Whether you call them cask strength or barrel proof, these American whiskies offer up some serious heat. Uncut, unfiltered and stacked at a much higher proof than average commercial whiskies, these beautiful brown spirits taste as they do coming straight out of the barrels, hence barrel proof. To get a better idea of what sets each apart, we tasted through each of these with Egor Polonskiy, beverage director at Chicago’s Untitled Supper Club, which has more than 600 American whiskies in its collection. And yes, it was all done in the name of research, naturally.

So why cask strength, and why now? The higher-proof whiskies paint a much truer picture of what the distillate is all about, Polonskiy said. As bourbon grew in popularity over the last five or so years, more people experimented with a wider variety, allowing their palates to adjust and handle higher proof. “The more you drink, the finer they taste,” he added. “There’s no wrong way to drink, but the high-proof whiskies do best with just a touch of water to soften it up and round those edges.” Not to mention mellowing out the heat. Don’t forget: These fire-fueled cask-strength whiskies regularly run north of 110 proof and don’t come with an extinguisher. You’ve been warned… or encouraged.

Angel’s Envy Cask Strength

Aged in port wine barrels like its regular bourbons, this yearly changing expression offers nice cinnamon, caramel, dried fig and vanilla notes with a clean finish that’s smoothed out through the port finishing. The 2016, with only 8,000 bottles on the market, clocks in at a whopping 124.6 proof — the highest ever from this Louisville distillery. ($169.99, angelsenvy.com)

E.H. Taylor Barrel Proof

If you’re a fan of the Colonel E.H. Taylor Small Batch bourbon, finding the Barrel Proof will definitely bring a smile to your face. It ranges between 127.2 and 134.5 proof (the one we tasted landed at the high end) and has a beautiful caramel color. The nose offers a mix of caramel, vanilla and cherry bark and, despite the high proof, it’s surprisingly smooth in the mouth with caramel, spice, leather and fruit notes. ($69.99, buffalotracedistillery.com)

Redemption Aged Barrel Proof High Rye Bourbon

This nine-year-old bourbon contains more than 25 percent rye in its mash bill, making it a high-rye spirit. It’s 109.2 proof and is even spicier than some other cask-strength bourbons due to the high rye content, which brings out the heat, but also offers baking spice, cinnamon, and bitter orange notes. ($99.99, redemptionwhiskey.com)

Jefferson’s Ocean Cask Strength Bourbon

Talk about going the distance for your craft: Jefferson’s Ocean is produced in small batches and then the barrels are set to sea to age, often crossing the equator three to four times, visiting five continents and more than 30 ports during the journey. Briny sea salt air, temperature fluctuations, and the gentle rocking of the ocean all influence the bourbon as it ages. Each batch takes on different characteristics, and the “Voyage No. 7” that we tasted offers sweet vanilla and cotton candy notes on the nose with heavy deep wood characteristics that turn into sweetness and toasted brown sugar in the mouth. At 112 proof, this is definitely a very special selection. [$69.99, jeffersonsbourbon.com)

Maker’s Mark Cask Strength

Imagine having your favorite Maker’s Mark amped up with all its flavors heightened. That’s what you get with the cask strength, ranging between 108 and 114 proof depending on the batch. “This is like regular Maker’s Mark but on steroids,” Polonskiy said. The high-wheated bourbon (corn, malted barley, and wheat make up the mash bill) we tasted landed at 111.4 proof and offers very concentrated flavors. It starts out with pine and evergreen on the nose and leads to a great mix of vanilla, nutmeg, cinnamon, and a touch of chocolate and spice. ($59.99, Makersmark.com)

Barrell Bourbon

What’s fun about Barrell Bourbon is it sources barrels from distilleries they really like and then their master blender blends the bourbon to his liking — and they’re all cask strength and limited release. So once they’re gone, they’re gone, but they’ll keep making more. Each generally ranges between 120 to 125 proof, has a unique flavor profile and all run pretty hot. Look for the New Year 2017, which blends a variety of bourbons aged five to 13 years and comes in under the norm at 117 proof. We didn’t get the chance to taste this new offering, but love Barrell Bourbon’s description, “Crushed stone and broiled fruit give way to wet saddle leather and generous dollops of heavy sweet cream oozing over cast iron baked cornbread.” Sounds tasty. ($84.99, barrellbourbon.com)

Bulleit Bourbon Frontier Whiskey Barrel Strength

Even though Bulleit’s limited-bottling cask strength version lands at 119.4 (depending on the batch will be between 118 to 125 proof) and initially shows high alcohol on the nose, it quickly rounds out to some nuttiness and charred oak. It’s surprisingly smooth in the mouth, offering hints of dark cherry, baking spice and maple. It has a nice long finish and would go perfectly in a glass with a couple of cubes while you chill in front of a fire. ($49.99, bulleit.com)

Michter’s Barrel Strength Kentucky Straight Rye

Looking for a special gift for a rye lover? This limited release often hits between 108 to 110.8 proof, but the one we tasted soared at 114.6. Due to the high rye content, you get an initial alcohol burn and, oddly, the nose gives off a bit of rotted wood. Fortunately that dissipates into more pleasant butterscotch. The palate is where it gets fun. It has a bit of a cream soda essence with toasted marshmallow, sarsaparilla and sweet vanilla with the oak coming through quite nicely. ($75, michters.com)

Jack Daniels Single Barrel Barrel Proof

Say that name fast 10 times: Jack Daniel’s Single Barrel Barrel Proof. OK, now do it after drinking a glass of this varying proof (it can range from 125 to 140 proof, and we’ve tasted it at 129 and 134.6) and say it again. Thankfully it’s easier to drink than it may be to say. Whatever level you find it, it’s generally all really good. The latest we tried smelled like fragrant bubble gum and was really hot at first taste. It coats your palate and lingers in that good, mellow way you want it to. Its long finish offers some herbaceousness and earthiness following hints of vanilla and toasted oak. ($65, JackDaniels.com)

Stagg Jr.

From George T. Stagg, this uncut version clocks in between 128.7 and 134.4 proof, depending on when it was bottled. This small-batch bourbon ages for nearly 10 years and when it’s ready for bottling, it definitely comes off hot. The bottle we tasted hit 132.5 proof and was so hot, it induced hiccups. You’ll pick up a mix of molasses and chocolate with a long finish with maple and caramel similar to the color of the bourbon itself. ($49.99, buffalotracedistillery.com)

Wild Turkey Rare Breed

You may not think of Wild Turkey as premium bourbon, but father-and-son distillers Jimmy and Eddie Russell would beg to differ, especially when it comes to their Rare Breed, a 112.8 proof barrel proof whiskey that “is as good as cask proof gets,” according to Polonskiy. It’s a blend of eight- to 12-year-old bourbons that hit that sweet spot of where bourbon should be before getting bottled as cask proof, where it’s not too oaky from the older bourbons or too edgy from the younger ones. It has a bold nose leading to a well-balanced, nutty palate. This is a barrel proof you can drink neat — it doesn’t even need water or ice. “Just drink it,” Polonskiy added. ($42.99, wildturkeybourbon.com)

Boondocks American Whiskey Cask Strength

This one is a bit of a mystery in that we know the whiskey, comprising corn, rye and malt, is aged for 11 years in Kentucky, but its origins are unknown. Master distiller Dave Scheurich, an industry veteran who was the distiller at Woodford Reserve, also crafts this 127-proof offering and its sister, a 95-proof whiskey. While its warm, welcoming color may look tame, the heat on this made me hiccup at first sip before revealing its pleasant caramel, butterscotch and vanilla notes. ($59.99, boondockswhiskey.com)