How to Thicken a Sauce

January 24th, 2008

How to Thicken a Sauce

Roux is commonly used to thicken sauces like gravies, broths and cream soups, as is the case in my Salmon and Leek Pot Pie Recipe . A roux is a cooked mixture of flour and fat (typically butter). I have seen different fat-to-flour ratios used, typically a 3:2, but you can't go wrong with a 1:1 (especially if we want your sauce a bit thicker like I tend to). If after whisking in the liquid to your sauce you find that you would prefer it be thicker you can always opt for a cornstarch or arrowroot slurry. The thing with roux is that it is necessary to allow enough time for the flour to cook in order to eliminate a 'raw' flour flavor; and that just won't happen if you have already added the liquid.

How to Thicken a Sauce

To make a slurry add 1 tablespoon of cornstarch or arrowroot to a small amount of cold water, dissolve and add to sauce.


  • It is best to simmer your sauce before determining whether it needs to be thickened further. This is going to allow it to reduce, which both removes excess moisture through evaporation while also concentrating its flavor.
  • Arrowroot thickens at a lower temperature than both flour or cornstarch and therefore should be removed from heat as soon as it begins to thicken. Applying unnecessary heat will only cause the mixture to thin out.

4 Responses to “How to Thicken a Sauce”

  1. SorinaNo Gravatar Says:

    You have a very nice blog, good post…keep up the good job

  2. Salmon and Leek Pot Pie Recipe Says:

    […] 3. Melt the butter in a large Dutch oven over medium heat. Add leeks, carrots and 1/2 teaspoon of salt, cook until softened, about 5 minutes. Stir in garlic and cook until fragrant, about 15 seconds. Stir in flour being sure to coat the leeks and carrots. Gradually whisk in clam juice and milk until sauce is smooth. Bring to a simmer and cook until thick, another minute or so. If necessary, check out how to thicken a sauce. […]

  3. barbara coxNo Gravatar Says:

    i want to kinow how to thicken butter with out it curtleing?when i butter my vegies the butter lays at the botton of the bowl?if the butter wa just a little thick it would stick to my vegies thanks barbara

  4. FumiNo Gravatar Says:

    @Barbara Cox – Whisking cold butter into a hot sauce thickens and enriches the sauce. You can also try using little lemon juice or vinegar to emulsify the sauce.

    If you are not okay with emulsions or the idea of using starch such as grain or root for your thickening agents, you can certainly use dairy such as egg/cream, créme fraîch, sour cream, or even yogurt for a healthy low fat alternative.

Leave a Reply