Yes, those numbers on the bottle tell you how likely you are to get tanked. But more importantly, they hint at what the liquid inside tastes like. Make sense of it all, and you unlock the potential to find your perfect bourbon.
It’s a freezing winter night in early February, but inside a chic restaurant perched atop a tower in Manhattan’s labyrinthian Financial District, Jim Gaffigan is regaling a crowd of liquor journalists and whiskey aficionados with a story.
He and fellow comic Jerry Seinfeld were doing shows together. At a stop in North Carolina, they plopped down at the bar in their hotel — “It rhymes with ‘Four Seasons,'” Gaffigan quips — for a drink. “Get whatever you want,” Seinfeld said. So, Gaffigan, a comedian by vocation but a bourbon nerd by avocation, looked up and down the ceiling-high shelves until his eyes fell upon a bottle he’d never tried before: King of Kentucky.
“It might be $50, $75, $100 bucks a pour, but Mr. Seinfeld can handle that,” Gaffigan tells us.
He ordered it, the bartender poured it, and he drank it. It was good. Really good. Life-changingly good. So, Seinfeld encouraged him to order another. When the bill finally came, the price was a bit more financially irresponsible than they expected: $500 a pour.
King of Kentucky is now Gaffigan’s favorite whiskey brand, and not just because it gave him a great tale to tell at Seinfeld’s expense. It’s damn good. Created in 1881, King of Kentucky is named after horseracing, sometimes referred to as “the sport of kings” back in the day. Brown-Forman, the spirits company behind other bourbons including Old Forester and Woodford Reserve, revived the brand in 2018 to widespread acclaim. It’s now what’s called a unicorn: a bourbon that’s exceptionally elusive and exceedingly expensive to procure.
It’s also a perfect bourbon to explore one of the subtlest, most nuanced, and least understood parts of the whiskey-making process: dilution. King of Kentucky is typically released as a single-barrel bourbon, which means that the distillers pick one exceptional barrel from their warehouses and bottle its contents at barrel proof for a limited edition run. Depending on the year, the single barrel could clock as hot as 130 proof. This time around, however, King of Kentucky has released small batch whiskey, which is made from the juice of multiple hand-selected barrels blended together, which allows the company to release more bottles. And instead of bottling at barrel-proof, they dilute the yield with water — standard practice for most bourbon — to three different proof points.
We journalists were there to bring reportorial rigor to an important question: How does a whiskey’s character change depending on the proof point, and why? As Gaffigan wrapped up his speech with a toast to the new whiskeys, our eyes shifted to the bar, which was lined with dozens of half-full Glencairn glasses separated into three groups. It was time for an experiment.
“Proof” as a term hails from 16th-century English tax laws. It has always referred to a measure of how alcoholic a liquid is, but you will not be surprised to learn that the precision of that measure has changed over time. Back then, alcohol content was tested by soaking gunpowder in a spirit and trying to set it aflame. Yes, really. If it ignited — insufficiently alcoholic liquids would simply waterlog it — the spirit was considered “above proof” and taxed higher than anything under proof. In the centuries since, the method has, duh, proven faulty, so we didn’t pull any lighters out at the King of Kentucky event. Probably best to not mix alcohol and fire anyway.
In 1816, the British government changed its method of standardization. Get your pad and pen out. From Encyclopedia Britannica: “A proof spirit was now a liquor with an alcohol level 12/13 the weight of an equal volume of distilled water at 11 °C (51 °F). This specific gravity corresponds to about 57.06 percent ABV [alcohol by volume]. This standardization became incorporated in Great Britain’s 1952 Customs and Excise Tax.”
Proof no longer referred to a simple binary — over proof or under proof — and came to be a numerical measure of alcohol content.
But the U.S., as with most things, adheres to its own system. On whiskey labels in America, percent ABV is the mandatory measurement, and proof is often printed alongside it. Study a bottle, and you’ll notice that the latter is just the ABV percentage times two. Bourbon must be at least 80 proof, 40 percent ABV, according to U.S. law.
That doesn’t mean all bourbons are 80 proof. And proof isn’t arbitrarily chosen, either. Master distillers and their tasting teams, all of whom are a cross between mad scientists and wizards, meticulously consider alcohol content through relentless testing. Depending on proof, bourbons change in depth of flavor and complexity and, indeed, how much they “burn” your palate. Some whiskeys are even considered “hazmat,” meaning that they’re so high in alcohol content, over 140 proof, that they’re too dangerous to bring on airplanes.
