Miso soup is divine in its simplicity, as it requires just a few ingredients — most of which you can find at your local grocery store. The base ingredients for making miso soup's base (dashi) keep well in the pantry, while the miso itself has a long refrigerator shelf life. Once you stock your kitchen with three essentials, you'll only need to pick up a few accompaniments when the craving for miso soup strikes.
Kombu is dried kelp which has been cut into sheets. This is the most obscure ingredient that you'll need for miso soup, but since it is dried it also lasts the longest. Some chain grocers, like Whole Foods and Trader Joe's, keep kombu on hand, but all Asian markets keep it on their shelves. Kombu can also be ordered online from retailers like Amazon or Thrive Market.
You'll see kombu packaged in plastic sleeves and labeled everything from Dashi Kombu, Sea Vegetable, to Sea Kelp. The clear plastic packages are great because you can sneak a peek at the kombu's quality. Look for kombu with lots of white crystalline residue on its surface — that is the glutamic salts which make kombu dashi so flavorful.
Learn more: Ingredient Spotlight: Dried Kombu
Traditional miso soup dashi is made with both kombu and bonito flakes, or katsuobushi. Bonito flakes are made from dried bonito fish that have been thinly shaved. These flakes also have a long shelf life (when left unopened) and many uses beyond miso soup. Try tossing bonito flakes with grilled shishito peppers or with grilled chicken wings.
Look for large flakes that have a tender curl and lots of body. These can also be procured at the Asian market or bigger retailers like Whole Foods and Amazon. If you can find bonito flakes in smaller packages, snatch them up, as once opened the flakes quickly use their flavor. Store opened bonito flakes in an airtight container (or zip-top bag) in the fridge or freezer to extend its shelf life after opening.
Miso is fermented soybean paste made by mixing soybeans with water and a koji grain that has been inoculated with mold spores. The soybeans ferment for weeks or years before becoming the thick paste we love for its deep umami qualities.
Miso is widely available in three main varieties. White is typically sweeter and lighter, with the shortest fermentation period of the three. Yellow is fermented at least a year, with a balanced mix of sweetness, acidity, and pungency. Red is the darkest of the three, with a complex depth of flavor produced by a longer fermentation. You may also find local and Japanese miso varieties with less distinct labeling; you may need to probe the shop keeper or the miso-maker to understand their varietals, but these are worth seeking out.
There is no wrong miso for making miso soup — so I urge you to pick up two or three containers at your local Asian market and experiment. Miso lasts up to 18 months in the fridge and you can add a dollop to everything from soup to oatmeal.
Learn more: What's the Best Type of Miso for Miso Soup?
Tofu is also made from soybeans and becomes the perfect protein for miso soup. Buy fresh silken tofu from the produce section for making miso soup. Firm tofu becomes spongy in the soup and won't quickly absorb the soup's delicate flavors the way silken will. Since tofu only has a shelf life of just three months, its something you'll need to shop for regularly to keep the miso cravings at bay.