Half a dozen casks go in at a time and are subjected to heat up to 1000 degrees per cask. …it’s this firing process, this charring, that imparts this most pronounced flavor into bourbon – the rich, creamy, caramel and vanilla flavors we all know.
“We can take a piece of oak and cook it 150 different ways and each way is going to create a different flavor profile.”
☞ Charring Bourbon Barrels // seguinmoreaunapa
It acts like an activated-carbon filter to adsorb sulfur compounds and it provides a passage for the spirit into the pores of the oak. In the United States a full-depth charring of barrels (i.e., 1/8 inch) used to age American straight whiskey is predicated by law. This is in spite of the fact that over-charring can actually destroy some of the flavors that are needed to develop the finish of the spirit. This is why toasting, or even a light char, may be a better route, but it is illegal in the United States to age straight whiskies, such as bourbon, in any-thing but fully-charred barrels. A medium-depth char is required just to crack the wood, and a heavier char burns up wood compounds that would only be caramelized by a low- or medium-level char. – Bill Owens in the Craft of Whiskey Distilling
Nearly all bourbons you’ll find on the shelf come from barrels with heavy char – level #3 or #4. Most of the barrels used for the bourbons in the chart below are produced by the Independent Stave Company with the exception of the Brown Forman brands. Brown Forman produces their own barrels at the Bluegrass cooperage in Louisville.
|Char #1||Char #2||Char #3||Char #4|
|Very Old Barton, 1792 Ridgemont Reserve, Kentucky Gentleman||All Jim Beam bourbons, Old Crow, Old Taylor, Knob Creek, Booker’s Old Grandad, Basil Hayden, Knob Creek Rye|
|Brown-Forman Old Forester, Woodford Reserve, Early Times, Jack Daniels||Buffalo Trace, White Dog, Old Charter, Eagle Rare, Colonel E.H. Taylor, George T. Stagg, Ancient Age, Elmer T. Lee, Blanton’s|
|Four Roses, Single Barrel, Small Batch||Everything Weller, Pappy Van Winkle, Sazerac, Bowman Rye, Van Winkle Family Reserve Rye|
|Heaven Hill, Evan Williams, Elijah Craig, Henry McKenna, Parker’s Heritage, Old Fitzgerald, Bernheim Original, Mellow Corn||Wild Turkey, Russell’s Reserve, Wild Turkey Rye|