When you think about making your own flour, you probably imagine harvesting grain, winnowing it, then grinding it up. It's a long (and some might say tedious) process. But making your own chestnut flour is surprisingly easy.
Chestnut flour has history. Different varieties of chestnuts grow throughout the temperate zone, and many cultures have made use of the nut as a food source. In North America, Native Americans made flour from the dried nuts and ate the whole nuts as vegetables. (That was before the chestnut blight almost eradicated our native chestnut.) In Europe, chestnut flour was generally considered a famine food, a poor person's substitute for wheat flour. Not because of taste (it's delicious) but because chestnut flour contains no gluten, which means it doesn't rise. Any bread made with chestnut flour alone will be flat, and apparently, flatbread was under-appreciated in 18th century Europe.
Chestnuts are high in carbohydrates, low in fats, and have no cholesterol. Since the lack of gluten means that chestnut flour won't rise like regular flour, try using it in flat applications, like crepes, polenta, pasta, and pancakes. It can also be substituted for up to 20% of the regular flour in a recipe to add a light sweetness to baked goods, like chestnut pound cake.
Some people call chestnuts the "grain that grows on trees." If you found an especially nice chestnut harvest this year, try making your own flour. It's easy, gratifying, and very tasty.
Making the Flour
If you've already peeled your chestnuts, skip this paragraph. If you're starting with fresh, raw nuts (I'm assuming you left those spiky shells back in the woods somewhere), use a serrated knife to make an X on the flat side of each nut, then place them on a cookie sheet. Cutting the peels allows steam to escape from the nuts and prevents them from exploding in the oven. Roast the chestnuts at 400° for 25 minutes. You’ll notice the skins start to peel back from the X. The shells and inner skin will come off easily when the nuts are still warm. If they cool down and stiffen up, zap them in the microwave for 30 seconds to reheat and make the skins pliable again.
I slice whole nuts in half before drying them to speed up the dehydration process. Spread your peeled and sliced nuts on a dehydrator sheet and dry at 105 F for 12-24 hours. If you don't have a dehydrator, dry them on a cookie sheet in your oven on the lowest possible setting. You'll know they're done when the nut pieces are so hard you can't break them in half with your fingers.
Using a spice grinder or blender, grind your dried chestnuts until the flour reaches the degree of fineness you need for your chosen recipe. If you're making polenta, stop when the flour has a texture similar to that of cornmeal. If you want to try this Chestnut Pound Cake, keep grinding until it's super fine.
Chestnut flour should be kept frozen or refrigerated. This way it can be stored for up to six months.