The craft cocktail resurgence of the 2000s can be boiled down to one major concept: caring about the process of making a single drink. In the extreme, this means doing things like stirring a Whiskey Highball exactly 13 times or carving ice to create something that is both functional and sculptural. Watching a bartender lovingly and thoughtfully create a cocktail is part of that drink’s appeal, and that might be the reason some people find cocktails on draft to be a turnoff and write curmudgeonly takes like, “like it or not, draft cocktails have graduated from passing trend to inevitable staple.” But draft cocktails require just as much craft as other cocktails, if not more. They are much more complicated than just scaling up from a single drink to a pitcher’s worth.
The gas needed to pressurize the cocktail kegs can produce off flavors if you aren’t practiced in the process. And because the kegs can take weeks to finish, bars and restaurants have been limited in what they can make. Fresh citrus has generally been ruled out as an ingredient because it separates out from the other ingredients when it sits for long periods of time. That eliminates wide swaths of drinks. But there is an unexpected way around that problem, and it involves the dairy aisle.
Clayton Rollison, the chef and owner of Lucky Rooster in Hilton Head, South Carolina, wanted his bar team to work up a draft cocktail program for the same reason many places have in the last several years: It was an efficient way to get drinks out the door. He had a friend who convinced him that “[draft cocktails were] awesome—you can do a 100 percent spirit cocktail that won’t take forever to stir.” But, because of the limitations around juices, those 100 percent spirit cocktails were all that there were. The category of draft cocktails was dominated by Manhattans and Negronis.
It bothered Rollison that there wasn’t a good way to use citrus on tap. Fortunately, he’d already been doing some research on milk-washed cocktails. He says, “In the 1600s they would make these classic punch recipes with arak and rum and citrus and you’d end up with it sitting around for a couple days. [So] how do you store it? They’d mix the whole drink together and pour the mixed cocktail into whole milk.” If you’ve never tried it before, this is the point where you probably say, “Ew, gross.” So first we better explain milk washing. To “milk wash” a cocktail you add milk to it, which forces it to curdle. Then, you strain out the curds, through something like cheesecloth (or a pillowcase if you’re old school), leaving you with a relatively clear drink. That’s why you may also hear this process referred to as clarifying a drink.
According to Rollison, milk washing accomplishes two things: It pulls the impurities out of the spirit and strips the proteins out of any citrus. With the proteins stripped out, the citrus no longer separates from the rest of the drink, finally making the cocktail a candidate to be put on tap.
Armed with that information, Paul Rabe, the head bartender at Lucky Rooster, tried a simple experiment: He made a keg of Whiskey Sour (with cheap bourbon—they didn’t know how this was going to work out), added milk, and double strained it through cheesecloth and a coffee filter. Then, he pressurized it and stuck it in the restaurant’s walk-in cooler. Four months later, after sitting in what Rollison describes as “the absolute worst conditions it could be in,” the drink still tasted like it did on day one.
The whole process took the Lucky Rooster team about a year to perfect, but now, a couple years in, Rabe regularly keeps a milk washed cocktail on draft—right now, it’s the Clear Skies, a take on a Paper Plane made with Four Roses bourbon, Amaro Nonino, Aperol, lemon juice and whey.
It’s not clear whether or not how widespread this technique is—Rollison said he doesn’t know about other places using it right now. But the next time you’re out and see a menu of cocktails on tap, check if they too have figured out the secret that does a body good.