How Chili Peppers Work

The heat in chili peppers is called pungency, and it comes from a group of compounds called capsaicinoids. Capsaicin is the primary heat-producing alkaloid present in peppers. The greater the concentration of capsaicin, the hotter the pepper tastes. The amount of capsaicin in a pepper also varies according to hereditary and environmental factors.

It's often said that seeds are the source of the heat in chili peppers, but while the seeds are hot, they don't cause the heat. The membrane, called the placenta, stores the heat -- the seeds are attached to the membrane, but the heat is transferred to the seeds, not stored in them.

The mouth's pain receptors -- not the taste buds -- transmit the heat sensation with the help of a neurotransmitter called substance P [source: University of Illinois]. A runny nose and watery eyes often follow the immediate wave of fire, and some people perspire profusely. Capsaicin also releases endorphins in the body, causing some people to feel exhilarated -- the same way that endorphins causes a runner's high. There's also an added bonus to enjoying an occasional fiery pepper: The capsaicin triggers thermogenesis, a fat-burning process.

Another myth is that chili peppers can cause ulcers, but evidence suggests that capsaicin can actually protect the stomach lining [source: Mateljan]. However, anyone taking anticoagulants, such as coumadin, should avoid large quantities of hot peppers because they may thin the blood [source: Graedon and Graedon].

If you've ever swallowed a searing chili pepper, you know that you instinctively want to down a jug of ice water to douse the flames. Not so fast! The heat-inducing compounds in peppers are fat soluble, so reaching for that glass of water is like throwing water on a grease fire -- it reignites the flames. To counteract the heat, reach for bread, chocolate, milk or other dairy products. Mexican dishes often include a side of sour cream, and Indian dishes are frequently served with a side of yogurt to tame the heat.

You may be wondering how to determine the relative pungency of different peppers. Keep reading to learn about the three basic methods for measuring heat.

The relative pungency of chili peppers is reported in Scoville Heat Units. SHU range from zero, the mild end of the scale, to more than 16,000,000 units, for pure capsaicin [source: Netha and Reddy]. To put this into perspective, the bell pepper rates a zero, and the world's hottest pepper, the Bhut Jolokia, rates 1,001,304 SHU [source: Bosland and Baral].

Historically, there have been three methods used to determine the relative heat of peppers. The first involves a simple taste test. Obviously, the results of this type of test are questionable, but the feedback is immediate. However, two formal tests have been devised and used throughout the 20th and 21st centuries [source: The Chile Pepper Institute].

Wilbur Scoville developed the Scoville Organoleptic Test in 1912, and it uses human subjects to report a pepper's heat in terms of SHU. Each test subject tastes repeated and greater dilutions of a pepper extract until the heat is no longer detected. The Scoville test was the standard until recently, but it received ridicule for its subjectivity and lack of accuracy. While the test is no longer the standard, the SHU remains the standard measure of pungency [sources: Tabasco.org, The Chili Pepper Institute]

The high-performance liquid chromatography test was introduced during the 1970s and is the industry standard for measuring pepper pungency [source: University of Kentucky]. Chili peppers are dried and ground, capsaicin is extracted from the powder, and then the extract is run through the HPLCmachine, which analyzes and reports the powder's heat level [source: The Chile Pepper Institute]

Next, we'll look at a variety of common peppers that run the gamut from tame to red-hot.

All chili peppers are edible, but the devil lies in the details and in your definition of edible. Science classifies chili peppers by heat and shape, and aficionados add color to those classifications [source: Texas A&M University]. Shapes range from short and squatty to long, thin and tapered. Colors include shades of red, green, yellow, orange, purple, brown and black.

Small, thin peppers generally contain the most fire -- exceptions include the banana pepper. Red varieties are typically hotter than green, but some notable exceptions include mild cherry and pimento varieties. Ripe peppers contain more heat than underripe peppers of the same variety.

Versatility distinguishes mild chili peppers from their fiery cousins, and mild peppers can be served raw, pickled or roasted, or they can be added as an aromatic to savory dishes. Common mild peppers include:

Hot chili peppers are used primarily as a condiment, and common types include:

A dried pepper contains more heat than its fresh equivalent because the lack of moisture concentrates the flavors. If you substitute dry peppers for fresh ones, be sure to adjust portions according to taste.

The most common powdered peppers are cayenne and paprika -- cayenne adds heat while paprika adds seasoning to dishes. When used sparingly as a garnish, paprika adds color without affecting taste.

Next, we'll reveal the best ways to select, store and prepare chili peppers.

When selecting chili peppers, choose ones with bright, vivid colors and firm skin. Avoid any with wrinkled, soft or bruised areas.

You can safely eat chili peppers before they're fully ripe -- the longer they ripen, the hotter they get. Buying red peppers that still exhibit some green coloring indicates that they're not fully ripe, but peppers ripen even after leaving the vine. Chili peppers have a long shelf life, and you can store unwashed ripe peppers in the refrigerator for several weeks.

