There are whiskeys so high in proof that they are banned from being brought onto a plane by the FAA before flying due to the fact that they’re considered a highly flammable hazardous material. These coincidentally became known as “Hazmat” whiskey. Often bourbon, though not exclusively so, these 140 proof and higher whiskeys are a rare breed and have become a highly sought after subset of American whiskey. This jet fuel style of whiskey isn’t for the uninitiated, which is probably why whiskey diehards are the main group seeking them out. What led to the rise in ultra high proof whiskey and what is it about extreme proofed whiskey that draws people to it?

‍How does the proof get so high?

For a whiskey to reach ultra high proof, it helps if the whiskey that enters the barrel is also high in proof, but there is a ceiling as to how high it can initially go in at. Bourbon, and most whiskeys, cannot exceed a barrel entry proof of 125 per TTB regulations. As bourbon ages in a barrel, its proof levels change. There are many factors that account for this, with temperature being a major contributing factor. One big factor is that rickhouses are usually cooler on lower floors and hotter on higher floors, generally, barrels placed on lower floors will lose proof, while barrels placed higher will gain proof. Of course there are always exceptions.

Kings County Distillery has released a number of ultra high proof bourbons recently, and according to Master Distiller Colin Spoelman, even some of their whiskeys that are 110 and 116 proof have gone over the 140 proof mark.

“Small barrels with a lot of temperature volatility in the aging cycle will certainly head that direction. But we have full-sized barrels that climb fast too,” Spoelman said. “In our case I believe it is mostly due to our cooperage and aging climate. Humidity is a factor in how much alcohol evaporates relative to water evaporation. But we are also aging in spaces that weren't built to that purpose and using a variety of barrel formats.”

The highest proof Kings County had ever released was a 177.4 proof wheat whiskey aged 7 years in a 5-gallon barrel, which saw an 89% angel's share. Spoelman added, “I don't know that we can ever replicate that - or would even want to - but it's a fun bonus when a good whiskey has a high proof.”

The rise of barrel proof whiskey

Twenty years ago, releasing a barrel proof whiskey as an ongoing product in a company’s brand portfolio was uncommon, if not nonexistent. Even 10 years ago, there were only a few companies regularly releasing barrel strength products. There was a general notion that American drinkers preferred their whiskey in the 80-100 proof range and some of this thinking was inherited from Scotch and Irish whiskey’s long history in that proof range.

As the bourbon boom happened in the mid-2010s, more and more companies were looking to differentiate themselves by seeking out any untapped niche they could grab hold of. Single barrels, wine cask finishes, and barrel strength were suddenly the hot thing. Bigger, bolder, and higher proof quickly became the unofficial motto of many Kentucky distilleries.

Even before the boom, companies like Jim Beam, were the forebearer of the barrel proof movement thanks to their Booker’s Bourbon release, with Buffalo Trace’s George T. Stagg and William Larue Weller quickly making a name for themselves in the 130 proof range. But things changed in 2016 when Heaven Hill released batch 6 of their Elijah Craig Barrel Proof and ultra high proof whiskey became easier to obtain. Coming in at 140.2 proof, it hit the burgeoning barrel proof market like a bomb, rightfully cementing its unofficial name as the “Hazmat batch” among enthusiasts, and subsequently igniting their love affair with 140+ proof bourbon.

Why the surge in popularity?

‍Despite Hazmat bourbons’ scorching sip and resulting kick to the gut, many brands have gone out of their way to join the Hazmat club. It’s to the point where it has gotten extremely hard to even track new releases, especially with the rise of single barrel clubs.

Kings County Distillery recently released a 150.88 proof scorcher, not as a special release on their website or randomly to the market, but as part of Seelbach’s barrel club. According to Spoelman, they don’t set out to release an ultra high proof whiskey, they discover it as it's aging and then have to figure out if it aligns with their distillery’s desired flavor profile. High proof whiskey can be unwieldy and can wreak havoc on a company’s desired flavor profile target. It isn’t always, “Hey we have a high proof bomb here, let's bottle it and release it.” Companies are careful to maintain a flavor profile rather than falling for the excitement of an ultra high proof whiskey just for the sake of it.

At the same time, it's hard to ignore the excitement of a Hazmat bourbon from the consumer side. It stems less from a bottle’s given rarity from a numbers standpoint, and more from an experience standpoint. It’s similar to how people enjoy the One Chip Challenge. People like the torture, the excitement, and surprise of it.  

Often when people cite why they drink barrel proof bourbon it's because of the increased intensity of flavor. Common sense then says, higher proof equals more flavor. As one of our readers who asked to remain anonymous put it, “The flavor! Much purer and fuller than the watered down 80-90 proof whiskey. I usually save my high proof whiskeys for special occasions or the end of a tasting night. Honestly, I also think it’s a trend because as people drink a lot more bourbon, they start to lose their taste buds a bit, so they need higher proof, higher flavor whiskey to make up for that.”

Fellow reader Cole Foor added, “Typically the uncut nature of the spirit, really maximizing mouthful and allowing for you to taste and nose the most elaborate spectrum. For Hazmat specifically, I find that there is another level of uniqueness to it. Almost an overly sweet back palate profile that is addictive and alluring. The complexity usually is quite robust as well. Typically the higher the proof, the better the aromas come off.”

Keenan Wood, along with many other of our readers, tends to reserve drinking Hazmat bourbon for special occasions. “Not many people enjoyed Bacardi 151 or drink Everclear on special occasions. Hazmat bourbons are different; behind the heat you can still find the great flavors we all love about bourbon. Since not many bourbons climb the 70% mountain, my friends and I open them on holidays.”

Typically, someone’s everyday sipper isn’t going to be 140+ proof dram, so a special pour can mean special proofpoint. With the majority of the best limited edition bourbons unattainable for most bourbon enthusiasts, Hazmat bourbons can be easier to get your hands on. Demand remains high for ultra high proof bourbon, but if you’re excluding many casual drinkers that don’t have a taste for such high proof, or don’t even know to look for them, there are less fish in the pond seeking them out.

Future outlook

‍Will ultra high proof whiskey join the ranks of recent popular trends in whiskey such as single barrel, finished whiskeys, and barrel proof whiskeys? It’s hard to say according to Spoelman.

“People who make great bourbon happen to have a hot one vs. aiming a whiskey at high proof. If people start to release proof monsters for proof's sake, you'll start to see a lot less interest in them, because they won't be very good,” Spoelman said. “From a distiller's point of view, you can't really control how a barrel ages, so I don't know that a distiller can really design the process for high proof, short of cherry picking barrels by proof vs. flavor, which sounds like a terrible way to make whiskey.”

If there is demand for a particular style of whiskey and there’s money to be made, you can be sure some company will fulfill that role. Barrell Craft Spirits made it their business model to exclusively release barrel proof products. It’s likely only a matter of time before a new boutique company is created that solely releases 140+ proof whiskey.

The big heat

‍If you think back to those hard boiled detective movies of yesteryear and the characters pouring a stiff glass of whiskey neat, taking a swig and showing no signs of discomfort. These hardened detectives could drink whiskey as if it was water (and it most certainly was on set, but nevertheless). Drinking whiskey like that seemed unthinkable, as if it was something you only saw in the movies. But like many enthusiasts, 80 proof whiskey gave way to 100 proof whiskey and soon barrel proof whiskey was conquered much like its lower proof comrades were. It’s funny to look back and realize those detectives in their movie realities were most likely drinking 80 proof whiskey. It would be interesting to see how hardened these detectives really were after taking a sip of a Hazmat whiskey. Could they really handle the big heat?