I Tried 7 Ways to Thicken Soup and the Winner Won By a Landslide

published Jan 24, 2024
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Credit: Photos: Alex Lepe; Design: The Kitchn

Is soup the perfect meal? With endless varieties, there is literally a soup for every mood, ingredient combination, time constraint, and dietary need. Some days, you want to sip on lots of flavorful light broth studded with just a few ingredients. On other days, only a thick and hearty soup will do — the kind that is closer to a stew, where rich broth blankets and coats an abundant amount of “stuff.” 

So what happens when you want the thick and hearty kind but find yourself with the light and brothy kind? Knowing how to quickly thicken soup that is more watery than desired is a pro move in the kitchen, but with so many options and opinions for how to do this, it’s not always clear which route to go.

To test out the best methods to thicken soup, I read up and researched various tips and articles to gather seven top recommendations to try. I settled on a classic and simple chicken and rice soup for the base, opting for more broth instead of half-and-half in the last few minutes, as dairy can have its own thickening properties.

During testing, I quickly realized that almost every method altered the flavor and color of the soup in addition to the viscosity. It made the ranking a little tricky, as there will be some personal preferences or dietary restrictions that could affect which method to choose. I noted in each how deeply the flavor changed and weighed the balance of thickening power with the flavor and texture changes to settle on the ratings. While the overall winner didn’t surprise me, the varied success among methods certainly did!

Quick Overview

So, What Is the Best Way to Thicken Soup?

Whisking beurre manié (butter-flour paste) into simmering soup is the best way to thicken an otherwise too-watery soup. Add bits of the paste gradually and simmer to cook out any raw flour taste. The broth will be velvety smooth, rich, and thick. 

How I Found the Best Way to Thicken Soup

  • The soup: To ensure the base of the soup was the same for each test, I cooked a pot of plain long-grain white rice and poached enough chicken breasts for all the soup I needed the day before starting. The rice and chicken were cooled, packed in separate containers, and stored in the refrigerator. I made two batches of soup using the same ingredients in each. I replaced the half-and-half with more broth for a neutral, transparent soup that would make thickening changes easy to see and taste. Lastly, I added only half the rice called for in the recipe so the soup didn’t feel overly loaded or thick from the start.
  • The testing: For each test, I transferred about 2 cups of freshly made soup into a small pot and returned it to a simmer over medium heat. I then gradually added the thickener, simmering or boiling if needed, until the texture changed. The one exception was the beaten egg, which needed its own method. I let all the soups cool just long enough that I didn’t scald my taste buds and then tasted each one immediately (as thickeners will continue to change the texture as they cool).
  • Ratings: I judged each method on a scale of 1 to 10, with 10 representing a delicious, perfectly thickened soup. I considered how the thickening element changed the texture, aroma, and taste. Most importantly, was the thickening addition worth the changes it brought with it?
Credit: Photo: Alex Lepe; Food Stylist: Brett Regot

Soup Thickening Method: Egg

Rating: 1/10

About this method: Eggs are a common way to cook liquids into silky, thick sauces and custards. Pastry cream, ice cream bases, and crème anglaise all rely on gently cooked eggs for their texture. So I figured, why not treat eggs the same way to thicken soup? 

To avoid creating egg drop soup, as tasty as that is, I beat a large egg in a small bowl until well combined and then, while whisking, poured in about a half cup of hot soup. I reduced the heat under the soup until it was steaming but not simmering, and then I poured the egg mixture back into the soup. I cooked, stirring, until the edges of the soup started bubbling and the texture changed inside the pot.

Results: I still ended up with a mixture that looked like egg drop soup. After initially adding the egg mixture, the soup looked creamy and smooth but was not thickened at all. I continued to cook, stirring, and after a few minutes, the egg separated from the broth and curdled into little bits even though the soup hadn’t boiled. 

Although it didn’t change the flavor of the soup, and the little egg bits had a soft, almost imperceptible texture when eating, I have to give this method a low rating. In addition to being the most technical of the bunch, it did not deliver any thickening power.

