By law, bourbon wouldn’t be bourbon without being aged in a new, charred oak barrel. It’s the source of the spirit’s color and distinct flavor. So naturally, we love our barrels. We couldn’t do what we do without American white oak barrels or our imported port finishing casks. Coopering used to be big business in America, and barrels were used to store just about everything. Today, there are only a handful of cooperages still practicing the trade, but given bourbon’s increase in popularity, they’ve been pretty busy. One of the recent bourbon shortages was actually attributed not to a shortage of spirit, but rather a shortage of barrels.
The Barrel Begins
It all starts with finding the right wood. For bourbon, the barrels have to be oak. Lumber harvested from northern U.S. regions is usually preferred, as the cooler climate often results in a denser wood grain. Over time, this can help minimize the amount of bourbon lost to the Angel’s Share. After the trees are cut down and milled, the wood needs to spend some time drying out until the water content of the wood comes down from 60% to around 12%. After the wood is properly dried—natural air-drying is best—it’s then cut into staves, steamed and formed into barrels by the cooper. A skilled cooper can assemble a barrel in under a minute, and no glues or fasteners are used in any part of the barrel.
Before bourbon barrels can be filled, their interiors have to be charred. The cooper inserts an open flame into the barrel, charring the interior for up to a minute. Angel’s Envy uses a #3 char, which is a 35-second burn. This process caramelizes the surface of the wood, making it easier for the bourbon to draw out the wood’s natural flavors. Sound like a lot of work? It is. Coopering is a closely guarded trade, and it’s difficult to master. We’re just glad that these craftsmen and women have kept the tradition alive.
The Golden Years
The barrels are filled with bourbon, and then they rest patiently on dusty racks in rickhouses until they’re deemed ready. The bourbon slowly flows into and out of the wood, soaking up flavor and color as the Angel’s Share gradually evaporates. Occasionally, barrels will need to be repaired: cracks can form or hoops might need to be hammered back into place. All efforts are focused on getting the most flavor out of the barrel while losing the least amount of spirit.
One of the legal requirements for a whiskey to be considered a bourbon is that it must be aged in new oak barrels. So what happens to the used barrels? Many of them are shipped to Scotland, as Scotch has no laws requiring new barrels. Because much of the flavor has already been leached from the barrels, Scotch tends to be aged longer than bourbon. Tequila and rum distilleries, as well as craft beer breweries also use old bourbon barrels to age or add bourbon’s distinctive flavors to their products.