McDonald’s new Chocolate Shamrock Shake presents food-mixer purists with a problem: There is a layer of mint and a layer of chocolate, and they need to be consumed together. Realizing this frankly very minor life inconvenience was nonetheless a problem the multi-billion-dollar chain could solve, it decided to reengineer the common straw by hiring a crack team of robotics and aerospace engineers. Thanks to the principles of fluid dynamics, it’s now possible to get the perfect 50-50 chocolate-to-mint ratio in every sip.
The device — called the Suction Tube for Reverse Axial Withdrawal (or just … STRAW) — sort of resembles a snorkel that maybe got wrested from a shark’s jaw. It has three more holes than usual; two are near the open end and go all the way through both sides, and there’s another straight one along the very bottom. All of them are functional, but the hole at the bottom is the game changer, closing the pressure system off once the tip of the straw’s J shape gets exposed to the air. Fast Company, which got to test one, calls it a “product of comedic over-engineering,” and notes that the R&D involved white boards, CAD models, and a distressing amount of head-scratching. “But it works,” their review concludes, though, for what it’s worth, it couldn’t suck up the final bits of shake from the bottom of the cup.
One of the project’s engineers, the head of Google partner NK Labs, confesses the redesign did present “quite a few” challenges, surprisingly. “A lot of designs we came up with would work well when the shake was full, or might work when the shake was empty,” he tells Fast Company, “but in a lot of situations, we found if we didn’t get the diameters just right, we’d end up drawing in air.” Luckily for America, though, they paid attention when the Fibonacci sequence was being explained in class. Their STRAW is available only in a limited-edition run of 2,000, alas, but it’s free if you can get your hands on one at a participating McDonald’s. If demand is just through the roof, the company says the bent piece of metal could see wider release at a later date.