Chile de Árbol
Bright with smoky undertones, per America's Test Kitchen; Rick Bayless points to its natural earthiness.
15,000 to 30,000 SHU, per Fiery Foods (DeWitt). Log scale against the hottest chile in this guide.
The de árbol is a thin, bright red chile, an inch and a half to three inches long, and it is hot. The name means tree chile, for the bush it grows on.
Fiery Foods' glossary says the plant looks like a small tree, which gives the chile its name. It is grown mainly in Jalisco and Nayarit and goes by many local names, including pico de pájaro (bird's beak) and cola de rata (rat's tail). NMSU has released de árbol varieties with orange, red, and yellow pods.
Dave DeWitt notes that the pod has the same name fresh or dried, but it is sold almost only dried. Cooks toast the pods briefly, soak them, and blend them into salsas, or crumble them whole into a pot.
Rick Bayless builds a fiery table salsa from árbols and roasted garlic, adding a few guajillos to calm it down.