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How To Thicken Spaghetti Sauce (14 of the Absolute Best Ways)

In this article, you will learn about how to thicken spaghetti sauce like a pro and how to keep the watery sauce from ruining your spaghetti night.

Try all of them to see which method for thickening spaghetti sauce is your favorite!

large skillet filled with bright red thick sauce

Everyone loves a good spaghetti dinner. It’s universally appealing, plus it’s simple enough to make even on the busiest night of your week. We all know for your dinner to be a success, the spaghetti sauce has to taste right, and the texture needs to be thick.

Whether you make spaghetti sauce from scratch or try to doctor up a jar of it to pass off as homemade, there is one dilemma that happens to home cooks everywhere…watery spaghetti sauce.

Watery spaghetti sauce doesn’t cling to your pasta. It seeps on down to the bottom of the bowl while your spaghetti has a reddish, wet look to it. All the flavors you intended to coat your pasta with are now merely an afterthought.

But thankfully, you’re here now, and you can learn the best ways to thicken spaghetti sauce, so you’ll never have these watery sauce woes happen again.

How to Thicken Spaghetti Sauce for Tonight’s Dinner

1. Simmer to reduce the sauce

Let’s start with the easiest and best way to thicken pasta sauce. It doesn’t require any additions to thicken the sauce this way, which is great if you have nothing else to work with. The technique is called reduction and is easy enough for anyone to do. All you need to do is let it simmer on low heat for longer to boil out some of that excess liquid.

If your spaghetti sauce is too runny, simply letting it simmer over low heat for an extra 5 to 20 minutes may be all it takes to render it into a lusciously thick sauce that clings to your pasta. However, you’ll need to keep an eye on it. Left too long, it could burn the bottom of your pan. That’s far worse than serving runny pasta sauce!

But what if you don’t have much time to spare? How can you reduce the liquid if time is of the essence? While it’s tempting to turn up the heat, that will only cause the bottom of the sauce to burn. A better way is to grab a pot or pan with a larger surface area. This lets the heat cover your entire batch of the sauce more quickly. It’s more effective too, and it will thicken up more quickly, especially if you have a large pot of sauce.

2. Put more tomato sauce into it

Another way to reduce the liquid in your homemade spaghetti sauce and thicken it up is to add more tomato sauce to it. Because it’s thick, it will help make the sauce feel more balanced.

This is a great trick to thicken the sauce when it comes out a bit bland. It will make the tomato flavor richer, and while you’ll end up with more sauce, you can use what you have left another time for pizzas, sandwiches, eggplant parmigiana, and much more. Don’t forget you can also stow some in the freezer to help you out another night when you have zero time to run to the supermarket.

3. Add tomato paste

If you have a can of tomato paste in your pantry, this will help to create thick tomato sauce. It is even better than adding more tomato sauce to your spaghetti sauce. As the name implies, it’s pasty and thick. And since it’s made with tomatoes, it will only heighten the flavors in your pot.

You can make the sauce thicker by adding tomato paste as you reduce the liquid, though do keep an eye out. You don’t want it going too thick or it could burn to the bottom. Be sure to taste it too to ensure all your herbs and spices are perfectly balanced in flavor.

4. Make a cornstarch slurry

As far as thickening sauces go, cornstarch slurry is a tried and true method that will work. Adding tomato sauce or tomato paste works, but it will require you to adjust the flavors so it doesn’t just taste like tomatoes.

On the other hand, using a small amount of cornstarch and making cornstarch slurry doesn’t change the taste. The key is in adding starch in a small amount and mixing one part cornstarch with one part water.

You can add a tablespoon of cornstarch to a measuring cup and then add a tablespoon of water. Mix them together until they’re well-incorporated. Then, slowly add a little of your cornstarch slurry to your spaghetti sauce, one spoonful at a time. As you add it, stir your sauce, then give it a minute or two to see how it thickens up.

Don’t just dump all the slurry in at once or it could make your sauce too thick. Then you’ll only water it back down and delay dinner even further. Cornstarch can thicken up fairly quickly so it’s best to be patient and add it in little by little to see if you need more or if the amount of slurry you’ve added has done the trick.

5. Use Arrowroot Powder

Arrowroot powder is a great agent to use to thicken your spaghetti sauce. It’s easy to use, and it doesn’t alter the sauce’s flavor.

To thicken spaghetti sauce with arrowroot powder, simply add 1-2 tablespoons of arrowroot powder to the sauce while it’s cooking. Stir constantly until the arrowroot powder is fully dissolved. The sauce will thicken as it cooks.

6. Try making roux

Roux is used famously to make gumbo, but it also thickens those creamy sauces. It is made by mixing an equal amount of fat (usually butter) with flour. Roux changes the flavor of your sauce but in a pleasant way. It’s a bit nutty and the texture is silken. You’ll wind up with a creamier, richer spaghetti sauce but everyone will love it.

