Things Scoville
How do you measure how hot something is? The terms "spicy" and "mild" are truly subject to opinion, as varied as each person's individual palates. So how can you categorize the heat of a certain pepper or sauce? You can't necessarily determine what you will think of a sauce based on someone else's opinion, because their own opinion is subjective.
A chemist named Wilbur Scoville pondered the same question, and in 1912 he developed a test to determine the heat of a pepper: the Scoville Organoleptic Test. The unit of measure for the heat of chile peppers is called the Scoville Heat Unit, and it is this unit of measure that is still used to this day. He originally tested peppers by diluting ground pepper in sugar water with a panel of tasters. He continued to dilute the ground pepper with more sugar water - drop by drop - until the pepper was no longer detectable. The amount of sugar water necessary to completely dilute the ground pepper indicated the heat level of the pepper, and he used that water measurement to calculate the Scoville Heat Unit.
Scoville Heat Units range from 0 (no heat) up to 16 million, which is pure capsiacin. Capsiacin is the stuff that makes the pepper hot - it's a crystaline alkaloid that is made by the pepper and is concentrated in the white, veiny "ribs" of the pepper. The higher the concentration of capsiacin, the hotter the pepper. The mildest of all are bell peppers, which contain no capsaicin at all and therefore have a Scoville rating of zero. The hottest pepper on Earth, according to the Guinness Book of World Records, is the Red Savina Habanero, which comes in at a whopping 577,000 Scoville Units. Pure capsaicin represents the extreme end of the scale, at 16 million Scoville Units. Pure capsaicin comes in a crystalized form, and is so hot that a single crystal in your palm will cause your skin to blister, actually burned by the capsaicin.
Within any species, Scoville ratings (capsiacin levels) can vary from pepper to pepper, depending on several factors, such as soil, climate and seed lineage. Also, the Scoville Organoleptic Test outcomes can be imprecise because it relies on subjective human testers. Most Scoville ratings are now determined by the "Gillett Method", another name for high performance liquid chromatography, which directly measures the level of capsaicin and has increased the level of accurateness of Scoville ratings 38%.
How do you cool your mouth after an encounter with capsaicin? despite what people say, drinking water is a bad idea. Because capsaicin is oil-based, it isn't soluable in water - the water will simply stir it around in your mouth. Instead, you should eat something that will absorb and carry away the capsaicin, such as milk, yogurt, bread, ice cream or juice.