In the seminal and borderline terrifying 1971 children’s movie “Willy Wonka and the Chocolate Factory,” the signature candy created by Gene Wilder’s eccentric titular character is the Everlasting Gobstopper. The jawbreaker-like spherical sweet constantly changes color and flavor when enjoyed, but it never disappears. It’s allegedly delicious.

Infinity whiskeys may best be described as the adult form of the Everlasting Gobstopper. Unlike their fictitious candy counterpart, they can exist in real life. Similar to the Gobstopper, they can be definitively tasty. They’re created by blending whiskeys together in a single unique vessel; whatever is poured out gets replenished by new and different juice, thus creating an ever-evolving flavor profile. It is a relatively new phenomenon in the spirits world — first hitting the collective consciousness of whiskey geeks around 2012 or so. It has since developed a cult-like following among professional bartenders and hardcore whiskey aficionados alike. There’s good reason for this: When done properly, infinity bottles can create a unique flavor profile that exists temporarily in an exact moment in time and enjoyed by only a few people lucky enough to be in its presence, like a color-splashed sunset unbound by photographic proof.

The beauty of an infinite whiskey is that its construction can range from simple to complex, depending on how much time, effort, and resources an individual can access. For the home drinker prone to gathering their fair share of bottles, just the act of carefully combining whiskey dribs and drabs into a 750-milliliter bottle can elicit happy intrigue. This is something retired-lawyer-turned-whiskey-collector David Stewart certainly understands. He currently has a quartet of infinity bottles working in his Los Angeles home, forged from the collection of nearly 100 bottles of brown juice he keeps in his homemade whiskey closet. “I have a high-end Irish, a budget Irish, a good Scotch, an American single malt, and a good bourbon bottle,” he says. “I do it for fun, but I also do it for nostalgia. I thought it would be a sentimental way to always have a bit of my favorites around, even after they’re gone.”

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Pros who create infinity whiskies can occasionally transform the concept into a project of esoteric ambition that can practically make a whiskey geek’s brain spontaneously combust. The infinity whiskey created at London’s Black Rock particularly pushes the idea close to its edge. Theirs is a constantly changing mélange nestled within an oak stave-lined trough cut into the center of a massive, bisected tree. Taps protrude from the tree’s edge, granting those sitting around the lengthy table-like hunk of wood access to the juice. According to Black Rock co-owner Tristan Stephenson, the liquid’s profile is constantly adjusted to guide it toward a specific flavor profile or to match the mood of a certain season. The uniqueness of a constantly changing whiskey served from the inside of a tree makes it an essential item to order, regardless of what it may taste like. “Most people will drink from the tree the first time they visit,” Stephenson says. “When we know it’s their first time here, we’ll usually ask them, ‘Why are you looking at the menu? Just give it a try.’”

For adventurous imbibers, the urge to try a singular whiskey featuring fleeting, fluctuating flavors can feel like an irresistible one. If you fall into that class, you may be inspired to start your own infinity bottle at home. Doing so can be great fun, but it can also be educational. “Everyone should try to make their own infinity whiskey to get a full appreciation of what’s involved in the process of making whiskey,” says Dave Sweet, founder and president of Barrel and Bottle and partner of 50 State Blend. “It can also help people learn about their own palate, which can help them gain an even deeper appreciation of the whiskey they like.”

How to Make Your Own Infinity Whiskey

Building an infinity whiskey bottle at home doesn’t require an elaborate setup, nor does it necessarily demand a wide collection of juice at home. Technically, all you need to get going is a couple different whiskies and an empty bottle. But these basic requirements don’t make building the juice a free-for-all, either. VinePair turned to a few infinity whiskey veterans to figure out their best practices for starting and maintaining this unique form of liquid deliciousness.

