What is chili rating unit?

Chili rating unit (also known as Scoville scale) is a measurement scale used to determine the spiciness or pungency level of chili peppers and other spicy food items. It was developed in 1912 by Wilbur L. Scoville, an American pharmacist. The scale measures the amount of capsaicin, a chemical compound responsible for the heat sensation in chilies, in a given food item. The measurement unit is called Scoville Heat Units (SHU), which ranges from 0 (mild) to over 2 million (extremely hot). A pepper's rating on the Scoville scale is determined by how much it needs to be diluted with sugar water or other diluting agents until its spiciness is no longer detectable. Some common examples of peppers and their Scoville ratings include bell pepper (0 SHU), jalapeño pepper (2,500-8,000 SHU), habanero pepper (100,000-350,000 SHU), and Carolina Reaper (2.2 million SHU), the world's hottest pepper.