It’s a staple Chinese food, has been around for centuries and is beloved by vegetarians and vegans the world over. But you’d be hard pressed to find many people who know how to make tofu.

Known in China as ‘doufu’, Cao Aimin and his ancestors have been cooking beancurd in their Hebei Province kitchen for more than 100 years. He now runs the kitchen with his wife and biggest tofu fan Feng.

The hours are long making tofu from scratch. First, Aimin soaks the soya beans before adding bittern, a dehydrated sea salt. Next he drains the water and presses the beancurd into shape.

But according to Feng, the results are worth it – the tofu tastes better which makes her job selling it much easier.