Note: We Want The Sauce is reader supported. If you make a purchase through a link on our site, we may earn an affiliate commission - at no extra cost to you. This includes links to Amazon.

How To Thicken Marinara Sauce ⋆ 6 Solutions To Try ⋆

If you make or open a store-bought jar of marinara sauce and find out that it is diluted and watery. Do not throw it away! It can be rectified. Need to thicken it, but not sure what to add or how to do it? Take a deep breath and use one or more of the different ways to thicken it up that are listed below.

So, how do you thicken a marinara sauce? The best way to thicken a marinara sauce is to simply simmer the sauce over low to medium heat. You can also use other easily available pantry items like tomato paste, flour, thickening agents such as corn starch, tapioca starch, and even pureed vegetables. 

Despite our best efforts to make a lovely thick marinara sauce, sometimes it turns out thin and disappointing.

The method you choose is dependent upon the time you have as well as the ingredients in your kitchen cupboard, and your personal preferences too.

You might like to use one or a combination of these methods.

With all these useful suggestions, you can ensure your marinara sauce is thick, delicious, and not watery each time you make it.

Are you ready to read further and see how these options can work? But let’s first figure out why the marinara sauce is watery and thin? 

Why Is My Marinara Watery?

Marinara sauce can be watery due to the high moisture content of fresh tomatoes and the wrong technique to cook these tomatoes. Not cooking the sauce long enough can give you a thin sauce. Cooking the sauce with the lid on can also result in a watery sauce.

Using good quality, firm, meaty tomatoes is key here. But sometimes it is best to use canned tomatoes if you think the fresh tomatoes are not great.

If using canned tomatoes, they contain quite a bit of water in addition to the liquid in the can. As the tomatoes cook, they release more liquid and can make your marinara watery.

For the marinara sauce, you must pay close attention to the cooking time and temperature.

Let the sauce simmer on low heat for a good amount of time. You might be tempted to stir it frequently but don’t. Just leave it alone for some time.

The marinara sauce needs to come to a boil and then be simmered till it reaches its desired consistency.

If using a roux to thicken, do not cook it till the brown stage as it loses some of its thickening power resulting in a watery sauce.

How Thick Should A Marinara Sauce Be?

A perfect marinara sauce needs to have a little bit of texture. It shouldn’t be too smooth and neither too chunky. Marinara, unlike tomato sauce, is light, thin, and full of flavor and usually cooks in under an hour.

But, how do you know if it’s thick enough? You can use this simple spoon test to check.

Place a spoon into your sauce and take it out again. If the spoon is coated, it should be thick enough. 

Alternatively, another great way to know that your sauce has reached your desired consistency, you can run a spoon across the pan at the start of cooking.

Again, you should notice the ingredients close together over the path of where you ran the spoon.

As the sauce begins to thicken, you should see the line in the pan, as if you are drawing it. This line takes longer to fade as the sauce thickens.

I recommend you to hand-crush your tomatoes with the back of your wooden spoon before starting to cook the sauce.

If you would rather have a smoother sauce, you can just pulse the tomatoes once the sauce has finished cooking and then adjust for the thickness required.

What Can You Use To Thicken Marinara Sauce?

If your marinara sauce is watery, you can thicken in two ways– firstly, by reducing to boil off the excess liquid and secondly, by adding a thickening agent – like tomato paste, starch, roux, boiled pasta water, pureed/ mashed vegetables.

You simply don’t have to serve a weak sauce.

Thickening a marinara sauce is easy and can prevent you from tossing a thin, runny product in the garbage.

How To Thicken Marinara Sauce – Step by Step

Below I will run through the best methods you can use. 

Each method has its own advantages and disadvantages, and most of the time, you might use a combination of methods in tandem that best suits your needs.     

Thickening By Reducing

Reduction works particularly well for tomato-based sauces because added starches sometimes interfere with the acid in tomatoes.

Simmering the sauce for a longer period will help eliminate some of the excess water.

As the water evaporates, the natural sugars are released and caramelized during this process; it leaves behind a thick, full-bodied, and full-flavored sauce.

This is a great solution if you do not have other ingredients or equipment on hand. 

But this process is time-consuming, so if you are in a rush, I suggest you use other options.

The steps are: 

  1. Simmering– By simmering over a low heat, the liquid in the sauce will evaporate, and naturally it will thicken. Just be sure that the sauce remains at a low heat while it simmers.
  2. Heating – The sauce should come to a boil and then be simmered. Also, the high heat can result in the burning of the sauce.
  3. Stirring – Occasionally stir the sauce with a wooden spoon to avoid scorching  
  4. Testing the thickness -The time required for the sauce to thicken is determined by the quantity and one’s preferences. It usually takes 10- 60 minutes.

