We roast over a very hot grill to get the "skin" of the chile to bubble up, think major second degree burns. They have to be turned over a couple of times and bringing the lid down roasts them faster.
Then we lay them out on a table covered with newspaper to cool down. After 15 minutes or so we put about a dozen in quart size freezer bags, get all the air out and zip them closed. Another 20 minutes and then stack them in the freezer.
They will keep up to two years. We just peel them when we defrost them instead of doing them all at once.
Whittier, CA, USA
Dona nobis pacem