Recently proven by science, long known by many cultures, there is a 5th category of flavor that we can experience. Sweet, salty, sour, bitter, and now xian-wei. This knowledge was popularized though the Japanese term umami, though the Chinese have also long known of this sensation and termed it Xian-wei.
It’s triggered by certain amino acids, most notably glutamate, which are the building blocks of protein. So, as protein breaks down amino acids are liberated into solution and contribute to the heavenly scent and flavor of fermented foods.
The English word for xian-wei might be savory. I’d certainly like my suan cai to be savory, but a savory beverage could be delicious as well. Something akin to kombucha or ginger ale with added seaweed, mushrooms, or other foods high in glutamate, guanylate, and/or inositol. These are the three known xian-wei triggers.