The so-called capsaicinoids are responsible for the spiciness of chilies. The main component, the alkaloid capsaicin, is itself colorless and tasteless. It is extremely stable and is not destroyed by heating or freezing. Capsaicin is a white powder that is soluble in alcohol and fat but not in water. Therefore, it is not advisable to drink water after consuming spicy chili dishes.

The chemical structure of capsaicin:

C18H27NO3

The “burning” sensation upon contact with capsaicin is caused by the stimulation of nerve endings that are usually responsible for perceiving heat. This also explains why very spicy food appears to never or only slowly cool down. The spiciness of chili serves a biological function. Capsaicin, the main capsaicinoid in chilies, is produced by the plants as a natural defense against predators. It serves to deter animals from eating the fruits and endangering seed dispersal. The “burning” or spiciness that we experience when consuming chilies is thus an evolutionary adaptation to ensure the plant’s survival.

The capsaicin content and therefore the spiciness of different pepper varieties vary greatly. Even the same chili variety can vary in spiciness depending on location, climate, nutrients, and stress factors. Under stress conditions, such as insufficient or excessive irrigation, the plant reacts by producing increased amounts of capsaicin. This can also be used to increase the spiciness of chilies in specific regions. Additionally, temperature also affects the spiciness of chilies. Chilies that ripen at higher temperatures are generally spicier. The spiciness decreases from the base to the tip of the chili.

Spiciness is measured in Scoville units. The Scoville scale ranges from nearly zero for bell peppers to 350,000 for Habaneros. Some specially bred varieties exceed this value. The Habanero specialty breed “Red Savina” has been measured at up to 575,000 units (although this value has not been reproduced). Pure capsaicin corresponds to approximately 15 million Scoville units.

The spiciness of chilies can provide both enjoyment and challenge. Many people love the kick and the exciting taste experience associated with consuming spicy chilies. In many kitchens around the world, chilies are an essential component of traditional dishes, giving them their characteristic flavor.

It is important to note that sensitivity to spiciness can vary individually. Some people have a higher tolerance for capsaicin and can enjoy spicier chilies, while others may be more sensitive and prefer milder varieties.

If you want to know how spicy a particular chili variety is, you can check this scoville scale.