When I travelled to China, I noticed something curious. Almost everyone carried a thermos. Schools had hot-water dispensers. Offices had hot-water dispensers. Hotels provided kettles. People refilled their flasks throughout the day and drank warm water, even during the summer. One of my tour guides told me that when they were children, their mothers would always say that hot water was good for digestion. Drinking hot water had become a habit since childhood. I remember one day after lunch, I wanted to order tea. My tour guide stopped me and took me to a Kung Fu tea house instead. It was like a bar, but dedicated entirely to tea. She…