Things You'll Need
Hole-sawing drill bit
The art of barrel-making is called cooperage. Coopers construct whiskey barrels from oak (specifically white oak, in America), which imparts flavor and color to the whiskey inside. Barrels are constructed without the benefit of nails, screws or other fasteners. They are merely wood staves held in place by metal bands, meaning exceptional craftsmanship is necessary to make barrels watertight (or whiskey-tight, as the case may be). It can take years of practice for a cooper to become proficient at barrel-making.
Cut down an old growth white oak tree and quarter the trunk. Cut 36-inch long, 1-inch thick boards from the quarters, making sure to cut all boards radially (across the tree's growth rings, not tangentially to them). Stack the boards in tiers and season them for at least three years to reduce moisture content.
Taper the ends of the boards and angle the sides so that they will fit together snugly when placed next to each other in a cylindrical barrel shape. Plane the outside of each stave and hollow the inside slightly.
Clamp the tops of two staves on opposite sides of a 21-inch diameter metal hoop, then stand the staves upright with the hoop on top. Insert more staves around the inside of the hoop until they fill it snugly. Pound two slightly larger hoops onto the barrel (towards the middle) with a mallet to hold the staves in place.
Brush water onto the inside of the barrel and light a fire on the ground inside it. Run a loop of cable around the bottom of the barrel (where it is still too wide) and slowly tighten the cable with a winch as the barrel heats, over a period of a few hours. When the staves are closed at the bottom, pound a 21-inch metal hoop over the bottom end and remove the cable. Pound two slightly larger hoops onto the bottom half, so there are six hoops on the barrel in total.
Place the barrel on its side and make a fire inside it. Turn the barrel, distributing the burning material over the inside surface until it is completely charred. Drill a bung hole in the side.
Cut a groove around the inside of the staves at the top and bottom, using a router. This will hold the top and bottom in place. Cut two matching circles of white oak boards using a jigsaw. Remove the top and bottom hoops from the barrel, and pry the staves apart far enough to insert the top and bottom boards so they are seated in the grooves. Replace the hoops.
Whiskey barrels are charred inside to a much greater degree than wine barrels. Without this charring, they will not impart the correct flavors to the whiskey.
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