Many people use tomato paste or tomato puree to thicken their spaghetti sauce. But what happens if you are in the middle of making dinner and you realize you are out of that essential ingredient? Improvise!
The good news is that there are many different ways to quickly and effectively thicken spaghetti or marinara sauce without tomato paste. All you need to do is replace the paste with a thickening agent. One that you probably have lying around the kitchen already!
Why Does Spaghetti Sauce Get Watery?
The main culprit is tomatoes. When making spaghetti sauce, it is easy to go from a remarkable consistency to one that is too watery if you have extra plump tomatoes.
As tomatoes cook down, they release all of their wonderful juiciness but that goodness can also cause an imbalance. So, even if you’re using the same recipe as before, the thickness may vary depending on the tomatoes you use.
That’s why it’s good know different options to thicken your tomato sauce on the spot. Because you’ll never know when it won’t turn out as thick as you’d like.
The following outlines several ways to achieve the desired consistency of your fresh tomato sauce without changing the flavor of the dish!
How to Thicken Spaghetti Sauce without Paste
There are four broad categories or methods when it comes to thickening up a tomato sauce. You can reduce the liquid, add a starch, add a protein, or change the liquid-to-solid ratio.
Method #1: Extract Liquid

Using this type of method, you do not have to add an extra ingredient to your pasta sauce. Instead, you take away.
Option 1: Reduction
The easiest way to get rid of excess water in your homemade tomato sauce is to use the reduction method. Many think this is the best option since it only requires a heat source and no added ingredient. It will not change the taste of the sauce, or add unwanted ingredients to your favorite homemade spaghetti sauce.
Using this simple trick can reduce the amount of liquid, helping your sauce get to the right thickness. All you have to do is let the sauce simmer over low heat for about 20-30 minutes, and the excess liquid will boil off.
The “best” method: Simmer the sauce for 20-30 minutes to burn off the excess water.
If you don’t have 20-30 minutes to spare but still want to use this method, you can bring the heat up to medium and stir it frequently to help achieve thick sauce more quickly. Just be careful not to let it burn.
This is often touted as the best way to thicken your pasta sauce since you are not adding anything that could potentially alter the flavor of your sauce. You are simply extracting the water, reducing the amount of sauce in the pan. However, the best method certainly isn’t the quickest.
The following methods offer quicker solutions for thickening up that sauce.
Method #2: Add a Starch

You can also easily thicken spaghetti sauces by adding starch. This is an almost immediate solution, as you can simply pull the starch out of your pantry and mix it into your sauce.
Option 1: Add Cornstarch
Cornstarch is a go-to thickening agent, and a tablespoon of cornstarch can go a long way in thickening spaghetti sauce.
Starches consist of long chains of glucose molecules that plants use to store their energy. When heat is added to starches, it takes on a gelatinous quality, soaking up excess liquid in a solution. That is why starch molecules can thicken your watery tomato sauce effectively.
1:1 ratio of cornstarch to water
An easy way to use starch to thicken your watery sauce is by making a cornstarch slurry. To make the slurry, you will mix a 1:1 ratio of cornstarch to water. An easy way to start is to combine one tablespoon of starch and one tablespoon of water.
Then add the slurry 1 tsp at a time to your sauce. Stir it in well, then wait for one minute since corn starch takes a little time to break down. Repeat this procedure until you reach the desired consistency.
This technique will provide thick consistency without changing the color or flavor of your red sauce.
Option 2: Add Pasta Water
Another way to thicken watery spaghetti sauce is to use the starchy water that was used to boil your pasta. This works best when using a traditional, wheat pasta.
When you boil pasta, it releases a lot of starch into the surrounding water. Add a few spoonfuls of starchy water to thicken your sauce. Use water that had the cooked, or nearly cooked, pasta. Then wait a minute, and it will slowly thicken the sauce, much like it does when you add corn starch.
Adding a little water that you already have from your pasta can help give the sauce a thick texture without affecting its taste.
Option 3: Make a Roux
You can also thicken up thin spaghetti sauce by making a roux. A roux is a fancy name for a mixture of butter and plain flour and is a common option used to thicken all sorts of recipes.
Roux: a mixture of butter and flour.
To make a roux, cook equal parts of flour and butter over low heat. Once it simmers, add it to your sauce a spoonful at a time until you reach the desired consistency.
If you have the time, cook the sauce on low for an additional 20 minutes to rid the sauce of any “raw flour” taste.
Option 4: Add Mashed Potatoes
To thicken the texture of the runny spaghetti sauce you can add mashed potatoes, which are almost pure starch. This may sound crazy, but it works!
You can use leftover mashed potatoes, adding in a little bit at a time to your desired consistency.
Or, microwave a peeled potato until it is soft. Then mash it with a fork, adding one spoonful at a time to the thin sauce until it reaches the texture that you want.
Easier still, you can mix in a bit of dried, packaged mashed potato mix. If you’re making your own pasta sauce from scratch, you may not be the type to have packaged potatoes in your pantry. But hey, you never know.
Method #3: Add a Dairy Protein

