How to Thicken Soup Without Flour

Match the thickener to the soup

To thicken soup without flour, first decide whether you want a silky texture, a hearty body, or simply less free liquid. Puréed beans or vegetables work well in soups that already contain them. Potato adds weight without changing the flavor much. Cream creates a smooth, rich finish, while cornstarch thickens a clear broth quickly. Reduction is useful when the soup is flavorful but too loose, provided it is not already salty.

Puréed beans, vegetables, or potato

For a naturally thick soup, blend one to two cups of the cooked beans or vegetables with a little broth, then stir the purée back into the pot. An immersion blender can handle part of the soup directly. Potato offers two options: mash cooked potato into the soup for a rustic finish, or simmer peeled potato pieces until very tender and blend them. Add the purée gradually so you can stop at the texture you want.

• Use white beans for a mild, creamy result.
• Blend cooked carrots, squash, cauliflower, or lentils.
• Mash potato for texture; blend it for smoothness.

Cream for a smooth finish

Cream is best when the soup’s flavors suit a richer finish, such as mushroom, tomato, chicken, or vegetable soup. Stir in a small amount over low heat, taste, and add more only if needed. Avoid a hard boil after adding dairy, especially in acidic soups, because the texture can become uneven. Half-and-half or evaporated milk may give body with a lighter finish, but results vary by brand and fat content.

Cornstarch for fast thickening

Make a cornstarch slurry by whisking cornstarch with an equal or slightly larger amount of cold water or broth. Stir it into gently simmering soup, then wait a minute or two before deciding whether more is needed. Add slurry in small increments; too much can make soup glossy or gel-like. Never sprinkle dry cornstarch directly into hot soup, where it can form lumps.

Reduce carefully

For a concentrated, full-flavored soup, simmer uncovered so some liquid evaporates. Stir occasionally and watch the bottom, especially with thick or starchy soups. Reduction is the simplest option when seasoning is balanced, but it also concentrates salt. If the soup already tastes salty, choose puréed beans, vegetables, or potato instead, or add an unsalted thickener rather than cooking the liquid down further.

A simple finishing method

Take the soup off the heat briefly, add one thickener in a small amount, and stir thoroughly. Return it to gentle heat and reassess after a minute or two. You can combine methods—for example, purée vegetables first, then add a small cornstarch slurry—but change one thing at a time. Taste for salt only after the final texture is set, since thickening can make seasoning seem more pronounced.