WIRED wants to take you on the deepest dive yet into the science behind the Impossible Burger.
Biting into an Impossible Burger is to bite into a future in which humanity has to somehow feed an exploding population and not further imperil the planet with ever more livestock. Because livestock, and cows in particular, go through unfathomable amounts of food and water (up to 11,000 gallons a year per cow) and take up vast stretches of land. And their gastrointestinal methane emissions aren't doing the fight against global warming any favors either (cattle gas makes up 10 percent of greenhouse gas emissions worldwide).
This is the inside story of the engineering of the Impossible Burger, the fake meat on a mission to change the world with one part soy plant, one part genetically engineered yeast—and one part activism. As it happens, though, you can't raise hell in the food supply without first raising a few eyebrows.
[...] Technicians take genes that code for the soy leghemoglobin protein and insert them into a species of yeast called Pichia pastoris. They then feed the modified yeast sugar and minerals, prompting it to grow and replicate and manufacture heme with a fraction of the footprint of field-grown soy. With this process, Impossible Foods claims it produces a fake burger that uses a 20th of the land required for feeding and raising livestock and uses a quarter of the water, while producing an eighth of the greenhouse gases (based on a metric called a life cycle assessment).
Now, engineering a "beef" burger from scratch is of course about more than just heme, which Impossible Foods bills as its essential ingredient. Ground beef features a galaxy of different compounds that interact with each other, transforming as the meat cooks. To piece together a plant-based burger that's indistinguishable from the real thing, you need to identify and recreate as many of those flavors as possible.
To do this, Impossible Foods is using what's known as a gas chromatography mass spectrometry system. This heats a sample of beef, releasing aromas that bind to a piece of fiber. The machine then isolates and identifies the individual compounds responsible for those aromas. "So we will now have kind of a fingerprint of every single aroma that is in beef," says Celeste Holz-Schietinger, principal scientist at Impossible Foods. "Then we can say, How close is the Impossible Burger? Where can we make improvements and iterate to identify how to make each of those particular flavor compounds?"
This sort of deconstruction is common in food science, a way to understand exactly how different compounds produce different flavors and aromas. "In theory, if you knew everything that was there in the right proportions, you could recreate from the chemicals themselves that specific flavor or fragrance," says Staci Simonich, a chemist at Oregon State University.