Authentic Mexican food commonly uses ancho chilli powder for distinctive flavour. A substitute could make or break your dinner. Jean Andrews, deemed The Pepper Lady because of her years of investigation and international expertise on peppers, suggests acceptable substitutes.
The ancho chilli is the dried form of the poblano pepper. It falls into the mild to warm heat category ranging from 1,000 to 2,000 Scoville Heat Units. Pure capsaicin, the heat causing chemical in a chilli pepper, measures 16,000 SHU, and a red bell pepper measures zero SHU.
The poblano pepper and its derivatives taste sweet, like a bell pepper, but with a spicy bite. Originally from Mexico, related varieties of this pepper have been developed in the United States.
In her pepper guide, "The Pepper Lady´s Pocket Pepper Primer," Andrews suggests the Anaheim or New Mexico peppers as substitutes to the poblano.