The Scoville scale measures just how hot you can expect a pepper to be. That said, even with milder peppers like jalapenos, some batches can be spicier than the others. The age of the pepper, the climate, and the soil can all influence spiciness. A pepper’s heat is measured by units on the Scoville scale, and peppers over a certain Scoville level can make humans sick.
Capsaicin is the spicy chemical that triggers a rush of stress hormones. These will make the skin redden and sweat. It can also make someone feel jittery or energized. Some people enjoy this feeling. But there is another reason why chilies show up on dinner plates the world over. Hot peppers actually make food safer to eat.
When food sits out in warm weather, microbes on the food start to multiply. If people eat food with too many of these germs, they risk getting very sick. The cold temperature inside a refrigerator stops most microbes from growing. That’s why most people today rely on refrigerators to keep their food fresh. But long ago, those appliances weren’t available. Chilies were. Their capsaicin and other chemicals, it turns out, can slow or stop microbial growth. (Garlic, onion and many other cooking spices can, too.)
Various cultural cuisines are known for their peppers, whether it’s cayenne pepper in Cajun food, the Scotch bonnet in Jamaican jerk dishes, jalapenos in Mexican recipes, or peri peri peppers in Thai and Portuguese foods.
It’s not a 100% rule, but often the smaller the pepper, the more powerful heat it can pack. Think of those tiny red peppers tossed in Thai fried rice. So pretty and seemingly so benign because of their diminutive size, but eat one whole and brace yourself for a good sweat.
If you should run across a pepper that packs more punch than you can stand, contrary to your instinct, don’t drink water! Any liquid will simply swish the spicy oils around your mouth, keeping the fire lit and spreading it. Instead take a bite of bread or other starchy food like rice or tortilla and allow it to soak up the heat.