to the brainstem and thalamus where heat and discomfort are perceived. However, birds are unable to perceive the hotness and so they can eat some of the hottest peppers. The intensity of the "heat" of chili peppers is commonly reported in Scoville heat units (SHU), invented by American pharmacist Wilbur Scoville in 1912. Historically, it was a measure of the dilution of an amount of chili extract added to sugar syrup before its heat becomes undetectable to a panel of tasters; the more it has to be diluted to be undetectable, the more powerful the variety, and therefore the higher the rating. The modern method is a quantitative analysis of SHU using high-performance liquid chromatography (HPLC) to directly measure the capsaicinoid content of a chili pepper variety. Pure capsaicin is a hydrophobic, colorless, odorless, and crystalline-to-waxy solid at room temperature, and measures 16,000,000 SHU. Capsaicin is produced by the plant as a defense against mammalian predators and microbes, in particular a fusarium fungus carried by hemipteran insects that attack certain species of chili peppers, according to one study. Peppers increased the quantity of capsaicin in proportion to the damage caused by fungal predation on the plant's seeds. Common peppers A wide range of intensity is found in commonly used peppers: Notable hot chili peppers The top 8 world's hottest chili peppers (by country) are: NOTE: SHU claims marked with an asterisk (*) have not been confirmed by Guinness World Records. Uses Culinary uses Chili pepper pods are technically berries. When used fresh, they are most often prepared and eaten like a vegetable. Whole pods can be dried and then crushed or ground into chili powder that is used as a spice or seasoning. Chilies can be dried to prolong their shelf life. Chili peppers can also be preserved by brining, immersing the pods in oil, or by pickling. 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