Some experts think that we like chillies because they’re good for us and we are following some biological imperative - not because we are indulging in a type of culinary sado-masochism. Some claim that hot peppers can help lower blood pressure and that they destroy some bacteria. All are agreed that chillies increase the production of saliva which may help if you also eat bland food like corn or rice.
So how hot is hot? The Scoville scale is used to measure the spicy heat of a chili pepper. The number of Scoville heat units (SHU) gives the amount of capsaicin present. Capsaicin is a chemical compound that stimulates or irritates the nerve endings in the skin, especially the mucous membranes. Although the presence of capsaicin can now be measured by a chemical test the Scoville scale - developed in 1912 – initially relied on the perception of individuals taking part in the tests. This was done by getting them to taste different mixtures containing varieties of chilli pepper combined with a neutral-tasting food.
On the standard Scoville heat scale capsicums (in America known as Bell peppers) register nil, the hottest Indian jolokia peppers register around 1,000,000. Orange habaneros - the name comes from Havana, Cuba and they are also called scotch bonnets because of their shape - range from 100,000 to 350,000. Jalapenos (originating in Mexico) can be mild or hot anywhere from 5,000 to 50,000.