> * It's a fermentation process, so it takes heat and water, not just air. To be fair, if the heat is from solar or wind energy, and the water is collected fro

> * It's a fermentation process, so it takes heat and water, not just air. To be fair, if the heat is from solar or wind energy, and the water is collected from rain (which I guess includes river water?) then those are also "out of thin air". Or I suppose you could say that air containing rain is not as thin (i.e. contains more mass) than "normal" air, or that "air" only refers to the gases, not the rain falling through it, in which case they'd have to rely on moisture vaporators, like in Star Wars.