How to Thicken Pasta Sauce (3 Ways)
Published 3/11/2022 • Updated 8/17/2024
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No matter how closely you follow a recipe, sometimes you end up with a watery pasta sauce. Have no fear, it is very easy to thicken pasta sauce with one of these 3 ways!
How to Thicken Sauce
Have you ever made yourself a delicious pasta dish and for some reason the sauce isn’t as thick as you want it? Have no fear, you can still save your pasta sauce and, any sauce for that matter!
In this post, we’ll teach you how to thicken up your sauce 3 different ways:
- Roux
- Starchy Pasta Water
- Cornstarch Slurry
Make a Roux
Making a quick roux is an easy way to thicken any pasta sauce. Whether you are making a cheese sauce or just thickening a pasta sauce.
A roux is usually equal parts flour to fat (1:1). We use all-purpose flour and unsalted butter. We like to use a roux when we wanted a richer pasta sauce.
How to make a roux
- Heat a separate saucepan (meaning not your pasta sauce pan) over medium heat.
- Add the butter to the saucepan and when the butter is melted, add flour to the saucepan and whisk the two ingredients together.
- Let the flour and butter cook for 1-2 minutes until a paste forms.
- Whisk the roux into your pasta sauce and bring the sauce to a simmer over medium/high heat. Your sauce should thicken quickly.
Starchy Pasta Water
Starchy pasta water is magic unicorn when it comes to pasta sauce because you don’t have to do much. The trick is to remember to set aside pasta water when before you strain your pasta.
Try it in our cream cheese pasta sauce or garlic parmesan pasta.
How to Use starchy pasta water
- Bring a large pot of salted water (be sure the water is very salty). Add pasta and cook until al dente.
- Before straining the pasta, remove one cup of starchy pasta water from the pot. We like to set aside more pasta water than we will use just in case!
- Add 1/4 cup of the pasta water to your pasta sauce and bring the pasta sauce to a gentle boil. Your pasta sauce should thicken as it simmers.
Latest Pasta Recipes
Make a Cornstarch Slurry
A cornstarch slurry is also a fast and easy way to thicken your pasta sauce. Generally you want to use a 2:1 ratio (water:cornstarch) when making a slurry. The cornstarch is activated when it is heated.
We like to use a cornstarch slurry in pasta sauces with strong flavors like Asian-inspired pasta dishes, tomato sauces, mushroom pasta sauce, etc. Why? Because the cornstarch flavor can be overpowering if you are using it in a basic pasta sauce.
We like to make a slurry rather than just adding cornstarch to a pasta sauce to avoid little clumps of cornstarch in the pasta sauce.
How to Make a Cornstarch slurry
- Add water and cornstarch to a small bowl and whisk the two ingredients together until the cornstarch has dissolved.
- Whisk the cornstarch into your pasta sauce and bring the sauce to a gentle simmer. The pasta sauce should thicken quickly as it simmers.
Why isn’t my pasta sauce thick?
You can end up with water-y pasta sauce for a few different reasons. Even if you follow a recipe exactly, there are few things that can cause a pasta sauce to be too thin.
The moisture content of vegetables that you use. Vegetables release liquid when you cook them down. Sometimes some vegetables have more than others and can leave you with extra moisture.
You didn’t allow your pasta sauce to simmer and reduce. If we are in a hurry sometimes we don’t allow our pasta sauce to reduce enough.
Too many liquid based ingredients were added. Sometimes we when we wing a pasta sauce we go overboard and use oil, broth, cream, and water and we are left with a water-y sauce.
FAQ
You can thicken pasta sauce with a roux, pasta water, or a cornstarch slurry.
We recommend making a roux or using starchy pasta water to thicken your pasta sauce.
Your pasta sauce won’t thicken because there is too much liquid and (generally) not enough starch.
Yes, adding pasta water can thicken the sauce as long as you let the pasta sauce simmer once you’ve added the pasta water.
How to Thicken Pasta Sauce (3 Ways)
Ingredients
Roux
- 1/4 cup unsalted butter
- 1/4 cup all-purpose flour
Cornstarch Slurry
- ¼ cup water
- 2 teaspoons cornstarch
Starchy Pasta Water
- ¼ – 1 cup starchy pasta water
Instructions
Roux
- Make a roux in a separate saucepan than your pasta sauce.
- Heat a small saucepan over medium heat. Add the butter.
- When the butter is melted, add the flour to the saucepan and whisk the two ingredients together.
- Cook the roux for 1-2 minutes and then whisk the roux into the pasta sauce (be sure the pasta sauce is warm).
- Bring the pasta sauce to a gentle simmer, the pasta sauce should begin to thicken quickly.
- If the pasta sauce isn’t as thick as you’d like, repeat steps 1-5.
Cornstarch Slurry
- Add ¼ cup water to a small bowl and add cornstarch to the water.
- Whisk the two ingredients together until the cornstarch is dissolved.
- Whisk the cornstarch slurry into the pasta sauce (be sure the pasta sauce is warm).
- Bring the pasta sauce to a gentle simmer, the pasta sauce should thicken quickly.
- If the pasta sauce isn’t as thick as you would like, repeat steps 1-4.
Starchy Pasta Water
- When cooking pasta for your pasta sauce, remove 1 cup of starchy pasta water from the pot before straining the pasta.
- To thicken the pasta sauce, start by adding ¼ cup of pasta water to your pasta sauce.
- Whisk the starchy pasta water into the pasta sauce and bring to a gentle simmer.
- The pasta sauce should begin to thicken.
- If the sauce isn’t as thick as you would like, add 1 tablespoon more of starchy pasta water to the sauce at a time until the pasta sauce is thickened.
Tips & Notes
- The nutrition information is just for a roux.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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