Guests arriving at the Potato Hotel in northern Germany are greeted by a schnapps served in potatoes-turned-tumblers. After taking a bite from the canapés – potato zucchini rolls and sweet potato pie – it should be clear that potatoes rule all at this cosy refurbished farm to the southeast of Hamburg. While waiting for the room key – adorned with a stone potato – visitors can purchase sacks of freshly harvested potatoes at reception. The rooms, some of which used to be cattle pens, are named...