This section includes ways that adding protein can help thicken up the watery sauce.
Option #1: Add in Egg Yolk
Another way to get thicker sauce is to add egg yolks, which also offer added health benefits. With this technique, you will need to first temper the yolk to avoid overcooking it.
Place 1 – 2 egg yolks in a bowl. Then whisk a little bit of hot pasta sauce into the egg.
After that is done, add the egg mixture to the rest of the sauce.
The great thing is that your egg will not alter the flavor of your sauce. Nor will it affect the appearance or texture of your sauce.
Just be mindful of the tempering process so that you don’t overcook your egg when you first add it to the sauce, which could alter the sauce flavor and texture.
Option #2: Mix in Cheese
You can also achieve thick spaghetti sauce by adding cheese. And many people add cheese anyway to pasta, so it is kind of a “win, win” situation!
Instead of putting parmesan cheese, or other cheese, on top of your pasta, you can throw it into the sauce as a thickening agent. Not only will it get your sauce to a more desired consistency, but it can also pack a punch of delicious flavor!
Cream cheese can make spaghetti sauce creamier and thus thicker, too. It’s not often used in traditional Italian dishes, but it’s not uncommon in American sauces, like American-style Alfredo.
If you’re going to try cream cheese, I suggest ladling out some of your sauce to make a little taste test sample. Then you can decide if you still like the flavor with this non-traditional addition before mixing it into your entire batch.
Method #4: Alter the Liquids-to-Solids Ratio

This final section includes ways to alter the liquid-to-solids ratio by adding various food items.
Option #1: Add Meat
The beautiful thing about pasta is you can successfully add virtually any meat to it. If your goal is to thicken the sauce, then ground beef or Italian sausage are perhaps the best options since they can easily be broken down into little bits. The little bits can be spread evenly to make the sauce thicker overall.
Other great meat options include smaller pieces of chicken, shrimp, lamb, pork… like I said, basically any meat. These additions tend to make the sauce chunkier more than thicker, but it achieves a similar goal. They’re more of a work-around since they don’t thicken the liquid but do make the sauce more substantial overall.
Option #2: Add Mashed Vegetables
Another thickening ingredient that can also add significant nutritional value are mashed vegetables. When you consider tomato paste, it really is only made from pureed tomatoes. Create a replacement puree by mashing up a different vegetable.
You can try cauliflower, squash, eggplant, or any other vegetable that pairs well with pasta.
Option #3: Add Bread Crumbs
Another great way to thicken your fresh tomato sauce is to use bread crumbs. Beware, however, that breadcrumbs can potentially alter the texture of the sauce. It can make it slightly chewier as it thickens.
Just like with the other techniques, add a small number of bread crumbs at a time to your sauce until it reaches the consistency that you are seeking.
Option #4: Blend/Puree Part of Sauce
A final way to thicken your pasta is to puree all or small amounts of the sauce. When you do, the solid parts of the sauce will break up and become much like the pureed vegetables mentioned in the previous technique.
Simply use a blender, immersion blender, or food processor to puree a little sauce at a time until you reach the desired thickness.
An immersion blender is the most suitable for this technique, but use whatever you have on hand!
2 Delicious Yet Easy Spaghetti Sauce Recipes

With all this talk of spaghetti sauce, I can’t help but provide a couple of great recipes. They each require several ingredients, but are very easy to make. In fact, they each only require 3 steps!
Spaghetti Sauce Recipe #1
Here is your first one-pan-wonder option. The green bell pepper adds a bit of bitterness that helps balance out the rest of the sauce.
Ingredients (8 servings)
- 1 onion, chopped
- 4 cloves garlic, minced
- 1 small green bell pepper, diced
- 1 (28 ounce) can diced tomatoes
- 1 (16 ounce) can tomato sauce
- 1 (6 ounce) can tomato paste
- 2 teaspoons dried oregano
- 2 teaspoons dried basil
- 1 teaspoon salt
- ½ teaspoon black pepper
Directions
- Combine onion, garlic, and green pepper in a large saucepan. Cook and stir until vegetables are tender.
- Stir diced tomatoes, tomato sauce, and tomato paste into the pan. Season with oregano, basil, salt, and pepper.
- Simmer spaghetti sauce for 1 hour, stirring occasionally.
Spaghetti Sauce Recipe #2
This recipe adds a bit more sweetness with just a spoonful of sugar. It’s another one-pan wonder that should please even picky eaters.
Ingredients (Serves 6)
- ¾ cup chopped onion
- 5 cloves garlic, minced
- ¼ cup olive oil
- 2 (28 ounce) cans whole peeled tomatoes
- 2 teaspoons salt
- 1 teaspoon white sugar
- 1 bay leaf
- 1 (6 ounce) can tomato paste
- ¾ teaspoon dried basil
- ½ teaspoon ground black pepper
Directions
- In a large saucepan over medium heat, saute onion and garlic in olive oil until onion is translucent.
- Stir in tomatoes, salt, sugar and bay leaf. Cover, reduce heat to low, and simmer 90 minutes.
- Stir in tomato paste, basil, 1/2 teaspoon pepper and meatballs and simmer 30 minutes more. Serve.
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As a mom of three little eaters, I am excited to share my love of cooking, smoking, and baking with you. My love of food started when I went to college in Berkeley, and has followed me ever since! When I am not “momming,” writing, or cooking, you can find me reading, traveling, or hiking.