Bring the sauce to a boil over medium heat.

There are many times when we need to thicken a soup, stew or sauce. But what’s the best way to do it without creating a lumpy mess?

The Best Way to Thicken

First things first: Never sprinkle flour into the soup, stew or sauce and hope that this will work. It will just go lumpy and will taste like raw flour. Instead, there are specific ways you should thicken your liquids.

There are two good ways that should just about cover most situations:

  • A Cornstarch Slurry
  • A Roux

Cornstarch Slurry

The easiest and most versatile is the cornstarch slurry, which is simply a smooth paste made by combining equal portions of cornstarch and liquid. The liquid does not have to be water. Some choose to use wine or stock.

There are a couple of things to remember to ensure that it mixes in smoothly and does not clump:

  • The liquid you choose to use must be cold
  • Whisk the cornstarch and liquid with a fork until it is completely smooth
  • Always add the cold slurry to simmering hot liquid (soup, stew, or sauce)
  • When adding the slurry, stir constantly as it will thicken quickly
  • If you make your slurry ahead of time, it may separate by the time you are ready to use it. Give it a stir before adding it to the soup/stew/sauce


For every 1 CUP of soup/stew/soup, use:



Roux, which rhymes with “you,” is another option for thickening. This is used to keep a sauce nice and viscous, so it doesn’t turn into a soup. There are three basic types of roux, classified by colour. The type of roux you get depends on how long you cook it:

  • The shortest time is a “White Roux” (Cooked for 3-4 Minutes)
  • Followed by “Blonde Roux” (Cooked for 4-6 Minutes)
  • Lastly “Brown Roux.” (Cooked for 6-8 Minutes)

For every 1 CUP of soup/stew/soup, use:

14 g FLOUR and 14 g BUTTER (Equal parts by weight)

What is your preferred method to thicken soups, stews, and sauces? Let us know in the comments below.


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