It’s one of the most commonly consumed snacks in the Western world and has been made in one form or another for at least three centuries, so you might think nothing new could come of the humble french fry. But British chef Heston Blumenthal put paid to that notion years ago. He and his research chef Chris Young came up with a triple-cooked “chip” with a taste and texture that blow away anything you will find at a burger joint. Other chefs have raised the bar further. Nils Norén and Dave Arnold of the French Culinary Institute in New York City, building on work by a Polish researcher, figured out how to improve the texture inside fries by treating the potatoes with an enzyme. The chemical helps break apart the pectin in the fries, yielding a smoother mouthfeel.
Inspired by these heroic efforts, Maxime Bilet, Johnny Zhu and the other research chefs (including Young) at our culinary lab in Bellevue, Wash., explored a variety of techniques for doing better still. The winning combination is simple in its ingredients but quite fancy in its execution. The potato batons are vacuum-sealed with 2 percent salt brine in bags to keep them intact during boiling. They are then bombarded with intense sound waves from the same device that dentists and jewelers use. A lengthy ultrasound treatment at 40 kilohertz causes the surface of each fry to crack and blister with myriad tiny bubbles and fissures.
The cook next vacuum-dries the pretreated potato sticks to adjust the water content of the exterior and then briefly blanches them in oil at 340 degrees Fahrenheit to tighten their network of interlaced starch molecules. After cooling comes the final step: a quick plunge into hot oil at 375 degrees F. Water flashes to steam inside each minuscule bubble on the surface of the fries, expanding in volume by a factor of more than 1,000 and forcing the bubbles to puff up. In just a few minutes of deep frying, the french fries take on an almost furry appearance.
These wonders of 21st-century cooking are unlike any fries you have tried before. A hugely satisfying crunch when you bite through the exterior yields to a center of incredibly smooth mashed-potato consistency. Although there are several steps involved in the process, it is amenable to automation by a food manufacturer. So maybe one day you won’t have to settle for flaccid, featureless fries with your fast-food meal.
This article was originally published with the title Ultrasonic French Fries.