American sauces are a nightmare to get right. With traditional French or Italian or even English cooking, it’s pretty easy to find a single, reliable source you can use for your recipe. This lets you quickly compare the dish you’ve made with an “ideal” version and make the appropriate changes. When you ask a friend for advice or look online, you can usually get a pretty definitive answer immediately. If you need to thicken a pasta sauce, there will be a note in the recipe that tells you exactly how to do that.
American dishes do not work this way. You’ve probably run into this problem if you’ve ever tried to re-create your favorite ranch or barbecue sauce. Each state has its own regional variations on these sauces, and each city within that state might vary the recipe even further. What might be hailed as “correct” in some parts of the country would be rejected based on texture alone in others without so much as a whiff.
Spaghetti sauce is in a very similar boat. This quintessential American sauce has little to do with its original Italian marinara roots. Instead, it’s a totally customized recipe that varies quite a bit depending on whose kitchen you’re in.
Because of this, it can be pretty tricky to get spaghetti sauce to have the consistency you want. Here are some tricks you can use to get your sauce to come out the way you want it.
How To Get Sauce To Thicken — General Tips
In general, there are two ways to thicken sauce: add starch and reduce liquid.
These two actions pretty much cover every thickening technique you can think of. Reducing the liquid can be done by either simply adding less to begin with, adding thicker liquid (milk instead of water, for example), or boiling off liquid over time. Starches include cornstarch, flour (often found in a roux), breadcrumbs, pasta water, or even mashed potatoes.
Most of the time you’ll do these actions somewhat in tandem. You usually want to cook any starches you add for a little bit to reduce their starchy flavors. It’s also easier to dissolve powders (or solids) in hot liquid. Because of this, you’ll usually boil off a little bit of liquid while you incorporate your starch.
When you’re trying to thicken up spaghetti sauce, one additional option exists. Tomato paste is a fairly thick tomato-based flavor additive that helps to make your sauce thicker. This is because it’s basically thick tomato sauce already. When you add it to your spaghetti sauce, you’re increasing the amount of tomato solids without increasing the amount of liquid by as much, therefore thickening the sauce.
How To Thicken Spaghetti Sauce Without Tomato Paste
Spaghetti sauce isn’t hugely different from any other sauce with regards to basic thickening principles. Here are some specific techniques you can use to thicken it without resorting to tomato paste.
1. Reserve pasta water and use it for sauce
Water that you’ve cooked pasta in has lots of starches floating around in it. This makes it a remarkably powerful thickening agent. You don’t necessarily want to add it to sauce that’s already too thin. Instead, use a bit of pasta water as the water you use in your recipe.
2. Add cornstarch
Cornstarch is pretty flavor neutral and very easy to add to a sauce that’s already been made. You don’t need to make a roux or mix it with anything. Instead, simply stir in a small amount of cornstarch and let it cook for a minute or two. You’ll often see results with a shockingly small amount of cornstarch.
3. Make A Roux
A roux is a combination of flour and fat that’s been cooked for a little bit. While it takes a bit of effort to mix butter and flour and cook them until it stops tasting flour-ey, making a roux is one of the most common ways an experienced chef will thicken pizza sauce. You can do this very quickly with a bit of practice.
4. Add Mashed Potatoes
This one sounds a bit crazy, but it totally works. Just like pasta, cornstarch, and flour, potatoes are loaded with starch. If you’ve got a cooked potato lying around, try mashing it up and blending it into your sauce. You’ll get a bit of a unique flavor and you’ll thicken your sauce up quite a bit.
5. Reduce Your Sauce Through Cooking
No matter what other techniques you use to thicken marinara sauce, you’ll want to also use this one. Letting your sauce simmer over low heat for several minutes will cause lots of water to evaporate through the normal boiling process. You’ll also help blend the herbs and spices in the sauce together, activate any starches you’ve added, and cook off any starchy flavors. You don’t have to go too crazy with cook times. 20 minutes is usually plenty.
Reducing Sauce Like A Pro
There’s a simple trick that can make the reduction process go by much more quickly. Instead of turning the heat up or waiting for a long time for your sauce to reduce, try using a wider pot or even a pan. The surface area of your sauce has quite a lot to do with how fast it will reduce and thicken up when you leave it at a simmer. Ideally, you’d use a saucier pan or another fancy pan with sloped sides, but it’s totally fine to just use a larger stockpot, a saute pan, or even a frying pan. As long as you increase the surface area of your sauce, the time it takes to reduce will go down.
Does Spaghetti Sauce Even Need To Be Thick?
Traditional marinara sauce is actually quite thin. The thick, meaty spaghetti sauce you’re probably familiar with is very much a modern American invention. If you prefer your sauce this way, there’s certainly nothing wrong with thickening things up and adding lots of hearty ingredients to your spaghetti sauce. On the other hand, there’s nothing wrong with enjoying a thin, flavorful tomato sauce either! Feel free to experiment with both styles in order to find out what works best for your own taste buds.
The Best Way To Thicken Spaghetti Sauce
A simple combination of all of the techniques above will work wonders to thicken your spaghetti sauce and save your dinner. First, add a very small amount of starch, like cornstarch or a roux. Next, add a little bit of tomato paste to thicken things up more and improve the flavor. Finally, stir your sauce and simmer it for at least 10 minutes. In most cases, this will give you a very thick spaghetti sauce that will impress your guests.
If this doesn’t work perfectly the first time, simply repeat the steps! Be sure to taste your sauce as you go, however. While some starches (like cornstarch) are nearly flavorless in small quantities, you’ll eventually be able to taste them if you add enough to your sauce. If you find yourself going overboard, you may want to add more spices, garlic, or even tomatoes to help reset the balance.
Luisa Davis is a frelance writer and foodie based in Portland, California. Though raised on her mother's homestyle Italian cooking, she has spent most of the last five years traveling and immersing herself in other countries' cuisines. Her work have been published in various publications, both online and offline.