Miso's meaty umami quality comes from a multi-step process of fermentation, which serves two functions: large molecules get broken down into small, readily-digestable ones, and the fermentation develops a lot of flavor. When it comes to miso, think beyond soups. You can improve an otherwise bland gravy or marinade with it, too.
The first step in making miso: fermenting the fungus Aspergillus oryzae with steamed rice to create koji. It's like malting barley; the fungus introduces enzymes that break starches down into simple sugars. Next, koji is combined with cooked soybeans and salt in a second fermentation. The resulting miso is salty and packed with flavor.
White miso, made with rice, is mild. Yellow miso, made with barley, is a bit stronger, while red miso is especially salty and pungent.