1. Buy chestnuts. Let them sit for a good long time until they're very dry.
2. Decide to make chestnut flour with the chestnuts.
3. After peeling the chestnuts (having a lot of wine on hand for this process is helpful), break up the pieces with a mallet or hammer.
4. Put the pieces into the grain mill. When the pieces are too big, take them out again, spilling some on the floor (drink more wine) and hit them some more with a hammer.
5. Decide that using the blender might be a more efficient way to break the pieces up enough to go through the grain mill.
6. Put hard, dried pieces of chestnut into blender.
7. Cover ears.
8. Turn blender on.
9. Wait for speeding chestnut pieces to crack a hole in the blender and send bits of chestnut shrapnel flying out the hole. (Do not stand in the path of chestnut shrapnel.) (Drink more wine.)
10. Go back to using a hammer.
11. Buy a new blender.