Sift the tapioca starch, brown rice flour and potato starch into a large bowl. Mix together thoroughly using a large spoon and/or whisk. The flours are properly blended when the mixture is a uniform colour with no streaks of individual flours visible.
Transfer to an airtight container and store in a cool, dark pantry.
I usually try and take note of the best-before dates on each of the flours and label the flour blend with the earliest of those dates. But provided the flour is stored correctly it will generally keep well for several months.
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Notes
You can scale this recipe up or down to make the amount of flour you need. Simply multiply the total weight of flour needed by the percentage of each component flour.Tapioca starch: 50% | Brown rice flour: 40% | Potato starch: 10%If your calculator doesn't have a percent option then use the following example, changing the "500" for the total amount of flour you need:500 x 0.50 = 250g tapioca starch500 x 0.40 = 200g brown rice flour500 x 0.10 = 50g potato starchIf you're making a larger batch of flour, you may need to split the ingredients and mix them in two batches, or use a larger bowl or saucepan to mix them in. I use our huge pasta pot for larger (2kg+) batches.Xanthan GumIf the recipe you use want to use this flour blend in is already gluten free, then check to see if there is already a gum (usually xanthan or guar gum) listed in the recipe. If there isn't then I generally suggest using 1/2 teaspoon of Xanthan gum for an average-sized cookie recipe, or 1 teaspoon for an average-sized cake. If you make the recipe and the end result is crumbly, then increase the gum next time. If it comes out gummy or rubbery, then reduce it.