In a bowl blend all of the flours together. Store in an airtight container.
Notes
The xanthan gum is optional, but if you leave it out then you will need to add it when creating your recipes. The general rule is 1 tsp of xanthan gum for every 2 cups of flour. It's honestly easier to add it and not have to worry about it.In place of xanthan gum you can use guar gum or psyllium husk. Psyllium husk will alter your results slightly, but it is a great alternative if you are sensitive to gums.