Wrap that blender in a towel or bag if you use a blender like mine. You will make pepper spray basically if you run it to long and it turns to dust. I recommend giving it a minute before you pull the top off the blender.
I agree with @clarkinks as far as the precautions are concerned, unless you want to purge your sinuses and tear ducts.
It sounds like you have quite a few. For the best flavor, I would only do as much as you might use, say, for the next 3 months. All peppers seem to loose some of their flavor characteristics with time after being ground.
I used a little Krups coffee grinder for my dried hot peppers. It contained the dust very well but I had to pull a t-shirt over my face to avoid the fumes when emptying the device; a small brush was handy. I still have some powders in amber bottles, kept frozen, dated 1999 and 2001; it does not cake and remains potent.
For non-blender grinders I’ve found Epica to make the best engineered, adequately powered, low priced model. Here you can see it compared to the Krups. Note the stainless steel cup that lifts from the grinder so you can easily dump the contents. It has good power as well. Grinds coffee very quickly also and the blades hold their edge well- must be very hard steel.
I grind chili powder fresh pretty regularly because it loses quality pretty fast once ground. I like the coffee grinders. I keep several around for different uses so I don’t have to clean them all the time. Once for sweet spices, one for chili powder, one for coffee of course I actually did a little chili powder video this year talking about all that. Nothing mind blowing, but it’s pretty. https://youtu.be/7XzR772qA1g I go for the cheap grinders at thrift stores and yard sales. They break eventually, but there are a lot of them out there.
I use a coffee grinder. I sort of disagree or I guess have my own methods. I find powders last quite awhile if made fresh. Even so I grind as needed in most cases. I store chile’s whole dried.
Here’s how I make my Chili or chile powder. I use new Mexico chiles
Big Jim, 6-4, or Joe E Parker are good choices for chile’s. I use most in the green stage for other things, I grow at least 6 plants every year. I grew 8 this year. I need a lot of green and a lot of red ones this year.
So I use 3 chile peppers.
4 ancho peppers. (still experimenting with various poblanos)
For heat I might add dried hot peppers, cayenne is traditional, but any can be used. Use 3-5 depending how hot you like it. Or skip it for a mild form. Some New Mex chile’s can be hot all by themselves. Such as Sandia.
2 tbsp of cumin seeds dry roasted
2 tbsp of fresh ground garlic powder (I dry my home grown)
2 tsp of Mexican oregano or regular is OK, but the Mexican is amazing. I grow my own.
Grind and mix it all and you have real chile powder! The stuff is amazing. I always look forward to it this time of year as I have all the ingredients fresh. One day I may try growing cumin too! The only store bought essential ingredient.
I dry my peppers whole, well not really. Room is always an issue so I dry them cut in half with seeds removed. I add a drying agent too, I got a bunch from nicorrete lozenges my best friend uses. He saves them for me.
When using I finish drying in the oven if needed. I try not to dry them out completely in this first drying.
I don’t have any finished product yet. I’m out and still drying anchos and chile peppers. I have about 50 still on the plants. Most dishes I use this on I make in the winter months.
I’m still making dishes that require fresh herbs and such. Plus I’m busy as all heck with fall harvests! I still have peaches on one tree!
You can, But I do as John mentioned. Seeds make them hotter, if you want that. With some I do! When using green chiles for various dishes, I do use the seeds, not dried though!
I grow Blue Mystery peppers which are a wild type of pepper. Since they are so small I dry with seeds and grind them all up.
I did about 6 varieties, included seeds, in the Krups. The thicker-walled Jalapenos were not as thoroughly dried and the powder caked a bit, used those in 2-3 years. The Habanero and Scotch Bonnet were still potent and had their fruity flavor after 10+ years. Just checked my remaining freezer supply–1 bottle Scotch Bonnet dated 1998 and 2 bottles Bulgarian Carrot dated 2011 still show all powder is loose.