Cut a slit in the bottom (the "pointy" end away from the stem) of each pepper.
Lay them out on dehydrator trays, so they don't touch.
Set the dehydrator to the "vegetable" setting (varies by model), about 125°F/52°C.
Let peppers dry completely, until they are brittle (about 24 hours).
Break them open, separating the stem and seeds from the flesh.
Add to food processor or juicer.
It's helpful to wear a mask over your nose and mouth, as the dust from the powder can be quite irritating to inhale!
Pulse the flesh until it is a medium powder consistency.
Transfer to an airtight container like a jar or a zip-top bag. Store in a cool, dry place.