Editor’s note: This is the first of a two-part series by columnist Doug Skinner about the process of making bourbon barrels and bourbon.

By Doug Skinner

Bourbon. Pappy Van Winkle, Woodford Reserve, Blantons and Buffalo Trace to name a few brands. Nothing will bring a group of men (and women) together quicker than announcing that bourbon is being served.

Nothing will divide that same group of people quicker than a discussion about bourbon; how it is made, what gives it its flavor, where it is made, what bourbon is the best, single barrel versus double barrel versus blended barrel, and whether to drink it plain, on the rocks or, God forbid, with Dr. Pepper.

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Even Mark Twain remarked, “If I cannot drink bourbon and smoke cigars in heaven, then I shall not go.”

As one Kentucky bourbon expert told me, how you drink bourbon is between you and the bourbon, for there is simply no wrong way.

I took a recent hard-to-come-by visit to the Brown-Forman Barrel Company in Louisville, Kentucky, which was followed by a trip to the easily accessible Woodford Reserve Distillery in Versailles, Kentucky, owned by Brown-Forman.

Before the bourbon gets to our liquor cabinet, many steps are taken before it achieves its unique taste. Bourbon is a product defined by federal law, produced in the United States, though not exclusively in Kentucky. It is made from many grains but must be at least 51 percent corn. Law requires that bourbon must be aged in new, charred oak barrels.

Today we will discuss the barrels, critical in the storage, transfer, aging and flavor. In fact these 53-gallon barrels weigh 500 pounds when filled with bourbon at the distillery and account for 50 percent of the flavor of bourbon.

Brown-Forman director Michael Nelson explains that from early history, barrels have been a useful form of storage and shipping. Nearly every town in America had a cooperage where skilled barrel builders called coopers took wood staves and assembled them into barrels.

These coopers understood the unique differences between trees, and oak was sought out as an important source for barrels, boxes and crates. Even among oak trees there is a difference. Red oak barrels would not hold liquids but allowed an exchange of air, necessary for dry goods to ventilate and not develop molds. White oak was nearly impervious to liquids, and these barrels kept liquids from seeping out for long periods of time due to a chemical in the wood called tyloses. A quarter-sawn cut to the wood gives the wood grain a profile to aid in holding the liquids. Due to the abundance of these oaks at the time, it was natural to use the white oak for bourbon.

Of course forests have been cut down over the years, and now most of the American white oak comes from areas ranging from Minnesota to Alabama and east to Virginia. Fear not, fellow bourbon drinkers: the American white oak is very sustainable for our purposes.

When talking about bourbon, Nelson stressed that a barrel is not a container, rather an ingredient. But it is three years before this ingredient is cut down as a tree, seasoned in open air, kiln-dried, planed, steamed and cupped to become staves. Fit together by hand and bound by metal hoops, these staves of varying widths are fit together like a puzzle by a master cooper, who can make 200 barrels a day. Brown-Forman is the only major bourbon distiller that makes its own barrels.

Once a barrel is made, it moves to a toasting room, a secret, proprietary method that I was not allowed to view. Here, the inside of the barrel is lightly toasted, which pulls the sugars and other flavors towards the heat. There are 350 volatile compounds occurring naturally in the wood.

The toasted barrels return, and the inside of the barrel is exposed to a large hot flame for a few seconds. These flames char the sugar and other compounds that the toasting previously drew out of the wood. Together these two processes bring out the flavors of vanilla, caramel, nutmeg and cinnamon, just to name a few.

It is the wood that gives bourbon its characteristic color and 50 percent of its flavor. When you drink — nay, sip — bourbon, you are tasting the entire history of the tree. Amazing.

The barrels are then shipped to the Woodford Distillery in Versailles to be filled. There it is labeled, dated and moved to stone warehouses built in 1890 and stored on shelves called ricks, usually for six years or more. Woodford’s four warehouses can store 200,000 barrels. In fact, there are 5.5 million barrels of bourbon stored across Kentucky, a state with a population of 4.5 million. But as a forlorn country song cries, “There ain’t enough bourbon in Kentucky for me to forget about you.”

Law dictates that a barrel can be used only once for the crafting of bourbon, but its life is far from over. It will be sold to manufacturers of whisky, rum, tequila and shipped overseas for the production of scotch and wine. By the time they are cut in half and sold at discount stores as flower containers they may be 100 years old.

Next, learn about the process of crafting fine bourbons; a primer for some, a review for others, but certain to cause people to voice their knowledge.