Umami boosters be damned — there’s no replacing the metallic richness of a medium-rare steak.

Which is reason for concern, because our meat-eating days are numbered. Cows take up too much land, eat too much grain, and fart too much methane for our appetite for beef to be sustainable much longer. Will meat lovers be forced to accept miso and marmite as umami substitutes forever?

The scientists at Impossible Foods, who are out to create the world’s most convincing veggie burger, think they’ve figured out the secret to replicating the flavor of meat. It comes down to one question: What’s meat got that vegetables don’t? In a word: Blood. And in blood lies a protein called heme, the molecule that could revolutionize the fake-meat industry.

Heme makes up part of the molecule hemoglobin, which turns blood red and carries oxygen around the body. It’s characterized by its ability to carry iron, so on its own, the molecule pretty much tastes like spare change.

The fact that heme isn’t just found in animal blood is what piqued Impossible Foods’ interest. It’s found in virtually all living things, including bacteria and plants. Lance Ignon, a representative for the company, told Inverse that they source their heme from the nitrogen-fixing root nodules of legumes, where it’s a component of the oxygen-carrying protein “leghemoglobin” — kind of like hemoglobin, for beans. This is what gives the company’s veggie burgers their “unmistakable meaty flavor.”

Crafting a truly convincing burger is, of course, more complicated than simply dousing plant fibers with heme, but the molecule does seem to act as the magic catalyst that brings all of the burger’s other flavors together.

“It’s the combination of the right proteins, amino acids, sugars, and fats that come together to create the distinctive flavor of meat,” Ignon says. “But heme is the catalyst for the explosion of chemical reactions that take place when meat is cooked, transforming the simple nutrients found in the raw meat into the unmistakable flavor and aroma of cooking meat.”

Will heme be the fake meat game changer the world is waiting for? By the looks of it, it bloody well could.

Photos via Impossible Foods