Distilling is an ancient art. Records date it to at least the 13th century, but it probably existed much earlier. Basic distillation doesn’t require fancy equipment. Simply boil wine in a pot, partially cover it with a lid and collect the condensate. That’s distillation.
Of course, with the advent of pot stills (alembics) and then column stills, things got fancier — and with automation, fancier yet. Nevertheless, the process stayed pretty much the same: Heat an alcohol-containing liquid (something that’s been fermented) until it vaporizes and, since alcohol boils at a much lower temperature than water, you can collect its vapor and re-condense it to create a more pure alcoholic solution.
But lately that ancient technique has undergone some major revisions. Sure, the outcome is the same — the separation of alcohol from solution — but the mechanics are very different. Perhaps the most exciting development? New-wave distillers have been able to get rid of the heat required in the process. And that may be a game-changer.
Trading heat for a vacuum
For this new heat-free method, technologically oriented distillers use a vacuum to bring down the air pressure of the distillation chamber. Lower air pressure means that the volatile compounds and alcohol vaporize at lower temperatures, requiring less cooking. Consider gin: It’s made by using a slew of botanicals — juniper, obviously, as well as things like star anise, citrus peel, orris root, coriander, cassia bark, angelica and more. Until recently, the common factor in all gins distilled was that these botanicals were cooked or steamed in a still. And we know how cooking can change flavor: Think fresh peaches versus boiled or baked.
Dave Arnold handles technology for the French Culinary Institute in New York and has played around a lot with vacuum (also called rotary; read his discussion of this technology here) distillation. He discusses its advantages this way: “Infusions are the easiest. They’re extremely popular these days. Take a high-proof spirit and let it sit with an ingredient. The vacuum distiller really accelerates the infusion time, taking it from days and weeks to minutes and hours.” And, he says, it helps distillers manage their product more carefully. “Using an alembic, your level of control over the output is nothing compared to what you can get with a properly equipped rotary evaporator,” he says.
Arnold cites three advantages of vacuum distillation over the regular process. “One, low-temperature distillation means there’s no heat-related degradation of the product being distilled. Two, I can get almost complete recovery of my product in terms of flavor, unlike a normal still. Three, the vacuum tends to separate out the liquor better, so I can get a much higher proof spirit on my initial run.”
This has been a successful strategy for Arnold and the few using it. Getting rid of the extreme heat to pull flavors out is a huge advantage. Yet even in Arnold’s lab, it was still necessary to heat up to at least 115 degrees to vaporize the essential materials. But recently, Bacardi hit on the vacuum technology that allowed them to distill at much cooler temperatures. The first example of this is Oxley gin, which was slowly rolled out last fall. It’s distilled at about minus-5 degrees Celsius, or 23 Fahrenheit. The resulting gin is the first that tastes not of cooked botanicals, but of fresh citrus peels.
Vacuum-distilled spirits have unique flavor
Is Oxley a better gin? Well, I had no problem with the gins already available, but it certainly is different. It offers a vibrant, clean and fresh set of aromas that are noticeably bright and distinct. The juniper has a mellow, inviting aroma as opposed to the harsh and aggressive turn it can take in some gins. A peppery hit of coriander is bright and distinct. My only quibble with the gin is that it seems to be a little reserved in terms of its overall aromatic profile. It kept its overall volume low so as not to offend anyone. Tasted against other gins, I felt it was lovely, but sometimes lacked the sheer exuberance of other products. I’d love to see this new cold distillation with the gloves taken off.
There are now other vacuum-distilled products available, though none (as far as I know) are made with the sub-zero technology pioneered by Bacardi. Dallas-based Delos vodka uses a vacuum still, but still boils its grain mash. I’ve tasted this product and found it smooth, though not particularly more complex than other vodkas. (Also, they might want to increase its marketing budget — the flash video on the website is hilariously DIY, including a wonderful shot of the warehouse where the vodka is presumably made and an “Amelie”-like montage of the Delos bottle superimposed in front of Texas monuments like the Alamo and the state capitol.)
Sacred gin and vodka are also vacuum-distilled spirits; they’re made in small quantities in London. I haven’t tasted them, but look forward to the opportunity.
Arnold mentioned another tantalizing prospect raised by the new vacuum technology — it enables him to put liquor inside of other things, in one case, injecting a gin martini into a cucumber. “It’s just completely swallowed up inside the flesh of the cucumber,” he says, “an entirely different way to eat and drink.” Oxley gin is a wonderful product, and displays tantalizing potential. But I can’t wait to have it in cucumber form.
Jordan Mackay is the wine and spirits editor for San Francisco’s metropolitan magazine 7×7 and writes The Juice column for Chow. In addition, he’s a contributing writer for Wine and Spirits magazine and a regular contributor to Decanter and the San Francisco Chronicle.
Photo: A traditional copper still. Credit: Ricardo Azoury