In the centre of the factory stand 31 reactors: giant metal globes that can hold up to 10,000 litres of liquid each. Every week, gleaming stainless steel drums arrive by truck at this plant on the outskirts of Oss, in the Netherlands. Their contents are poured into the reactors through a funnel, dissolved, and then heated to boiling point. Standing by one of the vast containers, the factory manager, Robert Dam, compares it to a “cooking pot”. Peering inside, we can see the light liquid bubbling away. At Dam’s factory,…