Credit: Photo: Alex Lepe; Food Stylist: Brett Regot

Soup Thickening Method: Blended Tortilla

Rating: 2/10

About this method: Flour tortillas are absorbent and fairly neutral in flavor, so when I came across it during my research as a way to thicken soup, it made perfect sense. Because this soup is chunky, I blended the tortilla before adding it so it would integrate more seamlessly. I tore up a large flour tortilla and softened it with a splash of water before blending it into a very thick, smooth paste. I added the paste gradually while simmering until I noticed the texture change.

Results: When adding the tortilla paste, the broth turned a creamy color right away, and the smell of tortilla wafted from the pot, but it did not thicken. I needed to add the entire batch of soft taco-sized tortilla puree into the small pot of soup before the broth thickened at all. 

When it did thicken, it maintained a creamy look, but the texture was slightly gelatinous. Even though the tortilla was blended smooth, as it simmered, little balls of tortilla formed in the broth. On the plus side, neither the aroma nor the tortilla specks translated into a strong tortilla taste, but the texture was slippery, and somehow, despite the gelling, the soup still wasn’t thickened much. This method just didn’t prove beneficial in any aspect.

Credit: Photo: Alex Lepe; Food Stylist: Brett Regot

Soup Thickening Method: Blended Slice White Bread

Rating: 4/10

About this method: From binding meatballs to creating a thick and hearty classic Italian soup, bread is a multi-purpose ingredient. Using a slice of bread to thicken soup was listed over and over during my research. 

To test it out, I tore up a slice of white sandwich bread and added just enough liquid to blend it into a thick paste. Similar to the tortilla test, I wanted to add the bread already in a smooth form for easier thickening and without any large chunks floating in the soup. I added the paste gradually, simmering until thickened.

Results: Even though the bread had been blended smoothly, once it was added to the soup and simmered, it hydrated into little bits and strands, giving the broth a cloudy, curdled appearance. The soup did thicken slightly, but it took an entire slice to make any impact, and the final result was a liquid with some extra body and heft, but ultimately still thinner than desired. 

In regards to flavor, the little strands of bread didn’t have a particularly strong taste, but the whole batch of soup did have a bready, heavy flavor that took away the freshness of the original recipe. This would be a good option for someone who wants to use up a bit of extra bread and isn’t looking for a strongly thickened finished result.

Credit: Photo: Alex Lepe; Food Stylist: Brett Regot

Soup Thickening Method: Blended White Beans

Rating: 5/10

About this method: Beans are nutritious, pantry-friendly, and super common in soup anyway, so trying them out as a soup thickener was a natural fit. To minimize bean flavor, I opted not to use the bean liquid. I drained and rinsed canned white beans and then blended them without any additional liquid until smooth. I added gradually to the simmering soup until I saw the texture change.

Results: It took quite a bit of the beans to change the texture of the soup, and even then, the thickening power was subtle. Similar to the version with bread, the broth took on body but didn’t feel heavily thickened. 

Unlike bread, the bean flavor was strong. Did it taste bad? No! The beans added a lovey creamy flavor and smooth texture that was not gritty or mealy. It changed the soup from a simple chicken and rice soup to a bean, chicken, and rice soup, which is just different. It didn’t feel out of place in the soup, but the flavor might not be for everyone — especially for someone wanting a very thick soup, which would require a hefty dose of beans.

Credit: Photo: Alex Lepe; Food Stylist: Brett Regot

Soup Thickening Method: Instant Potatoes

Rating: 8/10

About this method: Instant potatoes are shelf-stable cooked and dehydrated potatoes broken down into thin small bits or a nubbly powder. They can be purchased plain or in a wide variety of flavors (check out these top picks). Potatoes, in general, are a great way to create a thick soup, like this creamy chicken potato soup, but because they need time to cook before they can thicken, they aren’t a great option to thicken a soup that is otherwise ready to eat. 

To test the instant potatoes, I added them one tablespoon at a time to the simmering soup until the broth was thickened. I let each addition simmer for a minute or two to allow the potatoes to fully hydrate before adding more. This was by far the easiest and least technical of the bunch.  

