The
serrano is pronounced: suh
rah noh.
Serrano chile peppers have thin walls. They don't need to be steamed or peeled before using, making it the easiest chile pepper to use for salsas. The serrano chile is green in color at first, and ripens to red, brown, orange, or yellow. Serrano chile peppers don't dry well, since they are too meaty. It is said to be about 5 times hotter than the jalapeño.
The serrano rates between 8,000 and 22,000 Scoville units on the heat index.