You can remove the sauce from the stove when you are happy with the consistency. The sauce will thicken more upon cooling.

Thickening With Tomato Paste 

This is a no-brainer and one of the simplest methods to thicken your marinara sauce. This method will help you retain the same appeal and flavor. This is what you need to do:

  1. Open the can of Tomato paste
  2. Add about 2 tablespoons of tomato paste or more depending upon the quantity of the sauce
  3. Stir and cook for 5 minutes till you achieve the desired thickness.

When you add the thick tomato paste to your sauce, you increase the amount of tomato solids without adding more liquid, therefore thickening the sauce.

Thickening With Starch

Cornstarch is commonly found at home and is a great thickening agent.

The liquid thickens because of gelatinization. The starch molecules swell and absorb excess water from the sauce. 

It is flavorless, so it does not alter the appearance or taste of the sauce.

You must avoid adding it directly to the sauce as it can result in clumping.

Cornstarch, when made into a slurry, eliminates clumping. The steps are described under.

  1. Whisk a 1:1 ratio of cornstarch and liquid (cold water or milk) in a bowl to make a slurry.
  2. Add this slurry into your sauce while stirring.
  3. Let the sauce simmer with occasional stirring under low heat to eliminate the starchy taste.

You need to adjust your salt and seasoning when you use starches, as they tend to mask the flavors.

Start with a little starch, to begin with. Else your sauce can turn lumpy. You can use any starch of your choice- potato starch, tapioca starch, arrowroot, etc.

Thickening With Roux

All-purpose flour is a readily available thickener in most kitchens.

Making a roux (a mixture of equal parts of flour and butter) is one of the most common ways experienced chefs use for thickening. Roux can be prepared in the following way:

  1. Heat butter in a pan over low heat and add an equal amount of flour.
  2. Cook the roux, constantly whisking till it smells nutty. If it starts to brown, reduce the heat.
  3. Add about 1 tablespoon to the sauce and stir until combined.  
  4. Cook with frequent stirring until the consistency becomes visibly thicker. 

In this method, the flour is cooked in the ‘roux making process’ and does not give a ‘raw floury’ taste. It also imparts a creamy texture and rich flavor.

Thickening With Boiled Pasta Water

Pasta water can serve as an excellent thickening agent.

If you have pasta boiling around the same time, drain after it’s cooked and reserve the water for your sauce. When pasta is boiled, starch is released into the water. You can use pasta water in the following manner:

  1. Add up to ¼ – ½ cup of pasta water to your sauce.
  2. Initially, you will notice that the sauce is a little watery, but upon stirring, it will thicken.
  3. Continue to simmer on low heat until you are happy with the consistency.

You should not add pasta water to the sauce if it is already too thin.

Instead, you will want to use the pasta water instead of the water you would normally use in the recipe.

This method will also improve the flavor of the sauce.

Thickening With Pureed/ Mashed Vegetables

Adding pureed starchy vegetables like potato, cauliflower, and carrots to the sauce works like a charm to bulk it up. You can see the steps below:

  1. Boil the vegetable in a pan. Let them cool.
  2. Puree/ mash the vegetable. 
  3. Stir the puree/ mashed vegetable in the sauce, and the sauce will thicken quite a bit when it is simmered.

The sauce will also have a unique flavor with the addition of the mashed/ pureed vegetables.

Other Suggestions To Avoid A Watery Marinara Sauce

If the Marinara sauce isn’t thick enough, do not worry. Just check if you are following the recipe accurately. It does take some practice to master the sauce making.

When you start making the sauce, you must first bring the sauce to a boil before it is simmered. 

This is essential because fresh tomatoes contain natural enzymes which will break down the pectin. 

By heating rapidly to a boil, the enzymes are deactivated and prevent the sauce from turning watery.

If you’re running low on time and don’t need the sauce urgently, you can always cook the marinara sauce but then complete the reduction process the next day.

Try using a wider pot like a saucepan or a sauté pan to reduce your sauce. 

This will increase the surface area and thereby decreasing the reduction time and giving a uniform consistency.

For a perfect marinara, you can even use a slow cooker or a crockpot so that you don’t have to keep watching the sauce.

And with all the above go-to methods, we have discussed

A little patience is all it takes….


Making your own marinara is super rewarding, as it’s comforting and flavorful.

While it is simple and quick, it can be turn out watery at times.

You can easily remedy a thin sauce with any of the above hacks, depending on the time and availability of ingredients.

Try thickening that marinara sauce like a Pro! And you will never toss that watery sauce in the garbage again.

And every single time, you will have a sauce that will cling perfectly to your pasta, meat, or vegetables!

Want to learn how to thicken any type of sauce? Then check out my definitive guide: