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 is 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. Source: