The go-to source of information on all things gluten-related is the organisation Coeliac Australia, with its quarterly magazine, The Australian Coeliac, (http://www.coeliac.org.au).
The December 2015 issue had an excellent article on gluten-free flours and grains, and great tips on mixing up your own gluten-free flour. While various commercial gluten-free flours are readily available now we always think it's better to make your own because you know exactly what's in it.
To replicate the characteristics of wheat in baking,gluten-free flours are usually a mix of three or more different flours. To perform well, a flour blend needs protein to interact with the raising agent, starch to thicken and bind, vitamins and minerals and, ideally, fibre. The starch is usually derived from rice, corn, tapioca (also known as arrowroot) or potato, and there’s now sorghum available too although it might be harder to find.
You can add protein to any flour mix by using eggs or almond meal but buckwheat, quinoa, coconut and banana flours have a high protein content and are high in nutrients too, so by substituting half a cup of the starch you’re using with any one of these, you’ll enhance the flavour and the goodness of the mix naturally.
The best flour combination varies according to the recipe and what you're making - breads, pastry, pancakes, biscuits etc – but it’s good to have a general-purpose flour on hand too and we’ve found the following works well.
Jan
3 cups fine rice flour
1 cup fine brown rice flour
2 cups tapioca flour
2 cups potato starch (not flour)
Mix together in an airtight container and toss it around a bit to blend thoroughly. (Makes 8 cups.)