Anyone who has ever accidentally bitten into a piece of peppercorn knows: black pepper can be SPICY! But black pepper, botanically speaking, is a dried berry, and not related to chili peppers, the main type of plant that has capsaicin.
So does black pepper have capsaicin, and if not, then what makes it spicy?
Black pepper does not contain capsaicin
Capsaicin isn’t what makes black pepper spicy. Capsaicin is the compound found in peppers and a rare few other plants, but it is not found in pepper.
This also means that while pepper can definitely taste spicy it has a Scoville rating (SHU) of zero, because the Scoville scale specifically measures the concentration of capsaicin in any given substance.
What makes black pepper spicy?
So, if it’s not made spicy by the most common spicy substance, then why is black pepper spicy? Instead, pepper contains a different bioactive spicy compound called piperine. Piperine is closely related to capsaicin, both being a member of the vanilloid family.
As you know, when you bite into a peppercorn there is an instant, concentrated burst of spiciness, whereas when you eat a chili pepper the burn comes on more slowly, sometimes building over time as you eat more and more.
This is the same substance that makes other types of peppercorns spicy, so pink pepper and white pepper are also made spicy by piperine.
What does piperine do to your tongue?
We know that capsaicin binds to pain receptors in your mouth, causing pain that we describe as “burning”. Similarly, piperine is an irritant that is thought to bind to ‘vanilloid’ receptors in your mouth, causing an explosive spicy sensation.
While you can build up a tolerance to the spiciness caused by capsaicin, the evidence is mixed as to whether or not your tongue will become desensitized to the spiciness of black pepper. One study showed that irritation from piperine increased when applied a second time rather than decreasing, while a different study showed that the irritation decreased after a second application. The study also showed that piperine can cross-desensitize your tongue to reduce the effect of other irritant substances like capsaicin and nicotine.