Gluten-free culinary starches
Grains have protein and starches. When you take away the protein, you are left with starches. The most popular starches are cornstarch, tapioca starch, arrowroot starch, and potato starch. The starches don't have taste. They are used to thicken liquids and to add volume to baked goods. Even with all the thickening qualities, starches alone won't keep your baked goods from falling apart.
Starch tends to lump together when warmed up, so mix it with cold liquid in a separate cup before slowly adding it to the warm liquids. If your meal becomes too thick, try heating it again.
If you are making gravy or soup, keep in mind that cornstarch will make it look clear and less creamy than if you would use wheat-based starches.
Low-protein Gluten-free flour
Some grains are naturally low in protein. Corn, rice, and millet fall in this category. Flour made from these grains will also be low in protein. If you use these types of flour in your baking, you very well know that your products are not held together. Try using a mixture of a few different low-protein flours.
Rice flour is probably the most common kind of low-protein flour for gluten-free baking. It is not expensive, is widely available, and offers mild taste. It can be a bit gritty and needs to be stored in the refrigerator.
Millet flour is less common, more expensive, and has better taste than rice. Corn flour, not meal, has soft, fine texture, but the taste is stronger.
Low-protein flour can be used for thickening sauces, coating meats for frying, making tempura, and baking flat breads.
Amaranth, quinoa, sorghum, teff, and buckwheat are all low-protein, but they have strong taste, which makes them less universal. Try using them when you want to taste them or combine them with high-protein grains.