Coconut flour consists of the white ground flesh of dried coconuts, the kind with a hard brown shell most often found in North American grocery stores. Producers manufacture coconut flour by draining the pulp of oil, then grinding the flesh into powder. Coconut flour is gluten-free, making it a popular flour for people with coeliac disease or allergies. Organic groceries stock the flour because its high protein makes it a convenient health food.
It is difficult to find coconut flour substitutes because coconut flour is heavier and more dense than most flours. Recipes that use coconut flour cannot be reproduced exactly with the same proportion of flour substitute, meaning that your recipe with substitutes will probably need significantly less liquid than you would need with coconut flour. Plus, you may be intolerant of wheat-based and non-wheat flours, as is the case the for many who purchase coconut flour.
If you tolerate wheat, it is easy to substitute wheat flours. The rule is that you can substitute white flour for about 3/4 of coconut flour contained in the recipe. If substituting with whole wheat, replace about 1/2 of the coconut flour with whole wheat. If the mixture becomes dry, add 1 tsp water as needed until you reach desired consistency. If the mixture becomes too moist, add 1 tsp wheat flour as needed until you reach desired consistency.
Gram, or chickpea, flour is a gluten-free, protein-rich flour that can work as a substitute. Like coconut flour, gram flour is very dense. Your batter or dough should reach approximately the desired consistency if you substitute exactly. Add a pinch more of gram flour or a splash of water as needed. The difficulty is that gram flour has a nutty flavour unlike the subtle sweetness of coconut flour. Its use as a substitute will prove largely a matter of personal taste.
Oat flour works, but be careful if you maintain a gluten-free diet for health reasons. Producers often process oats on machines used for wheat flour and other allergenic foods. Read the labels to check for contaminants. If the label does not state whether or not the product is gluten-free, request a list of gluten-free and non-allergenic foods from the grocer. Add 1 extra tbsp oat flour for every 1 cup of coconut called for in the recipe. Add a few drops of water if too dense.
Almond flour is a popular choice because of its health benefits, but it makes a poor substitute for coconut flour. Its light consistency means that you must add a substantial amount of extra flour when substituting for coconut. Try 1 1/3 c. almond flour for every 1 c. coconut flour that the recipe includes. Also decrease the recipe's liquid by about one third. If needed, add water 1 tbsp at a time at the end.
Try other flours if you like, keeping in mind that you may need to increase both fat content and liquid when you replace another kind of flour with coconut flour. Coconut flour can very easily turn your baked item chewy and heavy, so be careful to include enough moisture. A well-written recipe describes the consistency that you should approximate, though judging the right consistency for your batter or dough requires some trial and error as you become more comfortable with the basics of baking and cooking with flour.