Scotland's Panda & Sons Uses Freezing Techniques To Make Drinks Of The Future

Edinburgh's Panda & Sons may look like a red-painted barbershop from the outside, advertising 25-cent haircuts and shaves, yet a loitering crowd and a doorman holding a clipboard are hints that appearances can be deceptive. Panda & Sons is, in fact, a local institution — a trendy speakeasy where guests are led into tucked-away chambers that house sumptuous seating, candlelit tables, and a lively cocktail bar where the drinks list is divided into chapters. Instead of a story, however, Panda & Sons offers Transcend, a cocktail menu devoted to freezing techniques devised by the Panda & Sons team through years of practice.

For owner Iain McPherson, participating in two courses on the science of ice cream (including one at Bologna's Carpigiani Gelato University) led to the exploration of Italian gelato making and, eventually, inventing his own liquor-infused ice cream. His quest to experiment with frozen ingredients didn't ease, and in time, freezing processes and sub-zero methods made their way behind his bar. "I've always been fascinated by the flavors that freezing creates," McPherson told Punch.

In 2019, McPherson and the Panda & Sons crew pioneered their "switching" process, in which ultra-low temperature freezers are used to remove water from spirits before an alternative liquid is added. "Once the spirit is partially frozen, we take out a large quantity of the frozen water and switch it with another flavor and, in some cases, textured liquid (like coconut milk)," McPherson explains in Class Bar Magazine. 

Spirits are poured into insulated cool boxes in the bar's Brain Melting Society lab, with lids removed to encourage directional freezing. They're placed into special freezers with temperatures set very low so that the liquid is separated into frozen water and a higher-proof spirit. At this stage, the frozen water — or ice — is removed using a sieve and switched with another ingredient like orange juice or clarified pink grapefruit juice. The method intensifies the alcohol flavor and gives a richer mouthfeel. This extra-strong alcohol is rediluted with whatever is added in. 

"I started thinking about Legos," McPherson explained to Punch. "How you can swap heads or legs, switch them around, and create a whole new thing." The switching method is used for Panda & Sons' Daiquiri cocktail, in which the water content of Bacardi is replaced with Thai coconut milk. The bar's Cosmos is made similarly, with the water in vodka replaced with freeze-concentrated cranberry juice. Gin, vodka, Scotch, and rum have all been switched at Panda & Sons. And that's only Chapter 1.

The rest of the menu at Panda & Sons showcases other techniques that rely on sub-zero temperatures. Each chapter serves as an umbrella of a specific process so customers can experience and compare how drinks vary depending on the method used. The second section — Chapter 2 — is the result of the team's research into sous vide and chamber vacuum processes. Named Sous Pression, Panda & Sons compares the process to a burst frozen water pipe. They say the concentrated force of the process extracts flavor from produce, which bursts out and fuses with other ingredients. Essentially, cocktail ingredients are batched, frozen, fused, and defrosted before being slid across the bar.

"Imagine if sous vide was created in an alternative reality," McPherson writes in Drinks International. "During the freezing process, the molecules separate and combine again once defrosted, thus marrying the flavor molecules together." This is how Panda & Son's Sability cocktail is made, with gin, fino sherry, vermouth, Sable grape, and Maraschino liqueur offering a smooth, silky mouthfeel. The combined liquids and grapes are forced together during the freezing process, resulting in a wallop of flavor poured into a glass. Yet this flavor-intensifying technique doesn't necessarily need to be reserved for batching complete recipes, McPherson explains, as infusions and pre-diluted cocktails can also be created in this way.

The third chapter of Panda & Sons drinks is focused on freeze drying, a more commonly known technique. Produce is placed on trays and fast frozen, then added to a freeze dryer to be stored. Freeze-drying helps deliver the flavors of products in more concentrated servings. "Back in the day, freeze-drying was limited to astronauts," McPherson writes in Drinks International. "Freeze drying in our eyes is the more sophisticated cousin to the dehydrator. It also helps us minimize waste and break down the limited availability of seasonal products."

Though freeze-drying was initially used for cocktail garnishes and crushed powder, which decorated glassware, in the case of Panda & Sons' Seville Negroni, mandarins are freeze-dried and vacuum-blended with gin. "By using freeze-dried produce we can still infuse its fresh flavor, but without the dilution a fresh mandarin would bring to the drink," McPherson explains. He is a man who is extremely keen to eradicate flavorless water in his drinks.

The final chapter of Panda & Sons' sub-zero manifesto showcases cryo concentration, a long-practiced technique that inspired the team to tinker with temperatures. McPherson admits to researching this process heavily and employing the technique of freeze ripening, a way of boosting the flavor and sugar levels of produce that hasn't quite yet reached its prime.

Also known as freeze concentration or freeze distillation, the water present in a given liquid is intentionally frozen to the ratio of the other elements present. Reducing the dilution of juice or spirits lowers the overall freezing point of a liquid, which helps the bartenders at Panda & Sons make colder drinks with flavors that might otherwise be missed. The process has been used to create amaros from vermouths, and to transform gin, peach, jasmine, absinthe, and champagne into Girvana, a cocktail that undergoes a multi-step freezing process and culminates in a drink with notes of a ripe, juicy peach.

Despite the use of frigid temperatures and ingredients, settling into Panda & Sons is anything but a chilly experience. While the innovative drink menu might appear to be something out of the future, the recipes, tastes, bartenders, and ambiance of the speakeasy are firmly rooted in the fun-loving present.