From the golden age of the cocktail in the 19th century to its contemporary revival in the 1990s and early aughts, there have always been a few hallmarks that defined the cocktail bar. A major common denominator has, for a long time, been a backbar stocked with curated bottles of spirits and liqueurs from which bartenders would dance back and forth, pulling, pouring and mixing spirits. The backbar has long served as a visual representation of the scope of a bar. For the most part, beyond simple syrups, juices and other modifiers, the bottles fixed on these shelves were all that bartenders had to craft their library of memorized recipes.
But over the past decade, cocktails have evolved to become more conceptual, requiring endless hours of intricate prep. Consequently, the backbar has become more minimalist—in some cases disappearing altogether. More and more often, bartenders are taking the drink-making behind the scenes, using lab-grade technology to bring high-concept cocktails to life. At the center of this new breed of bar is one piece of equipment in particular: the rotovap, a vacuum distiller used to create sophisticated, flavor-packed cocktails. And it’s popping up in bars around the world.
At Crossroads Bar in London, the Girovap, one brand of vacuum distiller, is front and center in the otherwise minimalist backbar, offering guests the chance to watch the distiller work its magic in real time. At A Bar with Shapes For a Name, also in London, owner Remy Savage stages the bar’s Büchi Rotavapor adjacent to the bartenders’ work station in the upstairs lab, a feature visible through an internal window. And at Sips in Barcelona, guests have a front-row view of the bar’s rotovap resting on the backbar.
Vacuum distillation may be most prevalent in cocktail bars today, but it’s been around for nearly two decades, first gaining traction in London in the early aughts. In 2014, Dave Arnold, who’d also been experimenting with vacuum distillation in the United States, published his technique-driven magnum opus Liquid Intelligence and further nudged the rotary evaporator into the limelight. Since then, the vacuum distiller has proliferated at bars around the world.
How it works, in essence: A vacuum pump lowers the atmospheric pressure within a liquid sample’s environment—typically housed in a bulbous flask or sealed vessel—which lowers the solution’s boiling point. By lowering the boiling point, bartenders can distill an infused spirit or solution gently, with minimal oxidation and without the excessive heat that occurs in traditional distillation, yielding a more flavor-packed liquid.
At Himkok in Oslo, Norway, head of flavor R&D Paul Aguilar is one of the many bartenders harnessing the equipment to create boundary-pushing cocktails. He describes the rotovap as being able “to capture the essence of various ingredients and enhance the flavor profile of cocktails in a cleaner format.”
For the bar’s Beetroot Martini, Aguilar creates a clear beetroot distillate composed of vodka, beetroot juice and chile through vacuum distillation. The resulting infusion is clear and light-bodied—an aesthetic fit for a Martini—despite containing layers of flavor. The process also removes the capsaicin compound present in the pepper, eliminating the mouth-tingling effect while still capturing the chile’s complex flavor. It’s an ingredient that simply wouldn’t be possible without the rotary evaporator.
Alex Francis, bar director of Paris’ Little Red Door, started using a rotovap in 2020 for the bar’s “Don’t Judge A Door By Its Color” menu, which “explored flavor and sensation” by isolating or stripping away key flavors from otherwise recognizable ingredients. The list included drinks with descriptions such as “Coffee Without Bitter” and “Honey Without Sweet.”
For the “Chilli Without Spicy,” Francis and his team created a distillate of Carolina Reaper chiles, which accentuated the aromatic profile of the dry vermouth and bell pepper cordial that it was mixed with. Similar to Aguilar’s Beetroot Martini, the distillate expressed a sharp pepper note without any of the capsaicin. For the drink, and the entire menu, the rotovap completely transformed the recipe development process; not only was it a tool for drink-making, it was a springboard that enabled creative ideas.
While distillation may call alcoholic ingredients to mind, some bars are using rotovap technology to make nonalcoholic cocktails. At two-Michelin-starred Kitchen Table in London, bar manager Mikolaj Kwasniewski creates various hydrosols—water-based, herbal distillates—to use as the base ingredients for the restaurant’s contemplative “soft pairing” menu, a zero-proof option that has surged in popularity alongside sober curiosity.
Kwasniewski says that distillation helps the restaurant preserve seasonal ingredients and isolate individual flavors, which is especially important when designing drinks that pair with food without overshadowing the dish. To accompany Kitchen Table’s rotating array of fish courses, he developed an oyster leaf hydrosol by blending the briny leaves with water and distilling the solution via a rotovap. He then blended the distillate with a lemon cordial and water before force-carbonating it all to serve as a salty-citrusy highball fit to accompany a fish course.
Meanwhile, in the United States, creating distilled alcoholic products at a bar is still illegal, but the technique is being embraced as a tool to enable cutting-edge nonalcoholic programs. At Shawnee, Kansas’ brand-new cocktail bar, Wild Child, which opened in July, owner Jay Sanders invested in a Girovap to strip the alcohol away from spirits. “Oftentimes, the nonalcoholic spirit that is commercially available is around the same price as the alcoholic counterpart,” says Sanders. So he decided to invest in a distiller to make his own nonalcoholic “spirits” for the drinks list.
For Wild Child’s alcohol-free Negroni, Sanders combines equal parts gin, sweet vermouth and Campari and uses the rotovap to separate the alcohol from the solution. He replaces the lost volume of alcohol with a gin-flavored hydrosol made from botanicals that commonly appear in the spirit, like juniper. It’s “the closest approximation to the true Negroni” that the bar has been able to come up with, Sanders says.
Of course, purchasing a costly vacuum distiller doesn’t automatically elevate a bar into world-class territory, nor does it make sense for every bar’s cocktail program. The technology requires a certain level of expertise to operate and develop creative drink concepts. In that sense, the rotovap has become like any other tool in a bartender’s arsenal. “None of the equipment in a lab will make your ideas better,” says Francis, but with practice, “they will allow you to express them in the best possible way.”