However, you should know that you’ll need to make a roux in a separate pan, so plan on washing more dishes after dinner. Making a roux takes only a few minutes and it can really jazz up your spaghetti sauce. To make it, you simply need to keep in mind that you keep the proportions of butter and flour the same.

For a small batch of roux, choose a saucepan and put it over medium heat. You will want to melt 2 tablespoons of butter (or another fat or oil) into it. Once the butter melts and starts bubbling, add your flour in equal proportions to your butter.

Now you’ll need to stay on top of your roux so it doesn’t burn. Keep whisking flour and fat, and you’ll watch it gently bubble. You should lower the temperature so it doesn’t burn. It will take on a golden hue, then continue to become more brown. For using a roux to make thick spaghetti sauce, you’ll want it to turn brown before you add the sauce in.

7. Use your pasta water

This next trick for thickening spaghetti sauce is one that is used when making spaghetti carbonara. If you have reserved your pasta water from boiling the spaghetti, you can use it for the starches it contains.

It might seem counterintuitive to add more liquid to a watery batch of spaghetti sauce. However, due to the starches in the pasta water, it will thicken things right up. You don’t need much thought, so add it in a small amount and keep simmering until you see your sauce thicken.

8. Add mashed potatoes

Potatoes are all starch so make use of your leftover mashed potatoes. This will thicken tomato sauce quickly since it will absorb the excess liquid.

Of course, this trick is best when you have leftover mashed potatoes. If you don’t, you can always make some but if time is of the essence, it’s best to use one of the other methods for thickening spaghetti sauce on this list.

9. Put in egg yolks

Egg yolks will certainly change the flavor of your spaghetti sauce but in a most lovely way. Just like egg yolks make the sauce for carbonara, they can be a wonderful thickening agent for your spaghetti sauce.

That said, you simply can’t just drop raw egg yolks right into your hot and simmering sauce. This will result in scrambled eggs. What you want to do is drop your yolk into a mixing bowl. Then, take just a few tablespoons of your sauce from the pot and mix it with the egg before you slowly pour it into your sauce.

Keep stirring your sauce constantly now, removing it from the heat. The latent heat will cook the egg yolks through to the right temperature without turning them into a kitchen catastrophe.

10. Start off with a rapid boil

Now, if you haven’t yet begun making your spaghetti sauce for tonight’s dinner, you can do this trick to trying to thicken your sauce from the beginning. The secret it getting the sauce up to a rapid boil in the beginning. Watch it like a hawk and when you see the rapid boiling, drop it down to a simmer. W

hen you’re using fresh tomatoes, this will ensure a thick and delicious sauce. For canned tomatoes, make sure you drain them first. Then you can try this rapid boil trick to kick off your pot of spaghetti sauce.

11. Try flour

Maybe you’re out of cornstarch, but you have flour. And if you don’t have time to figure out how to make that roux, simply adding flour can help thicken spaghetti sauce. It’s not the most ideal option, though since plain flour can alter the taste of your sauce.

If you do use flour, use only a little at a time and taste it as you go. You don’t want it to have that starchy taste. You can add other things to enhance the flavor and bring it back to life, though it winds up being more work than anything else on this list.

12. Use breadcrumbs

If you have breadcrumbs in your pantry, you can thicken up your spaghetti sauce and add some more flavor. Beware that it will change your texture, making it have a bit more chew while your sauce thickens.

Flavored breadcrumbs, like the Italian variety, will go in seamlessly. Taste the sauce as you incorporate the breadcrumbs, especially if they’re seasoned. You want the spices to come together harmoniously rather than overwhelm.

13. Add cheese

Do you have cheese to serve with your spaghetti? If so, adding some to the sauce can help to thicken your sauce. The higher quality of cheese you use, the better it will taste. Parmesan is a natural choice and the flavors go well with spaghetti sauce. Freshly-grated is best though you can use the jarred stuff too.

Other cheeses can come to the rescue like cream cheese or cheddar. Make sure you stir it continuously, though, or the cheese will wind up on the bottom of the pot.

14. Drain your pasta well

And finally, this last tip is to prevent problems when serving your spaghetti. You could have done everything right with your sauce. It could be lusciously thick and dreamy, something that would make Nona proud. But if you don’t drain your pasta completely, you’ll be adding water into your thick sauce. This will make your presentation watery and ruin all your efforts in the kitchen.

Let those noodles sit in the strainer for a few minutes and then shake them off well before combining them with your spaghetti sauce.


With these 14 ways of how to thicken spaghetti sauce, you can try combining multiple tips or just use one. Whatever you choose to do though, keep tasting that sauce as you thicken it. This way, you’re sure to keep the flavors consistent even when getting rid of that extra liquid!

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Natalia | Flavorful home
Natalia is a recipe developer, food photographer, and home cook. She started Flavorful Home to document her recipes and share home cooking tips. She loves creating flavorful and nutritious meals while keeping the cooking process simple and joyful!
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