I was advised to add the darkening effect, and oak aging to my whiskey, all I had to do was cut some white oak into 3/4"x3/4"x4" blocks, and char them with a blow torch. Then put a couple in a quart jar with the wash for about a week. I did that and it turned out pretty good. Now in doing more research, I'm finding that there is a real science to this. They should actually be baked in an oven. Some are saying to wrap the block in aluminum foil. Some people are using the pre-chared oak chips from brewing stores. I'd like to know what you all are doing if you are oak aging your whiskey, and what has worked the best for you.