The solvent, a mixture of ethanol and water, keeps the fibers from falling apart as they fling out of the supercharged cotton candy machine. The fibers themselves are made of pig-derived gelatin, which is a product of broken-down collagen. In a regular steak, collagen forms what’s known as the extracellular matrix, or the scaffolding that holds the meat together. How it's cooked, then, defines its structure and flavor. For instance, you’ve probably had at least one terribly cooked steak that curls up at the edges. “It's not very tasty, it's pretty dry,” says Parker. “The collagen curled up instead of transitioning into gelatin.” By contrast, in slow-cooked pulled pork, the low temperatures give collagen the chance to turn into flavor-packed gelatin. And by using gelatin to make these fibers, the researchers can create a tender meat analog.

Speaking of pulled pork, you know how it comes apart into that mass of fibers? That’s because skeletal muscle cells fuse together into long strands. With these lab-spun gelatin fibers, the researchers provided a similar kind of scaffolding, to which they added either cow or rabbit cells. “You don't want the cells to be like bricks in a brick building,” says Parker. “You want them to be nice and long, like that pulled pork. So having these long fibers, the cells attach to the fibers and they form protein junctions, and then they grow along the length of the fiber.”

Rabbit cells (the white bits) adhere to the gelatin fibers. Photograph: Harvard University

The end product is a meat analog whose consistency rivals the real thing. Parker and his colleagues ran a “texture profile analysis”—more or less a little metal hammer that presses down on the material to test its consistency. “Lo and behold, the chewability, or the toughness of this meat, is pretty similar to the other kinds of meat that you might see in the store,” adds Parker.

Now, some big caveats here: The researchers didn’t do a taste test because for one, this isn’t a food-safe lab. Also, this lab-grown meat isn’t cooked, which will transform it in complex, yet to be studied ways. And growing the animal cells—whether in a petri dish, as other lab-grown meat companies are tinkering with, or on these gelatin fibers—is still a tricky process that requires the right temperature, moisture, and nutrient content.