The Major Mistake To Avoid When Making Miso Soup

Whether enjoyed as an appetizer to a sushi feast or on its own when you're feeling under the weather, miso soup is the ultimate umami-packed comfort dish. While you can certainly order one from your favorite local takeout spot, the Japanese soup is surprisingly easy to make yourself. Per Tasting Table's own simple miso soup recipe, you can whip up a pot for six in as little as 25 minutes, from prep to finish.

The overarching process, for the most part, is the same as making any other soup — you boil the broth, add in your solid ingredients, and simmer until everything's softened and it's time to serve. But there is one major mistake you'll want to avoid in the process — boiling your soup after you've added its namesake ingredient. As Lucy Seligman, the cookbook author and food historian behind Thanks for the Meal, explained to Tasting Table, "After adding in the miso using a miso muddler, never boil the soup again. That would make the miso taste bitter."

Potent as its flavor may be, the fermented soybean condiment actually requires a rather delicate touch to maintain an ideal balance of taste, aroma, and like other fermented foods, an ecosystem of live cultures. Extremely high heat, such as that found in a pot of boiling liquid, can disrupt the miso's flavor profile — not to mention killing off the "good" bacteria that provide us with potential health benefits, from aiding in digestion to offering immune support (per Healthline).

Indeed, incorporating the oh-so flavorful (yet oh-so fickle) miso paste should come as the final step of making soup, either while the pot sits over a low simmer or after the heat has been turned off completely. This prevents the potential of ruining its flavor with any need for additional boiling, which, as Lucy Seligman warns, can leave it with an unpleasant taste. 

But that's not the only thing you need to know about miso when using it in soup. You should also be sure not to drop a scoop directly into your pot, which may result in lumps and clumps of undissolved paste. Instead, you should let the paste dissolve in a separate bowl first, then, once sufficiently whisked, smoothed, and dissolved into a liquid component, you can pour it into your final mix. As Tasting Table's own recipe developer Miriam Hahn recommends, you can achieve this by ladling out some of your hot broth into a bowl and stirring the miso into that.

As Seligman mentions, you also have the option of using a miso muddler to ensure the paste is sufficiently mixed. The Japanese kitchen tool, which you can purchase for less than $20 on Amazon, resembles a double-sided whisk and is designed to measure, scoop, and help easily dissolve the paste, whether you're getting creative with your miso or simply mixing it into the broth. It's a nifty tool to keep in your arsenal, especially during (miso) soup season.