(CNN) -- Some like it hot - October is National Chili Month!
This hearty, slow-cooked stew will warm you from the inside out. While the inclusion of certain ingredients like beans and tomatoes will cause a hot debate among people from different regions of the country, almost everyone can agree: Chili just isn't chili unless it has chili peppers.
One of the world's first cultivated crops, the chili pepper's origin can be traced back to South America. According to food magazine The Nibble, Christopher Columbus was the first European to "discover" chilies. He called them pimientos, the Spanish word for pepper, because the spiciness reminded him of peppercorns. The two plants, however, are not related.
Chilies are high in vitamin C. Some of them are also high in the chemical capsaicin, which gives them their heat. Capsaicin is both the active ingredient in pepper spray, as well as topical arthritis treatments.
Chilies are classified according to their heat (i.e. the amount of capsaicin they contain). The first man to determine how to test for a chili's pungency (or heat) was Wilbur Scoville. The test was fairly simple: People were asked to taste a chili and then determine how many parts of sugar water it took to neutralize its heat. Today, a process determines how much capsaicin is in each chili in parts per million.
Here's the scale we use today:
Mild Heat: 0 to 5,000 SHUs
Medium Heat: 5,000 to 20,000 SHUs
Hot Heat: 20,000 to 70,000 SHUs
Extreme Heat: 70,000 to 300,000 SHUs
*SHU stands for Scoville Heat Units. On this scale, 0 is mild.
To put things in perspective, a serrano chili has up to 30,000 SHUs; a habanero up to 500,000; the bhut jolokia has 1,001,304 SHUs; and pepper spray has 2,000,000 SHUs.
The most common method people use to neutralize the burn of a chili is drinking milk. This is because capsaicin doesn't dissolve in water, but it does in fats. So, alcohol will also serve the same purpose.
As for cooking with chilies, the capsaicin is found mostly in the seeds and the membrane that holds the seeds to the inside of the peppers. Removing both the seeds and the membrane will decrease a chili's SHUs. For safety's sake, always wash your hands and cutting board after chopping up a chili, and don't rub your eyes, nose or mouth. For chilies with more SHUs, consider wearing gloves as you cook.
There are hundreds of varieties of chilies, and endless ways to use them in cooking. If you're just starting out in your experimentation with heat, try red pepper flakes then move up to jalapeños and serranos. You'll build up a tolerance as you go. For those more accustomed to cooking with chilies, try using them in unexpected ways, like dessert. Chilies go great with chocolate and sweet fruits like pineapple.