When making bourbon, whiskey makers have to decide the distillate’s alcohol content before they age it in barrels. This is called “barrel entry proof.” Historically, the legal max barrel-entry proof was 110. Distillers typically barreled whiskey around 100 proof — until 1962, when a new U.S. law raised the limit to 125.
Why does that matter? Because the whiskey that exits the barrel is not the same as what went in. The longer whiskey ages, the more of the liquid evaporates. You’ve probably heard this called the “angel’s share.” That can actually change the proof of the juice all on its own, depending on some pretty complex science that determines if what evaporates is more water or more alcohol. But more importantly, losing the angel’s share leaves less liquid in the barrel. To increase yield during the bottling process, whiskey makers dilute the bourbon with water, therefore lowering the proof. Thus, the barrel-entry proof is a crucial starting point for determining how hot the bourbon is that ends up in the bottle.
If water isn’t added before bottling, then the bourbon is considered “barrel-proof” whiskey, like the usual single-barrel King of Kentucky release. Barrel-proof whiskey has a certain aura, but it doesn’t always turn out magically delicious. There are a multitude of factors — age, temperature fluctuation, location in the rickhouse — that can cause bourbon to become “over-oaked.” If you’ve ever sipped a whiskey that tastes like wet wood, you know exactly what I mean. It’s astringent, bitter, strange. And it’s caused by polyphenolic compounds in the barrel, better known as tannins. In healthy amounts, those compounds add flavor, but distillers must treat them delicately to achieve a pleasingly sippable spirit.
So, when distillers add water to bourbon once it leaves the barrel, they’re not just making more whiskey to sell. They’re also playing with flavor and avoiding over-oaking. Or, as Andrea Wilson, master of maturation for Michter’s Distillery, said in an interview with Whisky Advocate: “I think about it like wine; when you decant and let it breathe, it is taking on oxygen, allowing the flavors to really open up and shine with a robust, rich, smooth flavor.”
But what does that mean in practice? I and all the other journalists back in our bourbon ivory tower were about to find out. We had three King of Kentucky bourbons sloshing around in three separate Glencairns, each of which came from the same group of barrels, but was diluted with a different amount of water.
Some facts before the flavors: all three King of Kentucky Small Batch bourbons — named, fittingly, Batch 1, Batch 2, and Batch 3 — are made from a blend of the juice of barrels aged 12 to 18 years. According to the brand, some of those barrels experienced intense evaporation. In one case, just 16 percent of the original liquid was left behind. That’s not much to play with. No wonder these bottles are market priced at $300. (And no wonder Seinfeld was on the hook for such a big tab when Gaffigan sipped an undiluted barrel-strength edition.)
Batch 1 has the lowest proof point of the bunch, 105. On the nose, I whiff vanilla icing, marshmallow, brown sugar, spice, and stone fruits. The palate tastes of toasty oak and coconut, leading into a spicy, silky finish after I swallow. It’s good. But I’m a bit of a proof hound. I want to taste the hotter stuff.
So I reach for Batch 2, 107.5 proof, swirl it in the glass, and inhale its aromas: Butterscotch, baking spice, vanilla. On my palate, it’s sweet and chocolatey before dark fruits arrive. I experience a sharp, spicy finish — like red hot candies. I like this one. But I’m ready for one more.
Batch 3 is the hottest at 110 proof. My nose might be a little fatigued at this point, because I don’t experience much upon a sniff. Vanilla icing, mostly. But it’s all brown sugar and oak on the palate, with a hint of dark chocolate. After I swallow, I’m met with a long, spiced oak finish.
The second batch ends up my favorite, but overall, I’m impressed by just how different the three are. Though the typical bourbon notes are present throughout — oak, vanilla, baking spice — each one had its own unique character. Batch 1’s silky finish was more than memorable. Batch 2 had, in my opinion, the most balanced tasting experience overall. Batch 3 had a decadent, dessert-like palate. These differences are a testament to the experiment; proof really did change their profiles. But, as I recognize, so does the tasting experience.
I’m hanging with whiskey nerds on the top floor of a skyscraper that overlooks the twinkling Manhattan skyline. I’m sure some of what I’m drinking in with my eyes is influencing what I’m tasting on my palate. But that rarified situation is not the only way to find your ideal proof point. You can just as easily experiment in your living room surrounded by a few friends. Sure, none of them is Jim Gaffigan, but they’ve got their own tales. And you don’t need King of Kentucky to drink like royalty, either. Old Forester, the distillery behind King, offers multiple delicious bottles below the $60 mark, many at different proof points. Pick up a few. Crack them open. Test ’em out. Compare favorites. And plan to do it again sometime. That’s the one experiment that never fails: Bourbon is best enjoyed with good company.
