 20 minutes. The skins should now rub off easily.
Blanching chilies won’t give you the smoky flavor that charring does, but the technique is great if you don’t have a gas stove. Simply drop the chilies into boiling water for 30 seconds or so, and then plunge them into ice water. Once the chiles have cooled, they can be skinned just as if they were charred.
Drying chili peppers
Drying chilies is one of the best ways to preserve your harvest, but be sure to dry them when they’re fully ripe for the finest flavor. For poblanos, this means when they turn bright red. Any type of chili can be dried by one of the following methods, except for jalapeños, which do best when they’re smoke-dried (turning them into chipotles). Don’t try drying chilies with black spots; they’ll turn moldy and rot.
If you live in a dry climate, the simplest way to dry the chilies is to tie them on a string by their stems, in clusters of three, and hang them in the sun. This is called a ristra. When the pods are dry but still pliable (this could take weeks, depending on the heat and humidity), hang them indoors and out of direct sunlight to finish drying.
In areas of high humidity, the chilies might rot before the sun can dry them, so your best bet is to halve them lengthwise and use the oven (or a food dehydrator). In a gas oven, set the halved chilies directly on a baking sheet and dry them using just the heat from the pilot light. This may take a couple of days or longer. In an electric oven, the chilies will dry much faster. Set the oven to low, about 175°F, and check the chilies every
few minutes to make sure they don’t burn.
The chilies are fully dry when they snap, not just bend. Store them in sealed glass jars in a cupboard, or in the freezer double-wrapped in freezer bags. (Don’t put bagged chilies in a cupboard because the plastic is porous and the chilies can oxidize, ruining both the color and the flavor.) With both storage methods, dried chilies last indefinitely.
To reconstitute the chilies, soak them in hot water for about 15 minutes, fry them in a bit of oil until they puff up, or lightly roast them. Dried chilies can also be ground to a powder when you’re ready to use them (no earlier, because the powder would lose its flavor).