To make your own chili powder you really only need 4 ingredients: 1 Tablespoon Cumin seed, 3 Ancho chilies (dried poblano chilies), 3 dried Anaheim chilies (New Mexico chilies), and 3 dried cayenne peppers. The process for turning these simple ingredients into an amazing chili powder only has 3 steps.
First thing to do is to cut the tops off the peppers and try to shake out as many of the seeds as possible. try to get them all but leaving a few does not kill the final product. Cut the peppers up or if they are very dry just crumble them into a medium sized pan with the cumin seed.
Toast the chilies and cumin seed on medium high heat for several minutes. I know when mine is ready when either the chilies start to darken or I can smell them from across the room. It's a pretty hard to do this wrong, if you are worried about overcooking the mix just go ahead and move on to the next step. The entire purpose of this step is to waken up and release the oils that are still in the chilies and the cumin seed.
Finally put the mixture into a blender or coffee grinder and blend it up until it has turned into a nice powder. When using a coffee grinder you will not be able to put all of the mixture at at once so go ahead and do it in batches. When I use my blender I can just about fill it with the toasted chilies but once it has all turned to powder its about 1/4 cup. Which is enough for 2 or 3 different recipes.
Fresh is best, one of the great things about this recipe is that its really all I need for the few weeks that it keeps up its "freshness". This has been my secret ingredient for the past several years in chili cook-offs and absolutely takes my Texas style brisket to a whole new level.
That really all there is to it. Making your own chili powder at home is going to reward both you and your guests with better food and better times. Stop spending money on store bought chili powders that can seriously compare to what you can make for yourself. It is not difficult and the improved smell and taste of your dishes will make you wonder why on earth you would bother using a store bought chili powder.