The first time I tasted kombucha was in 2010, at a Whole Foods in San Francisco. As I drank the ice-cold bottle of GT’s Multi-Green, I was surprised by how familiar it was: Its sharpness reminded me of long-fermented Taiwanese fruit vinegars… and suan cai, while its funk called to mind the diverse array of ferments, such as furu, tempe, belachan, and doubanjiang, that flavored my ’80s Malaysian childhood.