According to food writer and DIY activist Sandor Ellix Katz, the English language uses the word “fermentation” to describe both the literal process of yeast and bacteria transforming nutrients in foods and beverages, but also any phenomenon that is bubbly and dynamic. Some fermentations occur within hours such as yogurt, while other processes take a year or longer, like soy sauce or miso. Waiting doesn’t always come easily. Katz’s new book, “ Fermentation as Metaphor ” grapples with the challenges and gifts of fermentation, and how it relates directly to human culture and daily lives.