To grow meat from animal cells, you need three basic things. First, and perhaps most obviously, you need cells. Second, those cells need to be fed, so you’ll also need a nutrient-dense liquid medium. And finally, you need a bioreactor, which is one of the biggest challenges this nascent industry has yet to overcome.
Think of a bioreactor as a mechanical cow. Inside a real animal, you have a tissue structure that contains skeletal muscle cells, blood vessels, and intramuscular fat. Most companies right now are working to grow muscle cells, rather than fat.
In a bioreactor, these cells float in the liquid medium, blithely munching away on a man-made concoction of proteins and other nutrients cells need to grow and proliferate into fat and muscle tissue. The bioreactor is supposed to create an environment that can mimic what happens inside a live animal to grow cells. That means, among many things, maintaining a certain temperature, regulating pH levels, and ensuring enough oxygen is moving around the tank.