The hottest chili peppers can be topically toxic, so remove contact lenses, and wear protective eyewear and thin vinyl gloves when working with hot chili peppers. Avoid touching your face, eyes and nose while working, and wash your hands immediately after touching the peppers.

To reduce the heat level of any pepper, remove the membranes and seeds before slicing or dicing the pepper. To remove seeds and membranes while keeping the pepper intact, carefully cut and remove the top of the pepper. When separating the top from the body of the pepper, try to remove as many seeds as possible. Scrape the inside of the pepper with a spoon to remove the rest of the seeds and the membrane.

Nothing compares to the first taste of a silky, smoky roasted pepper. To roast peppers, place them on a baking sheet in an oven heated to 375 degrees Fahrenheit (190 degrees Celsius). Check the peppers every 15 to 20 minutes, and turn them when the top has charred and blistered. Repeat until all sides are charred. Place the peppers in a brown paper bag and close it to allow the steam to loosen the skin. . After 15 minutes, remove the peppers from the bag, peel away the blistered skin and enjoy.

You can preserve peppers by canning or drying them, but the simplest method is to freeze them. Place fresh slices in a single layer on a baking sheet, and place the baking sheet in the freezer until the peppers are frozen. Pack frozen peppers in a zipper-seal bag or vacuum seal and freeze them for up to a year.

Have you ever considered growing your own chili peppers? If so, keep reading to get some gardening tips.

India is the world's largest chili pepper producer [source: Mikulak], which should come as no surprise if you like Indian food. New Mexico is the largest domestic grower -- again no surprise, as Southwest cuisine incorporates the pepper into everything from breakfast dishes to desserts [source: Huntrods]. Today, you'll find domesticated chili peppers growing in almost every country in the world.

Chili peppers belong to the nightshade (Solanaceae) family along with potatoes, tomatoes, goji berries and eggplants. Peppers belong to the Capsicum genus, and the five domesticated species include: Capsicum annuum, Capsicum chinense, Capsicum frutescens, Capsicum baccatum and Capsicum pubescens [source: The Chile Pepper Institute]. All are tender perennials, but they're grown as annuals in colder climates. They grow on small shrub-like plants, and they're self-pollinating.

Chili peppers are easy to grow in a backyard garden or in containers as long as you can control the moisture. Chilies prefer a well-drained soil rich in organic matter -- adding compost to the soil before planting will aid in water retention and drainage. Chili peppers are picky germinators, so soak seeds in water for a day or two before planting, and set them with a starter solution to aid germination. Keep them in the warmest part of the house until they germinate.

The plants will produce higher yields when they're planted indoors and then transplanted after any chance of frost has passed -- it's best to plant chili peppers in trays approximately 10 weeks before your last frost date. Before transplanting, harden off the tender plants to acclimate them to their new environment. To harden them off, move plants outdoors each day for a week or two. At first, leave them outdoors only for a few hours in the morning, and then gradually work up to the entire day.

Fertilize the plants after the first few flowers have appeared if they look lanky or yellow. Pull weeds by hand, but be careful not to disturb any roots, and ensure the plants receive two inches of water per week throughout the growing season. When peppers are firm, harvest them by cutting the stem and leaving a little of the stem in place -- longer stems increase the pepper's shelf life [source: extension.org].

Now that you're growing your own peppers, you can use them to spice up a variety of different dishes, but enhancing cuisine isn't their only use. Did you know that chili peppers have many nonculinary uses? Keep reading to learn more.

Chili peppers are bursting with free-radical scouring antioxidants, and studies show that capsaicin exhibits antiviral and antibacterial properties as well [source: Plant Cultures]. Proven topical applications of chili peppers include creams, gels, lotions and patches to relieve joint and nerve pain often associated with osteoarthritis and diabetic neuropathy. In the future, capsaicin injections may replace cortisone injections [Carter, Lazar and Burch].

While capsaicin irritates, it may also have homeopathic qualities. In fact, scientists believe that capsaicin may be able deplete substance P, the neurotransmitter that alerts the central nervous system to pain [source: Block and Beale].

Capsaicin has several other medical uses, including:

Ongoing studies show promise in the prevention and control of an array of conditions, including:

Two common commercial uses of chili pepper derivatives are pepper spray and food and cosmetic dyes developed from oleoresin [source: The Chile Pepper Institute]. But Chinese police also serve them to sleepy motorists to keep them awake at the wheel, and at one time, chili peppers were used to stop advancing soldiers [source: Reuters].

Cayenne powder also has several different uses. Gardeners use it to deter mammals and insects, and homeowners use it to repel ants, squirrels and other wildlife. Some people even add a dash of cayenne powder to their socks to keep their feet warm [source: The World Bank].