Results: I was very unsure which way this test was going to go. Would the soup be floury, starchy, or grainy? Would the potatoes end up over-hydrating and make the soup too thick? I was pleasantly surprised that none of these were true. The soup was very smooth, pleasantly thick, and had a richness that made it taste like a heavy glug of cream had been added instead of potato. 

The only potential drawback is that it definitely made it taste like a potato-based soup. As a staunch potato-lover, that’s OK with me, but if you wanted it to be closer to the original, this might not be the winner for you. However, due to ease of use and overall texture, it still gets a high ranking.

Credit: Photo: Alex Lepe; Food Stylist: Brett Regot

 Soup Thickening Method: Cornstarch Slurry

Rating: 8/10

About this method: One of the most common ways to thicken sauces and soups is with a starch-based slurry, and cornstarch is a popular choice. Cornstarch is flavorless, easy to mix up, and versatile, which makes it a go-to pantry ingredient. 

I made a classic slurry by whisking cornstarch and hot broth until smooth in a small bowl. I drizzled it into the soup gradually, and brought it to a boil to fully activate, thicken, and cook out the starch flavor before adding more. It is important to dissolve the cornstarch first, sd sprinkling it directly into hot soup would create hard lumps of starch, and to add it gradually as cornstarch is a powerful thickener. 
 
Results: This was the only method to not turn the broth a creamy opaque color, although it did become cloudy and somewhat murky. Simmering the cornstarch eliminated any additional flavors, so the taste of the soup was unchanged. The texture is the one dicey aspect of this method. The nature of cornstarch creates a slick, gelled consistency as it thickens. You have to hit the sweet spot of adding just enough to thicken but not so much that it becomes gloopy. 

As I added the slurry, the texture changes happened quickly. I felt gentle resistance around my spatula as I stirred, and the broth stopped sloshing around the pot and moved as one cohesive, thick liquid. The broth feels slippery in your mouth as you eat, which is not unpleasant, but it isn’t subtle either. As long as you don’t mind the texture of cornstarch, this is a great option. Overall, this gets a high rating due to ease, fast and strong thickening power, and neutral flavor.

Credit: Photo: Alex Lepe; Food Stylist: Brett Regot

Soup Thickening Method: Beurre Manié (butter-flour paste)

Rating: 9/10

About this method: Beurre manié is similar to a roux, as both are a combination of butter and flour used as a thickener. But a roux is used at the beginning of the cooking process, while a beurre manié is added at the end. 

I made a classic beurre manié by working equal parts softened unsalted butter and all-purpose flour together with a fork to make a smooth paste. I added nuggets of the paste gradually to the hot soup and brought it to a boil to cook out the flour taste and fully thicken the soup.
 
Results: It was very delicious. I smelled the butter, BUT it was not an overwhelming flavor. There was an extra richness and subtle “sweet cream” taste to the broth, even though I did not need to add much of the butter paste. The broth quickly transformed into a thick and creamy liquid that still tasted very much like the base recipe. 

There was no gelled or slippery feel, as with cornstarch, and it thickened more gently, leaving some room for error when adding the paste. When researching, I read that some people felt that adding flour could deaden or hide flavors in the base soup. While I did not find I needed to add so much that this happened, it did alter the flavor (as almost every method did), but I found the changes pleasant and mild. 

The beurre manié did add dairy and gluten to a soup that otherwise does not have either, but if there are no dietary restrictions, the flavor and velvety texture of the thickened soup outweighed any negative aspects and easily made this the top choice.

Overall Key Takeaways

Thickening soup can be achieved in a variety of ways depending on how much you want to thicken it and what additional flavors or textures you like. Several subpar methods didn’t work well to thicken soup at all, but there were also some with more moderate success. Beans and instant potatoes are great plant-based and pantry-friendly choices if you like the taste of those ingredients. A cornstarch slurry will also get the job done quickly, although it does add a unique texture. 

The best method to thicken soup is by stirring in a beurre manié at the end. The soup becomes velvety thick and takes on a subtle but delicious hint of rich butter. Beurre manié can be made ahead of time and stored in a container or sealed bag in the refrigerator so it’s ready to use in a flash.