Years ago, drinking ultra high-proof spirits was the type of behavior reserved for frat parties. It meant braving some pretty harsh liquids—Everclear perhaps, or some other grain alcohol—for the chance to prove your manhood and get drunk in a hurry. It was not the stuff of sophistication.
Today, the terms “barrel proof” and “cask strength” are spoken in reverent tones among connoisseurs of fine spirits, and there’s nothing unsophisticated or rough about such drinks. People look to these stronger, more intense spirits in search of fuller, deeper flavors and a kind of authenticity. After all, isn’t straight from the barrel the way that the liquor gods intended for it to be drunk?
The answer may be complex, but the vogue for higher proof is certainly clear as it has spread not only among American whiskeys such as Bourbon and Rye, but into other categories that had tended to toe the line at or near the legally mandated 80 proof minimum (40 percent alcohol by volume) for most spirits. If you think of Irish whiskey as easygoing at that low strength, get ready for something with intense flavors and a grip when you sample Redbreast’s 12-year-old cask strength at more than 116 proof, or the Connemara’s cask strength, which shows plenty of spice and fruit. The overproof rum you’ve sampled in the past might have been clear and throat burning, but Mount Gay’s Port Cask expression (110 proof) is an amber-colored mix of molasses, rich fruit and nuts.
What is, essentially, the same quaff can be quite different when sampled at different proofs, and that doesn’t simply mean that cask-strength examples taste stronger of alcohol. Want to test the theory? Simply compare a standard, 80-proof whiskey at 80 proof against its bottled-in-bond version. As well as getting an extra kick, you may notice a marked flavor boost. That effect has been known to drinkers since the bonded designation—which stipulates a proof of 100—was introduced in 1897. But the century mark is not by any means the highest proof possible, and Bourbon producers have been thrilling the whiskey cognoscenti by testing the outer limits for quite some time, at least since Jim Beam introduced the high-octane Booker’s at 120 to 130 proof back in 1988.
Bottle proof depends largely on how purely a spirit is distilled and how much it is diluted afterward, and understanding the allure of a cask-strength spirit begins with how said liquor is born. Most spirits begin life as a beer or wine (beer for whiskey, wine for brandy). Each imparts its own flavor. The next step, distilling, is the process of separating the water from the alcohol by steaming off the latter and condensing the vapor by cooling. Distillers can choose how pure they want the alcohol coming off the still to be.
Theoretically, the purest would be 200 proof (100 percent alcohol), but practically, it is more like 190 proof. That’s how grain alcohol is made. But distilling to that extreme is a process that strips the liquid of all its plant-base flavors (unless you consider the grape juice added to make Purple Passions at toga parties). In the case of vodka, that’s what you want. Aiming for a tasteless and odorless spirit, you might distill the product as many five times, then dilute it with water to reach its bottle strength.
But in the case of, say, whiskey, the flavor of the grain base is part of the charm. That’s why Bourbon regulations set a ceiling of distilling to 160 proof (80 percent alcohol) and also why some distillers don’t even approach that. Wild Turkey, for example, distills as low as 55 percent. So you have a sort of push and pull with whiskey: distill it at lower proof and you get more flavor, but bottle it at higher proof (i.e, add less water) and you showcase the flavor that it drew from its base and intervening aging process.
A third process, far less predictable, also determines proof: evaporation. Its effect depends on a number of things including the weather, the condition of the cask and its location in the warehouse. Proof can rise or fall depending on the humidity as either the water or the alcohol evaporates faster. Therefore every barrel is dumped at a different proof and tastes slightly different. For consistency, they are melded together in batches and—usually—water is added to get the correct proof. Of course, in the case of cask strength, that last step is skipped.
But the notion that there is a preordained alcohol content for cask strength is specious. Most makers distill to a standard proof and after the spirit goes in the vessel they wait for it to take flavor from the wood. They dump it when it tastes right, not at any set proof. That’s why the stated proof of a cask-strength product may vary from bottle to bottle or batch to batch.
However, the charm of a cask-strength offering is not simply in the fact that no water has been added to weaken the flavor. Casks or batches of casks are chosen for barrel-proof presentation because they are inherently tastier than most others. The spirits maker has decided to share them with the world undiluted to showcase the flavor. In the case of Angel’s Envy, even while it carries a standard Port-finished version, it releases a new one at near 120 proof each year picked for outstanding qualities. And each one has beguilingly different effects.
However, that kind of treatment isn’t for every cask, nor for every drinker. Most of the imbibing public is fine with drinking at tamer levels like the popular 80-, 86- and 90-proof marks. The big rush of alcohol that comes at percentages higher than 100 proof can be off-putting to many. And even whiskey geeks will tell you that it’s a good idea to add water to a cask-strength expression. The H2O serves to open up the spirit, much as letting a wine breath unleashes its flavor. But the point of cask strength is also that the drinker, not the producer, gets to determine how much water to add.
Cask strength has pervaded the spirits categories. The high-proof movement grew out of the Bourbon world as it was used to show off the delightful variations in a category that seemed stale next to single-malt Scotch, which was the rising star of whisky. Although it wasn’t trumpeted as much, Scotland has long had cask-strength options. In fact, if you’ve been lucky enough to taste a malt as old as 40 years it may be devoid of added water, even though its proof is meager, as evaporation has taken its toll. But they go much higher, with interesting effects. BenRiach’s Peated Cask Strength edition is coyly sweet at 120 proof and to get the full smoke you need to add water to break it out. GlenDronach Cask Strength is so fruity on first sip that it’s hard to identify as Scotch.
It’s not surprising that straight rye, the spicy, reborn cousin of Bourbon, has followed suit with cask-strength variants. Templeton Rye Barrel Strength gets a welcome blast of licorice at 113 proof and Larceny is positively fruity at 122. But it is somewhat of a shock when Canada follows suit as their spirits are often prized for their smoothness, a quality that eludes most high-octane expressions. However, Lot No. 40’s cask strength is supremely earthy and shows off the rye character Canada was known for in the past. Similarly, Hommage a Yves & Jean-Noel Pelletan, the rare cask-strength Cognac, has a boldness that belies the softly nuanced quality its category is known for.
What can’t be questioned is that cask-strength spirits have made their mark across the liquor-sphere in ways that are well worth pursuing. Just don’t waste them on your fratboy friends.