When selecting chestnuts in the store, look for deep colored nuts with significant striping. Press the nut between your fingers. It should be solid - no give. A retailer who really knows about chestnuts will not display them with the other nuts in the produce department, but will display them on the cold rack. Stay away from dull powdery surfaced chestnuts. This is a sign of mishandling and they are beginning to mold.
At home, store chestnuts in the refrigerator. Remove them from the refrigerator two to three days before roasting. This gives them a chance to dehydrate a little which makes them fluffier when roasted.
Preheat oven to 350 F. Be sure to cut an "x" on the flat side of the nut with a sharp knife and make sure it cuts entirely through the shell.
Place the chestnuts on a cookie sheet and put them in oven - 30 min for small chestnuts, 40 min for larger chestnuts. While chestnuts are roasting, dampen a clean towel and lay it out on the counter. Place chestnuts on the towel and fold over for a bout five minutes. This will keep them moist and make them easy to peel.