Combine all ingredients in an airtight container and whiskwell to fully incorporate. (I like to put the lid on and shake it several times as well).
For larger amounts, simply slide the serving amount slider to the right to get the proper amounts for each flour component (I make 2.8kg at a time).
Store in airtight container in a cool, dark pantry or closet. This mixture will keep for up to three months if well sealed.