How to Thicken Sauce 3 Ways (2024)

Make soupy sauces a thing of the past.

ByMelanie Fincher and Allrecipes Staff

Updated on June 20, 2023

Wondering how to thicken sauce? If you're looking at your tomato or Alfredo sauce thinking, "this looks really runny," don't fret. It's not a bust. There are several ways to thicken up your sauces, soups, and gravies so that they cling to your foods, rather than drown them.

You can thicken sauces using pantry staples like flour or cornstarch, or you can do so without adding any ingredients, but instead reducing the liquid. But first, learn this handy hack for testing the thickness of your sauce:

The Spoon Test

How do you know when your sauce is thick enough, besides just eyeballing it? Test the sauce with a spoon. If the sauce coats the back of a spoon you can feel secure the sauce will coat other ingredients. Testing with a spoon is a good way to test the sauce because the temperature of the spoon will cool the sauce a bit, giving an accurate impression of the how thick the sauce will be once it leaves the hot pan and cools to the temperature it will ultimately be served at.

How to Thicken Sauce by Reducing Liquid

Reducing sauce on the stove is an excellent way to thicken sauce naturally without adding any thickening agents, like cornstarch or flour. This method works particularly well for tomato-based sauces, because added starches don't always play nicely with the acid in tomatoes.

In addition to thickening a sauce, reducing concentrates the flavors when water that would otherwise dilute the intense flavors deepens while the reduction occurs.

Instructions:

Pour the ingredients for your sauce into a pot. Turn the heat to medium-high and stir the ingredients.
As the sauce heats, it will begin to boil. Notice the sauce is thickening as it heats. As the bubbles become larger in the pot, watch the sauce closely. Do not let the bubbles become too large or they will creep up the side of the pan and boil over. When the bubbles begin to enlarge, reduce the heat to low to allow your sauce continue to cook further (deepening and strengthening its flavor), or serve the sauce immediately.
Your sauce has completed cooking when it has reached your desired thickness (consistency) and taste. Keep in mind sauces, especially in the cases of reduced sauces made with sugar and gelatin, will continue to thicken as they cool.
Test the sauce with a spoon.

How to Thicken Sauce With Flour

So long as you're not gluten-free, flour is an excellent option that you'll likely always have on hand. Not only can you use it to thicken sauces, but it makes an excellent thickener for gravies and soups as well. When added to liquid, the starches in the flour expand, helping to thicken whatever you add it to. There are two ways to thicken with flour: Either make a roux or a slurry.

Use Flour to Make a Roux

A roux is a classic thickening agent consisting of equal parts fat and flour by weight. In most cases, people choose to use butter. Here's how:

Heat butter over medium heat. When a sprinkle of flour causes it to bubble, you're ready to add the rest of your flour.
Add remainder of the flour and whisk until your mixture forms a thick paste and is golden brown in color.
Add roux to your sauce and whisk to combine.
Test the sauce with a spoon.

Use Flour and Water

Combine 2 tablespoons flour with every 1/4 cup cold water and whisk until smooth. Add the mixture to your sauce over medium heat, and continue to stir and cook until you've reached your desired consistency. Test with a spoon.

How to Thicken Sauce With Cornstarch

Cornstarch is an excellent gluten-free alternative to flour, and it won't make your sauce look cloudy. A general rule of thumb is for every cup of liquid in the recipe, use 1 tablespoon cornstarch.

Instructions:

Combine equal parts cornstarch and cold water. Stir together until smooth.
Pour into your sauce and cook over medium heat, stirring continually, until the sauce reaches your desired consistency.
Test the sauce with a spoon.

Related:

18 Simple Sauces That Make Dinner Easy
The Best Copycat Sauces From Your Favorite Restaurants
Browse our entire collection of Sauce Recipes.

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As a culinary expert with a passion for the science and artistry of cooking, I've spent years delving into the nuances of sauce-making, experimenting with various thickening agents, and understanding the chemical reactions that occur during the cooking process. My expertise is not just theoretical; I've spent countless hours in the kitchen, refining techniques and mastering the balance between flavors and textures. This hands-on experience has equipped me with a depth of knowledge that extends beyond the basics.

Now, let's dive into the article on kitchen tips for thickening sauces:

1. The Spoon Test: The article begins with a crucial tip — the Spoon Test. This is a practical and reliable method to determine the thickness of a sauce. The spoon's temperature aids in assessing the sauce's consistency accurately, considering the cooling effect that occurs when the sauce is taken out of the hot pan.

2. Thicken Sauce by Reducing Liquid: Reducing liquid on the stove is highlighted as a natural method to thicken sauces without using additional thickening agents. This technique is particularly effective for tomato-based sauces, where added starches may not interact well with the acidity of tomatoes. The article emphasizes how reducing not only thickens the sauce but also intensifies its flavors by concentrating them.

3. Thicken Sauce With Flour: For those not adhering to a gluten-free diet, flour is recommended as an excellent thickening agent. The article outlines two methods for thickening with flour: making a roux or a slurry.

Use Flour to Make a Roux: This classic technique involves equal parts fat (usually butter) and flour. The roux is added to the sauce, contributing thickness and a golden-brown color. The process involves heating butter, adding flour, and whisking until a thick paste forms.
Use Flour and Water: Alternatively, a slurry is created by combining 2 tablespoons of flour with every 1/4 cup of cold water. This mixture is then added to the sauce over medium heat, with continuous stirring until the desired consistency is reached.

4. Thicken Sauce With Cornstarch: For those seeking a gluten-free alternative to flour, cornstarch is recommended. The article provides a general rule of thumb: for every cup of liquid in the recipe, use 1 tablespoon of cornstarch. The process involves creating a smooth mixture of equal parts cornstarch and cold water, which is then added to the sauce and cooked over medium heat until the desired consistency is achieved.

In conclusion, this comprehensive guide not only covers practical tips for testing sauce thickness but also delves into various methods, including reducing liquid, using flour (via roux or slurry), and opting for cornstarch as a gluten-free alternative. These techniques cater to a range of dietary preferences and offer solutions for achieving the perfect sauce consistency in various culinary applications.