The highball is the epitome of simplicity. It weds just two ingredients—spirit and carbonated water—into an amalgam that adds depth and dimension to each component. It’s a format that’s delicious at every level of complexity. Even dive bar Gin & Tonics or Scotch and sodas are irresistible, yet drinks like Orlando Franklin McCray’s White Negroni Highball and Julia Momosé’s Highball prove that the format can be stretched to the deepest realms of creativity. But what if I were to tell you that even in its most pared-down construction, the highball is never just two ingredients? In order to achieve the pinnacle of the format, we have to leave the safety and comfort of bottled sodas behind and embrace carbonation as its own ingredient. Enter force carbonation.
[aside headline="Building Your Carbonation Rig"]
Fill Your CO2 Tank
You can swap an empty tank for a full tank of the same size or get your tank filled at a local welding supply store. Home brew shops or sporting goods stores that sell paintball supplies also can fill empty tanks.
Attach the regulator to the tank. Get it hand-tight, then about a half-turn tighter with a wrench. Make it tight enough to avoid leaks, but not too tight—that can damage the gasket. If you still have leakage, coat the threads in plumber’s tape. Attach the ball lock system to the regulator. The former will come with screw clamps to attach the tubing to the regulator. These work fine, but can be replaced with Oetiker clamps for a sturdier, more permanent connection.
Dial in the Pressure
Screw a carbonation cap onto a seltzer bottle and connect it to the ball lock system—this takes more pressure than you think, so push hard. The bottle will inflate immediately and should be very firm. Adjust the pressure with the knob on the front of the regulator to your desired level.
Force carbonation is the process of pressurizing a liquid with carbon dioxide gas (CO2) so that it dissolves in the liquid, making it effervescent. It’s how bubbles end up in every commercial soda. And it’s the same process behind many at-home carbonation gadgets, like the SodaStream. The benefit of applying this technique to a complete cocktail is obvious: If every component of a drink, including spirits and modifiers, is carbonated—rather than a still spirit topped with soda—you will have better, longer-lasting bubbles.
But, as all SodaStream owners know, putting anything other than water in the unit will immediately void the warranty and will often result in a sticky explosion. Even if that weren’t the case, the device still lacks the ability to control the pressure at which you carbonate, so there is no flexibility in the texture of the bubbles and it’s nearly impossible to slowly vent pressure to mitigate foaming. It’s possible to get good carbonation using an iSi siphon, but CO2 chargers are expensive and single-use, so they generate a lot of waste.
To get the best results, you’ll want to build a carbonation rig, which sounds and looks much more intimidating than it is. You’ll need a 10- or 20-pound CO2 tank (anything bigger is overkill for at-home use), a regulator to control the pressure, a ball lock system with at least 5 feet of hose, carbonator caps and some 1-liter plastic seltzer bottles—any brand will do. The whole rig will cost less than $200 and will eventually save you money, either in SodaStream gas refills or in cases of club soda, if you are a full-time bubble fiend like me.
From my years working at Booker and Dax and Existing Conditions, I’ve accumulated all the tips and tricks that aren’t exactly intuitive; it can be tough to troubleshoot when working with this type of carbonation rig. Here are some things to focus on when you get started carbonating.
Aim to carbonate your cocktails at 45 pounds per square inch (PSI, the imperial unit of measurement for gas pressure) and your water at 60 PSI. Experiment with other numbers, but this is the pressure where we found cocktails had a silky, Champagne-like texture and water is just ripping carbonated.
Make sure whatever you want to add bubbles to is as close to freezing as possible, since CO2 dissolves better in cold liquids.
Only fill up the bottle you’re carbonating in 75 percent of the way. You’ll have to shake the bottle when it’s attached to the CO2 tank, and leaving headspace gives you room to agitate the CO2 into the solution. Squeeze the remaining ambient air from the bottle before tightening the carbonator cap, so that the liquid will be in a pure CO2 environment once the bottle is attached to the rig.
Shake It Hard
Once the bottle is attached to the rig, keep it attached and shake it hard for about the same amount of time you would shake a cocktail. Keep the bottle upright; if you turn it on its side or upside-down, liquid could drain into the tubing and you could cross-contaminate drink batches or end up with a sticky mess.
Carbonate Three Times
When starting from a completely flat liquid, always carbonate three times to make sure the maximum quantity of CO2 is dissolved in the solution. Carbonate once, allow the bottle to sit for at least one minute, then open slowly to mitigate foaming. Repeat this process two more times. If the liquid is already carbonated, just give it a quick charge with CO2 every time you open the bottle to make sure the bubbles stay pristine.
When experimenting with carbonated drinks, remember that you will never be shaking or stirring it with ice, so add all the dilution the drink needs in the form of water, syrups and clarified juices. (Anything cloudy will foam like crazy and won’t hold on to carbonation as well, so try to avoid those ingredients.) For every two ounces of full-proof spirit that goes in, add around four ounces of dilution. Start there and adjust to your personal taste.
When using wine-based ingredients or lower-proof modifiers, you can cut the dilution ratio from 2:1 down to 1:1, like I did in the Step Back, a mixture of Sfumato amaro, Caperitif and dry vermouth. Ingredients like vermouth, amaro, sherry and other fortified wines are useful tools to play with in the carbonated format because they provide bitter and complex flavors without calling on fresh citrus or other perishable fruit. Of course, fruit flavors are still fair game, albeit in clarified form. Once you’re versed in clarification techniques, try out something tropical like the Cruise to Nowhere, a carbonated mixture of clarified guava and lime juices, blanc vermouth, pineapple rum and aquavit.
Since they can be batched ahead of time and served from the bottles you make them in, carbonated cocktails are ideal for parties. Any extra can be kept in the freezer for long-term storage and thawed as needed. If you plan on making and storing more than you can use in a day, leave out the most perishable ingredients, like clarified lime, and add it directly to the glass when you serve the drink. This allows for 95 percent of the carbonation results without having to worry about tossing a whole batch because of lime juice that’s gone dull.
Try carbonating at your next party or on your next cocktail menu. Your guests—and your highballs—will thank you.