Like Bourbon? (Of course you do …) Here are a few lesser-known facts about this now-popular aged spirit that might just make you a bit more popular among your whiskey loving friends.

1) Bourbon must be made from at least 51% corn. Why? Because it’s the law.

In a 1908 court case, Justice Robb of the United States Court of Appeals of the District of Columbia wrote “it is well understood that Bourbon whiskey is a Kentucky product made principally out of corn, with sufficient rye and barley malt added to distinguish it from straight corn whiskey.” Source.

President William Howard Taft refined the definition on December 27, 1909, deciding that bourbon is “made from mash that consists of at least 51% corn (maize),” “distilled to no more than 80% alcohol by volume, and must then be aged in new charred-oak containers.” Source.

(See a cool announcement about the Taft Decision from The Chicago Daily Tribune here: “After the president had taken part in opening the Christmas stockings in the morning he went to the executive office and passed the remainder of the holiday in writing his declaration.”)

The Code of Federal Regulations (1969) compiled the stipulations: “‘Bourbon whisky’ … is whisky produced at not exceeding 160° proof from a fermented mash of not less than 51 percent corn, rye, wheat, malted barley, or malted grain, respectively, and stored at not more than 125° proof in charred new oak containers.” Source.

Boom. Lawyered.

2) Corn gives bourbon its sweetness.

During fermentation, starch converts to sugar and sugar converts to alcohol. Corn contains the highest level of starch of the grains used to make bourbon and therefore has the highest yield of alcohol per bushel.

In addition, although the law stipulates 51%, most bourbon mash bills have a higher corn content (anywhere from 60 to 80%). For example, Maker’s Mark contains 70% corn, 16% soft red winter wheat, and 14% malted barley. (See a list of various mash bills here.)

Malted barley means the barley has been soaked, sprouted, then dried — germinated in order to release pent-up enzymes. These enzymes help turn the starches into sugar. Wheat, a quieter grain, allows the sweetness of the corn to shine through; rye, more brassy, will result in a spicier spirit.

3) The barrel shortage was real.

In “The Impending Bourbon Shortage” I mentioned that with the bourbon boom, an influx of craft distilleries, and the shrinking of the logging industry, we were running out of barrels.

Adam Spiegel of Sonoma County Distilling Co., who has had barrel contracts since 2010, recalls cooperages turning down distillers at the gate.

“Earlier this year and late last year, all these new distillers came out of nowhere asking cooperages for more barrels. But the cooperages only had wood contracts for a certain amount of poundage. They ran out and had to ration what was left.”

Admittedly, the barrel shortage primarily affected small distilleries. But it spurred a barrel-making revival: existing cooperages have expanded and new cooperages have formed — many sourcing wood locally, like Rogue Spirits which opened their own cooperage in Newport, Oregon.

“We wanted to know what would happen if our Oregon crafted beers and spirits, mashed and brewed with Oregon ingredients we grew ourselves, were aged in barrels we coopered with white oak from the same terroir as our farms, brewery and distillery.”  (Source.)

4) Charred-oak literally means the barrels are set on fire.

The barrel is burned on the inside, which creates a charcoal layer. The thickness of the charcoal layer can vary based on the length of the char: a No.1 Char is 15 seconds, No.2 is 30, No.3 is 35, and No.4 is 55 seconds. Source.

The charcoal layer has several effects. First, it acts as a filter and absorbs undesirable flavors. “The molecules that make young whisky so harsh are drawn to the barrel’s wall, creating a thin layer of everything you don’t want in a drink.” Source.

Second, the char adds color. This has led to a new trend of over-charring barrels. “Whiskey comes from the still completely white,” says Spiegel. “Imagine soaking water in charcoal — if the barrel is super charred, you get color faster, but you also get charcoal flavor. It might look old, but it could have been aged for only six months.”

Third, the wood releases flavors — and charring speeds up the process. Hemicellulose, or wood sugar, caramelizes on the inside of the barrel; lignin breaks down into vanillin (guess what flavor that produces); oak lactones result in coconut undertones; and tannins, or wood spice, give you a headache. (Just kidding. Tannins make the whiskey dry. And give you a headache.)

5) The angels get a share … but the devil also gets a cut.

As bourbon ages inside the barrel, a percentage of the spirit is lost to evaporation. This is referred to as the Angels’ Share. Why? Perhaps an ancient distiller filled his rackhouse with barrels, and prayed that God would send a guardian angel to watch over every cask. Then, he came back and found his 20-year-old whiskey had lost 40% of its volume. While the dratted angel waited for the spirit to age, he must have taken a sip! And then another…

Depending on the climate, more alcohol or more water is lost during evaporation. In dry, hot climates barrels lose more water; in cool, humid climates barrels lose more alcohol. And these climates can exist within the same rackhouse. In Kentucky, the top floors are dry and hot and the bottom floors cool and moist. Distillers even things out by rotating barrels (Maker’s Mark still rotates its 500-pound barrels by hand) or by mixing barrels pre-bottling.

(Or if you’re lucky like Spiegel, your barrels have consistent evaporation. “Sonoma County Distilling Co. is 15 miles away from the coast. We get fog in the morning, it burns off by midday, and then fog in the afternoon. This gives us a very even-keeled angel’s share.”)

The Devil’s Cut refers to bourbon that remains trapped inside the wood of the barrel after it has been emptied. Jim Beam made the phrase popular when it extracted the bourbon, blended it with extra-aged stuff, and bottled it at 90 proof “for robust, premium bourbon with deep color, aroma and character.” Source.

6) Finally: Bourbon does not have to be distilled in Kentucky.

There is a common misconception that, to have the name, bourbon must come from Kentucky (perhaps because it originated in or close to Bourbon County, KY) but it must only be made in the USA.

In 1964, the United States Congress declared bourbon “a distinctive product of the United States.” Source. And the Code of Federal Regulations states that “‘bourbon’ shall not be used to describe any whisky or whisky-based distilled spirits not produced in the United States.” Source.

7) (Bonus!) But the only thing you really need to know about Bourbon…

Is that you need a glass — especially after this. In fact, so do I.


Meaghen Hale

Meaghen does a lot of work online: writing, teaching, editing. "The life!" you might say. "You never have to leave the apartment!" True. But there came a time when her pyjamas simply needed to be washed and the imperial stare of her laptop became too much to bear. So she ventured out into the world and then back inside – to a bar. And then she jumped behind it. Now she pours pints and mixes martinis for a group of regulars, and spends her free time experimenting with, learning about, and drinking craft cocktails.