Context is everything. Drinking a cocktail containing an aquatic beetle and a water lily might prove disconcerting, but in the lab of John Bush, a fluid dynamicist at MIT, and the kitchen of José Andrés, a well-known culinary innovator, these natural inspirations give rise to mixed drink magic. The aquatic beetle is transformed into an edible liquor-dispensing boat and the lily into an elegant floral “pipette” which captures and dispenses small amounts of drinks.
The edible cocktail boat relies on the same locomotion as do many aquatic insects, both exploiting the Marangoni effect to propel themselves across water. Where liquids of two surface tensions meet, a gradient is created with a propulsive force towards the liquid of higher tension.
The boat, only about 1.5 cm (0.6 in) across, has a small notch in the back to release alcohol. When the boat is filled with higher proof alcohol than the surrounding drink, the boat is launched forward as it dispenses its cargo. In experiments, the team found a boat design that would motor around for two minutes at speeds of 10 cm/sec (3.9 in/sec), before running out of “fuel."
While initial designs were 3D-printed, molds were created for the ThinkFood team, allowing for tastier boats of gelatin, agar, melted wax, and candy.
The flower pipette actually demonstrates the opposite behavior than its inspiration. Aquatic flowers in nature are forced close by the hydrostatic force of oncoming water, and capillary forces within the flower prevent any water leaking in. In the cocktail version, the flower-shaped pipette is lowered into the liquid and as it’s drawn up, hydrostatic suction closes the flower while surface tension within the pipette prevents any alcohol from spilling all over the imbiber.
ThinkFood experimented with gelatin, agar, and combinations of locust bean gum and carrageenan to create an edible version of the pipette that would behave similarly to the prototypes. A 3D-printed version contains an LED in the center of the flower for style.
While the floral pipette may be a novel way to cleanse the palate between courses, and the edible boat an intriguing method of infusing small amounts of differently flavored or colored spirits, both represent the increasing collaboration and mutual inspiration between scientists and gastronomists. Both are, as Bush says, “familiar with a rich culture of all that has come before them” and recognize a challenge to “combine things in novel, interesting ways.”
The boat and the pipette can be seen in action, in the video below.