Chilli peppers are a small, fiery variety of capsicum. They can be green, yellow, orange, red or black. There are more than 200 known varieties and they differ greatly in size, colour and level of hotness. In general, the smaller the chilli, the more potent, but it's worth bearing in mind that individual chillies of the same variety and even from the same plant can contain different levels of capsaicin, the volatile oil that gives chilli its heat. There is an official heat scale for chillies known as The Scoville scale, developed by Wilbur Scoville in 1912. A sweet pepper scores 0 on the scale, Jalapeño and chipotle chillies score anything between 2,500 to 10,000 and habañero and Scotch bonnet score 80,000 to 300,000 plus! Chillies work well in sweet as well as savoury dishes: a little chilli helps to cut through the richness of the chocolate..
Chili pepper pods, which are berries, are used fresh or dried. Chilies are dried to preserve them for long periods of time, which may also be done by pickling.
Dried chilies are often ground into powders, although many Mexican dishes including variations on chiles rellenos use the entire chili. Dried whole chilies may be reconstituted before grinding to a paste. The chipotle is the smoked, dried, ripe jalapeño.
Many fresh chilies such as poblano have a tough outer skin that does not break down on cooking. Chilies are sometimes used whole or in large slices, by roasting, or other means of blistering or charring the skin, so as not to entirely cook the flesh beneath. When cooled, the skins will usually slip off easily.
The leaves of every species of Capsicum are edible. Though almost all other Solanaceous crops have toxins in their leaves, chili peppers do not. The leaves, which are mildly bitter and nowhere near as hot as the fruit, are cooked as greens in Filipino cuisine, where they are called dahon ng sili (literally "chili leaves"). They are used in the chicken soup tinola. In Korean cuisine, the leaves may be used in kimchi. In Japanese cuisine, the leaves are cooked as greens, and also cooked in tsukudani style for preservation.
Chili is by far the most important fruit in Bhutan. Local markets are never without chilies in different colors and sizes, in fresh and dried form. Bhutanese call this crop ema (in Dzongkha) or solo (in Sharchop). Chili is a staple fruit in Bhutan; the ema datsi recipe is entirely made of chili mixed with local cheese. Chili is also an important ingredient in almost all curries and food recipes in the country.
In India, most households always keep a stack of fresh hot green chilies at hand, and use them to flavor most curries and dry dishes. It is typically lightly fried with oil in the initial stages of preparation of the dish. Some states in India, such as Rajasthan, make entire dishes only by using spices and chilies.