I suspect that everyone who cooks on a regular basis for many years on end develops some favoritism in the spices and seasonings department. I certainly have. I'm extremely partial to garlic, fresh sage, cardamom, and ancho chili powder - though they rarely all make it into the same dish. I've been chipping away at the garlic gap for a few years now, and have seen harvest of ten pounds or more for the last couple of years. Fresh sage is only in season for about six months of the year, though preserving it as a compound butter does help extend the joy. Cardamom is entirely out of my hands, but ancho powder has been tantalizingly near since I started gardening seriously.
First, a definition. An ancho chili pepper is botanically one and the same as a poblano chili. It becomes an ancho chili when it is smoked and dried. Additionally, I'm pretty sure that the chili only classifies as an ancho after it has been allowed to ripen on the plant from its early green color to a deep red. Only then is it smoked and dried, and, at times, powdered for ease of use in the kitchen. Poblanos/anchos are quite mild as chili peppers go. They are noted more for their marvelously rich flavor than for powerful heat. This means you run no risk of dispersing mustard gas-like irritants into the air while drying them. However, you should still wear gloves when cutting them up. They pack enough of a punch to let you know about it should you get the oils on sensitive skin, or worse yet, eyes or mucus membranes.
My first attempt at making ancho chili powder came last year. It was an utter failure. I duly waited for the chilies to turn red, then smoked them whole and strung them up to finish drying in a cool dim room of the house. Big mistake. Though they looked fairly well on their way to drying when they came out of the smoker, there was still sufficient moisture inside to allow them to molder from the inside out. Compost. Our climate, at least last year, wasn't hot enough to allow chilies to dry down unaided inside the home.
This year I started with a different approach. I left the peppers whole, but cut several long slits in the sides before putting them in the smoker. This helped speed the drying somewhat, and also allowed for better penetration of the smoke. But it still took far too long to dry the peppers. And I found the seeds of the chili made for a rustically uneven texture after grinding. Scratch that approach. So for my second batch, I cut the peppers entirely open, removing most of the ribs and leaving only a small number of seeds intact to add what heat they might. This worked well. For smoking material, the apple wood chips from our own apple tree give a marvelous flavor. But other fruit or hardwood chips would probably work just as well. Can you imagine it? A patchwork quilt of homegrown chili powders across the land, each one imbued with distinctive terroir!
The smoked pepper slices needed about 24 hours of further drying in a dehydrator. This was accomplished over two days, with the dehydrator situated on the driveway. The Excalibur dehydrator has a temperature control, so I figure I save energy by placing the box where it's already pretty hot from the sun. The fan still needs to run of course, but I doubt much energy is required to nudge the temperature up to 125 F, which is about optimal for the peppers. When done drying the peppers should be just barely pliable. They lose about 85% of their weight through trimming and dehydrating.
From this state, some sources recommend "toasting" the dried chilies in a dry skillet, to crisp them up just a bit more before pulverizing. I omit this and simply put the freshly dried chilies into a food processor. This produces a coarse grind. After that, it's a question of my patience and free time. I have a spice grinder which can take the relatively coarse results from the food processor down to significantly finer powder. But if I want to be really finicky, I have to screen that powder through a very fine mesh and reprocess whatever doesn't pass through the screen. I've troubled myself to make only a very, very small quantity of this finely textured ancho chili powder. And I rarely cook anything in which the exact texture of a powdered spice is going to affect the outcome of the dish.
My homemade ancho has a much stronger aroma than any powder I've been able to purchase. It also has a tendency to clump a bit; so I wonder whether commercial products add an anti-caking agent, or whether they simply use a different processing technique. I use ancho powder in bean dishes, on quesadillas, and even to flavor the butter I drizzle over our homegrown popcorn. (I know you popcorn purists will cry, "Sacrilege!" But give it a fair shake at least once - that's all I'm saying.) Sometimes I'll even sneak it into futomaki in place of togarashi; ancho's flavor combines very well with toasted sesame oil. From a pound of whole poblano peppers I get about 1/3 cup of finished chili powder. I doubt we'll generate a year's supply from the three plants that have done well in this year's heat. I estimate we'd need double that number in a good year to keep us in ancho powder till the season rolls around again.