The Science of Why We Add Baking Soda to Soup

An ultra-smooth pureed soup is dreamy, luxurious—and tricky to pull off. In homemade iterations of the dish, the lush texture of the puree is often marred by fibrous ingredients. There are a few ways of working around this issue—cooking the vegetable for a long time until it breaks down, straining the soup, or adding cream—but we discovered an even easier fix: Baking soda.

Unassuming as it may be, this pantry ingredient is nothing short of a powerhouse when it comes to softening vegetables. Adding baking soda to a soup raises the pH and contributes sodium ions, both of which make the pectin that holds many vegetables’ cell walls together break down faster. The result? Restaurant-level creaminess.

Take our broccoli-cheese soup, for example, where we add baking soda to the cooking water. Just a pinch accelerates the breakdown of the broccoli’s cell walls and more quickly transforms the sulfurous compounds into more pleasant ones. Our broccoli is fully softened in a mere 20 minutes and the soup is super smooth after a quick puree. Want to try this science-based technique in another soup recipe? We use this baking soda technique in our carrot-ginger soup as well.

So, the next time you have a hankering for a creamy vegetable soup, try adding a scant amount of baking soda to your vegetables as they simmer on the stovetop. You’ll make your silkiest soup yet—the perfect blank canvas for a fancy garnish.