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Watery Tomato Pasta Sauce? How To Thicken

Have you cooked up some pasta sauce and, ahead of serving, noticed it’s too watery? At least, it just won’t make that meal you were looking for and have come to expect from your culinary skills. Well, thankfully, with a few minor changes, you can get that sauce as thick as you need it to be to coat the pasta and give the texture you are looking for.

So, how do you thicken watery tomato pasta sauce? You can thicken watery tomato pasta sauce by either adding more tomatoes/tomato paste or by reducing it further over low heat (to evaporate some of the water). If you don’t mind altering the taste and texture, you could add a thickening agent (like tapioca/corn starch) instead.

Of course, it always helps to understand why your tomato pasta sauce is too watery, to begin with.

That way, you can at least understand how you got here and, in a similar vein, prevent it from happening again in the future.

So let’s now do that before turning to those solutions in further detail.

Why Is Your Tomato Pasta Sauce Watery?

There are three likely and potential reasons why your tomato pasta sauce is too watery; you have used a type/brand or can of tomatoes that naturally contain a lot of water, you haven’t cooked the sauce for long enough, or you didn’t drain the pasta sufficiently before combining.

Choice Of Tomatoes

Some tomatoes are naturally more watery than others.

A prime example would be chopped tomatoes compared to passata or plum tomatoes.

Some tomatoes are even naturally juicier than others (if you have made your own sauce from scratch).

Thus it could just be that a simple change in the type or brand of tomatoes you use (or if you were to put them through a sieve first) that you reduce the water content ahead of cooking sufficiently to the point where it does not become an issue later.

Not Enough Reduction

A great means of taking off excess water is to simply cook it for longer.

Thus, it could very well be that you didn’t cook the sauce for long enough or give enough time for the heat to evaporate the excess water.

Didn’t Drain The Pasta Enough

This typically happens toward the end, but it could be that when you drained the pasta, you left excess water.

Then, when you combined the pasta/sauce together, the water simply dropped to the bottom when it settled.

How To Thicken Watery Tomato Pasta Sauce?

You can thicken watery tomato sauce with four simple methods; either by passing the sauce through a strainer/sieve, adding more tomatoes/paste, reducing the sauce for longer, or adding a thickening agent. 

Pass The Sauce Through A Strainer/Sieve 

Firstly, a simple and effective strategy is to pass the sauce through a strainer/sieve.

This tends to work best if you are yet to combine your sauce with your pasta. Or it’s still in the pan, and you are running out of time.

Adding More Tomatoes/Paste

This can be a great solution, so long as you don’t inadvertently add more water in the process.

As such, you want to stick with tomatoes/types that do not contain much. Concentrated options such as tomato paste are ideal here.

You will likely need to reheat or continue cooking the sauce with this method, as you will naturally reduce the temperature anytime new ingredient(s) are added.

Reduce Further

This option requires time, but it doesn’t require anything else (whether that be utensils/equipment or ingredients).

All you need to do here is keep simmering the sauce – giving more time for the water to boil off.

A good way to do this is to first bring the sauce to a fast boil, then drop the heat down low.

Adding a lid to the pan can also help retain the heat here too during the initial boiling (though be sure to remove it when it comes time to simmer).

Generally, the longer you let the sauce simmer, the thicker it will become.

Equally, if you use a wider pan, you should notice that the sauce reduces faster.

You should, however, stand over the sauce and keep stirring it to ensure the sauce doesn’t burn.

Add A Thickening Agent

First and foremost, a word of warning. Doing this can alter the flavor/texture of the sauce.

Get it wrong, and you can also end up with a grainy sauce… not good!

Nevertheless, there are quite a few thickening agents you could use here; cornstarch, tapioca starch, potato starch, and arrowroot starch, among a few others (e.g., rice flour.)

Regardless of what you use, the process is still relatively similar – making a slurry in a separate container first.

All you need to do is add/and mix equal parts water with the thickening agent of choice.

Ensure the starch has been completely dissolved, and then add a small amount of this slurry to your sauce.

Less is more here.

You can always add more as you go, but you cannot remove it.

So be mindful.

And a little goes a long way.

Just be sure to stir the sauce as you add the slurry to ensure it evenly distributes.

So if you go this route, remember this.

Add a small amount, stir, give the sauce a few minutes, check the consistency, and repeat (if required).

Why Is My Tomato Sauce Not Thickening?

Okay, so let’s quickly run through a few potential reasons why the solutions presented above may not work out as expected or if you are just struggling to get your sauce to thicken.

Not Enough Time

I’ve mentioned this a few times, but I cannot stress it enough.

If you do not allow enough time for the sauce to cook or simmer, it’s going to end up being too watery.

Adding More Water

You could be inadvertently adding more water during the ‘thickening process.’

It could be by adding more tomatoes when you combine the pasta and sauce together (with insufficient pasta drainage), or it could be an inappropriately mixed thickening agent slurry.


So there you have it.

Various options to try.

It ultimately comes down to a few things.

Time, ingredients to hand, and the stage of cooking you find yourself in.

Hopefully, I have covered the bases regardless of where you find yourself; either before you have even cooked the sauce or even after plating!

Related Questions

What can I use to thicken tomato pasta sauce?

You can use more tomatoes, tomato paste, or thickening agents to thicken a tomato pasta sauce. Cornstarch, potato starch, tapioca starch are all good options for the latter.

Related guides you may want to check out:

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