Will the cannabis of the future be brewed in big vats of yeast?

Golden liquid churns in six glass vessels, each hooked up to a computer via a bundle of tubes and wires. Air pumps buzz, and the room smells of bananas and old beer. But this facility – I was allowed to visit on the condition I not use its name or location – is no brewery. Its operators are making cannabis products using microbes instead of plants.

Humans have been cultivating cannabis plants for thousands of years, first for their fibres and later …