QUESTION: Why does absinthe change color with the addition of ice water?
If you want to properly enjoy a premium grade absinthe, you must begin by pouring a 1 jigger serving into your absinthe glass. Sugar cubes are optional, and if you were to do so, grab your sugar spoon with a cube, both placed on top of your absinthe glass. Then, the ceremony truly begins. You have your ice-water fountain or your see-saw dripper positioned above the sugar cube. Then you let her rip. Slowly, as droplets of ice water fall over the sugar cube, dissolving it, you begin to notice the hue of your absinthe begin to change. At first, it evolves subtly, with little flashes of oil bouncing around the bottom of your glass. This is, shall we say, the green fairy’s delicate rain dance. Suddenly, the bottom of the glass is less translucent, acquiring an opalescent appearance—the storm begins to consume the sky as your absinthe begins to “louche.” Finally, once your glass reaches a 3:1 water-to-absinthe ratio, you witness the full transformation. You can no longer see through your drink—the storm has arrived in full swing. So why does the colors change so dramatically with the addition of water?
Absinthe is distilled using a variety of botanicals, including the “Holy Trinity” of Grande Wormwood, Aniseed, and Fennel Seed, amongst other herbs, all of which impart essential oils that are locked in solution with ethanol, an excellent solvent. Once water is added, the essential oils are brought out of solution where they then capture light giving a green opalescent appearance, a phenomena on referred to as “spontaneous emulsification,” or the “ouzo effect.”
Robert Botet describes the “ouzo effect” in the Journal of Physics, where combining a “totally water-miscible solvent and a hydrophobic oil into water, generates spontaneously nanometric droplets which are stable, even without surfactant.” This “louching” phenomenon captivated the hearts and imaginations of the world’s greatest artists, including Vincent Van Gogh, Oscar Wilde, Henri de Toulouse-Lautrec, and Pablo Picasso, all of which had a boisterous sense of flare. Aesthetes were particularly drawn to the pomp and circumstance of large, ornate absinthe fountains, which economized the use of ice, a particularly expensive commodity in the late 19th ce.
Fast forward to the present. Since prohibition has lifted post 2007, absinthe is growing in popularity with several brands popping up on the market. It is noteworthy to mention that adequate louching is a marker by which one grades the overall quality of the absinthe. If absinthe doesn’t louche, then it is of low quality. And unfortunately there are many imposters out there today pedaling low-quality absinthe, ruining the reputation of this unique category of spirits. Many factors contribute to whether or not an absinthe louches, some of which include distillation practices, whether the process adhered to traditional formulation, or if short-cuts were taken by simply adding flavoring rather than authentic botanicals run through a standard distillation process. To fight against this, we at Absinthe Minded take pride in using 100% natural botanicals with no artificial flavors. With that, we are doing everything we can to bring quality to the absinthe revival movement in America. Cheers!