The America’s Test Kitchen Gluten-Free Flour Blend requires five ingredients, one of which is white rice flour. Here's why.
The America’s Test Kitchen Gluten-Free Flour Blend, which we use in our gluten-free pizza recipe and in our new book The How Can It Be Gluten-Free Cookbook, requires five ingredients, one of which is white rice flour. When developing the blend, we discovered that the grind size of white rice flour is not uniform across brands. The flour from Arrowhead Mills was more coarse (with grains the size of semolina), while flours from Bob’s Red Mill, EnerG, and Living Now were more fine (with grains similar to all-purpose flour). This difference can dramatically affect the final results of baked goods, since coarse-ground flour absorbs liquid more slowly than fine-ground flour.
We found that using a flour blend prepared with coarse white rice flour from Arrowhead Mills is most problematic for quick breads, cakes, and cookies. Because these items are baked shortly after mixing, the flour doesn’t fully absorb the liquid and fat before baking. Doughs and batters will be soupy, and the cookies will be flat; quick breads will sink; and muffins and cupcakes won’t dome. The long proofing times required for yeasted loaves allow for better liquid absorption, which alleviates many of these problems, but the loaves still won’t dome perfectly. In all these cases, we recommend preparing the blend with fine- ground white rice flour (Bob’s Red Mill is our favorite and most widely available). However, we found both batches of blend delivered acceptable pizza crusts, due to the combination of the dough’s proofing time and being rolled thin. If you are mixing up our blend to make only our gluten-free pizza, you’ll be fine using either coarse or fine rice flour.