Let’s clear something up right off the bat: oats are naturally gluten-free.
They become non-gluten-free when they are processed in facilities that mill other gluten-containing grains such as wheat, barley or rye.
If you must eat gluten-free, choose certified gluten-free oats for making oatmeal, using in recipes and for flour. These have been processed without risk of contamination, ie. infiltration of gluten from other grains.
Making your own oat flour is a cinch. All you need are oats (rolled or whole groats) and a blender, regular or high-speed such as a Blend-tec or Vita-mix.
Put 1 cup of rolled oats in blender container. I love my Blendtec and highly recommend these high speed blenders.
Whiz up until all is a powder. In a regular blender, you may need to stir up the flour from the bottom of the container midway through the process so that all of the oats get pulverized.
Store in a glass jar in the refrigerator.
So many options. Enjoy them all.