Step 1: Take the Right Approach

There’s only one goal you should have in mind when you’re making an infinity whiskey before you start the process — make the best-tasting whiskey possible. As such, building an infinity whiskey should never be approached as a novelty, even though building one can be a fun project. “You’re going to want to drink what you make at one point, so you have to strive to make it good and drinkable,” says Brenden Burley, bar manager at Craft House in Dana Point, Calif. “You don’t want it to just be a bunch of bottle leftovers. If you do that, you’re essentially recreating a dump bucket.”

Step 2: Select and Prep the Right Bottle

When you’re ready to build your infinity whiskey, you should always start off with an empty bottle that’s thoroughly cleaned with soap and water. Don’t cheat by starting off with a whiskey that’s already in its original bottle. “If you do that, your infinity whiskey is always going to taste and smell like that initial whiskey because it’s been living in its bottle for so long,” Burley says.

Bottle size can matter when you’re selecting a vessel. This decision comes down to how frequently you’re going to dip into the elixir. “You don’t want to allow your bottle to go empty,” Stephenson says. “If you plan on drinking it a lot, a bigger bottle will better your chance of keeping your whiskey going.”

Once your bottle is filled, it’s important to keep it in an environment that’s shielded from excessive heat or light — failure to do so can cause your juice to lose flavor and alcohol content. You should also make sure the cap of whatever bottle you use consistently fits tightly. “A seal that isn’t tight may let in air,” says Sweet. “This could soften the whiskey a bit, which may cause it to lose some of that bite you want.”

Step 3: Pick Your Base

While an infinity whiskey’s flavors will change with each addition, the first whiskey you select for your project sets its tone. This opening spirit doesn’t have to be something expensive or grandiose. Kicking things off with a 1.5- to 2-ounce dram from an everyday sipper will do quite nicely, provided the sipper is one that you normally enjoy. “Don’t start off with something you think is crap,” Stephenson warns. “If you do, you’re always going to be chasing your tail, so to speak.”

Step 4: Pick a Whiskey to Add

You’ll want to fill your infinity bottle roughly halfway with a few drams of other spirits after you’ve established the base. However, there isn’t a specific time when these juices should be added. Whiskies start mingling the moment they come in contact with each other, so you can add extra whenever the mood strikes. “I add something every time I open a bottle,” Stewart says. “If the infinity bottle gets too close to the fill line, I’ll have a pour or two to lighten it up.”

Picking the right whiskey to add takes a little more conscious thought. For instance, a higher-proof whiskey will be tougher to introduce because it could potentially overpower the blend, particularly if you add a larger amount to the mix. Introducing different whiskey types into an infinity bottle, such as adding an American single malt into a bourbon-heavy blend, can also be a tricky task. “If you’re mixing different genres, prepare yourself for some ups and downs,” Sweet says. “If you’re not careful, you’ll have more downs than ups.”

Step 5: Taste Test

When you’re making an infinity whiskey, you don’t necessarily have to pour something into the bottle and hope for the best. If you’re unsure about how a new spirit may react to your homemade juice, blend the two in a small glass or a beaker first and give it a taste (just make sure you scale down the respective ratios). If you seal this vessel tightly, you can keep coming back to the mixture and keep note on how its taste evolves over a few days. If you like what you taste, then proceed with the addition.

If you don’t experiment, and the new whiskey you just added takes the spirit in an undesirable direction, don’t fret. Some whiskeys take time to play nice with each other; giving them a few days to settle together can yield better results. If the whiskey’s still too harsh for your taste after this resting period, you don’t necessarily have to try and course-correct it with another spirit. “Don’t be afraid to add some water if you need to,” Sweet says. “Water will help you round out your blend. It doesn’t have to be a lot. Even an eyedropper’s worth may do the trick.”

Step 6: Enjoy the Fruits of Your Labor

When you’ve gotten your infinity whiskey to a point that puts you in a happy place, pour a dram and enjoy its results. Share it with a friend if you’re feeling generous. Reflect on the journey you took with the bottle, and smile at all of the twists and turns you had along the way. Just don’t drink it all. Remember, it’s not called a finite whiskey.