How To Thicken Spaghetti Sauce – 7 Methods

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A watery sauce can turn a pasta dish from wow to meh. It can be super frustrating and disappointing, but it is not the end of the world.

There are many ways to thicken spaghetti sauce, and in this article, you will find seven methods to do it— plus a few helpful tips!

Let’s get started!

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How do you fix runny spaghetti sauce?

Whether it is because the tomatoes weren’t meaty enough or you’re just not happy with the consistency of your sauce, there are several ways to thicken tomato sauces. In essence, it all boils down to two options: add more ingredients to increase the density of the sauce or reduce the liquids

However, you should be aware that some alternatives might change the flavor of the sauce. For example, some people recommend adding cheese, and although it can improve the consistency of the sauce, it will also affect the taste of the original recipe. So, you have to be wary when using more ingredients.

Additionally, before serving, make sure to strain the pasta thoroughly. Otherwise, excess water in the pasta may affect the consistency of the sauce, not to mention that it will also take away some flavor.

That said, these are the seven best methods to fix thin sauces:


Simmering is the easiest way to thicken spaghetti sauce without compromising the flavor, and it doesn’t require extra ingredients.

All you have to do is leave the sauce on the stove over low heat until you are satisfied with the consistency. The heat will evaporate the excess liquid and improve the texture of the sauce. 

Be sure to leave the pan uncovered so that the water does not condense on the lid and run back into the sauce. Also, remember to keep an eye on it and stir it regularly to avoid burning.

This method might take anywhere between 5 to 30 minutes, depending on how runny the sauce is. For better results, use a saucepan instead of a regular pot so that the heat can distribute more quickly and evenly.

Bear in mind that although simmering is pretty effective, it might take some time, so it is not the best option when you are in a hurry or when the sauce is too watery.

Making a roux

A roux is a mixture of flour and fat used to thicken sauces and soups. It requires a little more effort than other methods but provides a creamy texture for a much more flavorsome sauce.

To make a roux, you should cook equal parts fat and flour together until you get a thick, smooth batter. Most people use butter as a source of fat, but you could use oil instead.

Not sure how to prepare a roux? Follow these steps:

  • Melt 4 tablespoons of butter in a pan at low heat.
  • Add 4 tablespoons of all-purpose flour and stir to mix both ingredients. To avoid lumps, you can add the flour little by little.
  • Stir at low heat for about 3 to 5 minutes or until you get a creamy, slightly blond slurry. It is crucial to keep whisking the mixture to avoid burning.
  • Once you have a homogeneous mixture, you can turn off the heat and add it to your sauce.
  • Mix slowly, let it simmer a bit, and that’s it! Now you have a thick, flavorful spaghetti sauce.

Note that the more you cook a roux, the darker it gets. A roux can be white or blond for light sauces or brown for dark gravies. In this case, you should aim for a slightly blond roux, taking care not to overcook it to avoid unwanted flavors in the sauce.


Cornstarch is, perhaps, the most popular thickener for sauces, soups, and pretty much everything that needs more consistency. It is super versatile and potent— it is almost like magic! What is best about it is that it is flavorless and provides a creamy, glossy texture for a much stronger sauce.

To thicken a sauce with cornstarch, you have to dissolve it in water first. Otherwise, you will get a clumpy mess!

Add equal parts water and cornstarch in a small bowl and mix both ingredients with a fork until you get a smooth slurry. Then, pour the mix into your sauce, stirring constantly, and ta-da! It is as simple as that.

You do not need to use a lot of cornstarch to achieve the ideal consistency. In most cases, two tablespoons will be more than enough. However, the good thing about this method is that you can add small amounts progressively until you are satisfied with the thickness of the sauce.


Egg yolks provide a creamy texture to your sauces, and they won’t make significant changes to the flavor. But, there are a few things you should consider.

Since egg yolks can cook quite fast if you add them directly into the hot sauce, you must first temper them. So, if you want to use yolks as a thickener agent for sauces, here is what you should do:

  • Grab one or two eggs (depending on the amount of sauce you want to prepare) and separate the yolk from the egg white. Place the yolks in a small bowl.
  • Add a few tablespoons of the warm sauce and whisk quickly to mix well. That will heat the egg yolks without curdling them.
  • Pour the mix into the sauce and stir. You will get a thick sauce in a few seconds.

Tomato paste

Tomato paste is the key to a thick, deep red-colored spaghetti sauce. It will add a dense consistency and a much richer, tomato-y taste for a full-flavored pasta dish. Yet, you have to make some adjustments and be careful not to make the sauce too heavy. After all, we still want our sauce to be liquid.

Whenever you use tomato paste to thicken a sauce, add small amounts gradually, tasting as you go. Remember that tomato paste is very thick and can change the texture of the sauce drastically. So, add one tablespoon at a time, stir, and check the consistency and flavor.

You will have to add a bit of sugar and salt to compensate for the strong flavor of the tomato paste. That is why you should go slowly, adjusting the seasoning as you add more paste (if necessary).

Mashed potatoes

Have you ever thought of using mashed potatoes as a thickener agent? Well, believe it or not, they are an excellent choice for getting a creamy texture in your sauces. That is because potatoes are full of starch, so they do an impressive job absorbing liquids. What’s more, they can also enhance the flavor of the sauce.

So, if you have some potatoes in the kitchen and want to get creative with your sauce-making process, here is what you should do:

  • Depending on the amount of sauce you want to prepare, grab one or two potatoes and boil them until they are tender.
  • Peel the potatoes after you boil them. That way, it will be easier to remove the skin.
  • Use a fork to mash the potatoes. And, if you want a creamier paste, you can add a bit of milk or butter to taste.
  • Add the mashed potatoes gradually to the sauce and stir until you get the desired thickness.

Mashed potatoes are great for making richer and thicker sauces, but they can change the taste of the original recipe, so you must adjust your seasoning if you want to tone down the potato flavor.

Nevertheless, if you are a potato lover, you will most likely enjoy that twist to the spaghetti sauce— more if you use sweet potatoes.

Adding vegetables

Another effective solution to fix runny sauces is to add vegetables, either grated or mashed.

You can use almost any vegetable you like: carrots, zucchini, onions, mushrooms, kabocha, and more. All these options work shredded, chopped into small pieces, or pureed.

Moreover, you can combine as many ingredients as you want to prepare a more filling sauce. And, for smoother results, you can also blend the sauce to avoid clumps.

Vegetables not only add texture and flavor to the sauce but also more nutrients. Plus, if you add them pureed, you can easily hide them for those who don’t like to eat whole veggies. That is a good trick for moms trying to get their kids to eat healthier (but, hey, it works for adults too!).

Wrap up

We all love a thick, flavorful, and deep red homemade spaghetti sauce, and with these tricks, you will never have to worry about runny sauces again.

Cornstarch and tomato paste are probably the most popular and beneficial choices for thickening sauces, but you can be creative and use mashed potatoes or vegetables for added flavor. Still, if you don’t have these ingredients in your pantry, simmering will always be the best alternative.

There are other ways to thicken spaghetti sauce (like adding cheese or breadcrumbs, for example). Yet, these seven methods provide the best results without altering the original recipe that much.

Now, are you ready to take your spaghetti sauce to the next level?

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