When it comes to food, you have to feel sorry for those poor astronauts. Limited to quick-serve pre-prepared and pre-packaged foods, most astronauts are sure to get cravings for things only found on Earth, like french fries. With that in mind, the European Space Agency recently supported the work of chemists at the Aristotle University of Thessaloniki in Greece, who experimented with deep-frying in space.
Cooking in space isn't an easy task. You have to consider that the ingredients involved float in zero-gravity, and the physics of how heat distributes through food is completely different in space. Imagine trying to make something as simple as coffee: in zero gravity, the water can’t drip down through the coffee grounds: it would just float there, doing nothing. Cooking with fire would also be tricky (and dangerous), since fire takes on a different shape without gravity.
Unfortunately, it’s difficult to simulate zero gravity, so the chemists decided to go in the opposite direction and study cooking in increased gravity, similar to that found on Jupiter. Working with the much beloved french fry, they considered how oil would behave with more gravity. On Earth, hot oil rises through convection. In increased gravity, that should happen even faster and be more evident. The team attached a deep-fryer, filled with potato strips and oil, to a centrifuge, which simulates a higher level of gravity. As the potatoes cooked, they measured the temperature of the crust of the french fries. As g-forces rose to about 3g, bubbles in the oil multiplied and rose faster, cooking the fries at a rapid rate, making them nice and crispy (yum). At higher g-forces, though, the bubbles became so tiny that they stuck to the potato sticks, resulting in soggy fries (ew).
So what did the chemists learn? If you want to cook french fries faster and make them good and crispy, 3g is the magic amount of gravity needed to make that happen. Anything over that, though, results in a disgusting mushy mess. Using these findings, the research team hopes to work with less gravity (at least less than what’s found on Earth) and see how that affects cooking. If all goes well, and with a near-future colony on Mars, McDonald’s might want to plan its first franchise off-world.