Powdered cayenne pepper and chili powder may look similar, but they taste very different. While both of these spices contain capsaicin, the substance in hot peppers that makes your mouth burn, cayenne pepper usually packs a bigger punch. It also lacks the extra ingredients that you'll find in most blended chili powder preparations. You can substitute one for the other in some recipes, but you might need to adjust your other ingredients to account for the change in flavor.
How Hot Is It?
Food scientists classify cayenne as a medium-hot variety of pepper. This spice clocks in at between 30,000 and 50,000 units on the Scoville scale, a method of measuring the amount of capsaicin in a hot pepper. A thicker and milder variant of the traditional cayenne pepper rates only 2,500 to 5,000 Scoville units, but most spice manufacturers use the hotter version. The spiciness of chili powder blends varies according to the manufacturer. According to The Nibble, however, most chili powders come in at between 500 and 1,000 Scoville units. That's enough to produce a mild burn, but not enough to make really spicy foods.
The Beauty of a Blend
As its name implies, chili powder works well for making meaty, beany chili. This convenience mix includes ground chile peppers and spices like cumin, garlic powder, oregano and salt. You can add it to your chili or other recipes without worrying about how to balance the spices. This mix also allows you to keep just one jar on hand. If you use it in recipes that call for cayenne pepper, however, it could add extra flavors you weren't counting on.
A Chili by Any Other Name
While most “chili powder” sold in US grocery stores contains blended spices, this term can also be used for powdered hot peppers on their own. This usage is common in Asian recipes and grocery stores. These powders tend to be much spicier than blended American chili powder. If you are using a recipe that calls for powdered chili peppers of this kind, you can usually substitute cayenne pepper without significantly changing the taste of the dish.
When You Can't Get the Real Thing
Sometimes the spices you need aren't readily available. Whether you don't have access to a store that carries the right selection or you've run out temporarily, there are substitutions available for both chili powder and cayenne pepper. If you are making an American recipe that calls for blended chili powder, make your own by combining two parts ground hot pepper with one part ground cumin and one part ground oregano. If you don't have cayenne pepper, try using hot paprika or red pepper flakes instead.