Tomato paste is a thick, concentrated sauce made from cooked tomatoes. It packs a hearty tomato flavor and bright red color into a small amount of paste. Tomato paste is a pantry staple used to make sauces, stews, chilis, and soups. One of the main reasons cooks use tomato paste is to thicken and add body to recipes. But does tomato paste really thicken soup? Let’s take a closer look.
How Tomato Paste Is Made
To understand how tomato paste can thicken soup, it helps to know how tomato paste itself is produced. Tomato paste starts out as ripe tomatoes that are washed, crushed, and cooked down to remove excess water content. The tomatoes are then put through a finisher to separate out the seeds and skins. What remains is a thick, red tomato puree.
The tomato puree is then cooked slowly for hours to evaporate more water. As the water cooks off, the tomato solids become more concentrated. The puree goes from a thin, Runny liquid to a thick, rich concentrate. Cooking time can vary from 2-6 hours depending on the desired consistency. The end result is a deep red paste that is thick enough to hold its shape when canned.
Tomato Paste Nutrition
So what exactly is in tomato paste that helps thicken soup? Here is the nutrition breakdown for a typical 100g serving of tomato paste:
The main thickening agents in tomato paste are starch, fiber, and natural tomato pectin.
Tomato paste contains a high concentration of starch from the cooked tomato puree. Starches are long chains of glucose molecules that add texture and viscosity. As starch heats up in liquid, it swells with water absorption, causing the liquid to thicken.
There is also a significant amount of dietary fiber in tomato paste – 10g per 100g serving. Sources of fiber include tomato skins and seeds. Fiber helps trap moisture and increase the viscosity of soups and sauces.
Finally, tomato paste provides pectin, a form of soluble fiber. Tomatoes naturally contain pectin, which helps gives structure to plant cell walls. As tomato paste is cooked down, the pectin becomes concentrated. This pectin dissolves into soups and sauces, adding body and thickness.
How Much Tomato Paste To Use
When adding tomato paste to soup, the goal is to strike a balance – enough to add flavor and thickness without making the soup taste too strongly of tomato. Here are some general tomato paste guidelines per 1 cup of soup or sauce:
- 1 tsp tomato paste = Mild tomato flavor and light thickening
- 1 Tbsp tomato paste = Medium tomato flavor and moderate thickening
- 2 Tbsp tomato paste = Robust tomato flavor and significant thickening
For most soups, 1-2 Tbsp (15-30g) of tomato paste per cup of liquid is sufficient. Start with less and add more as needed. You can always add another spoonful to reach the desired consistency.
Thickening Soups Step-By-Step
Here is a simple step-by-step process for thickening soup with tomato paste:
- Make a smooth roux – Whisk together tomato paste and melted butter in a saucepan until fully combined and smooth.
- Gradually whisk in liquid – Slowly pour in small amounts of broth or water while continuously stirring.
- Simmer the soup – Bring the soup to a gentle boil, then reduce to a simmer. Let simmer for 10-15 minutes to allow flavors to meld and soup to thicken.
- Add more as needed – For thicker soup, stir in additional teaspoons of tomato paste until desired consistency is reached.
- Finish with cream (optional) – For an extra silky texture, stir in a splash of cream at the end.
The roux technique coats the starch and fibers in fat so they evenly distribute into the soup without clumping. Gentle simmering allows the tomato paste to further swell and thicken the broth.
Soup Thickening Science
Let’s take a closer look at the science behind how tomato paste is able to thicken and add body to soups:
When tomato paste is heated, the starch granules absorb water and swell up. This process is known as gelatinization. The swollen starch increases viscosity and gives the liquid a thicker, more cohesive texture.
Fiber and pectin require hydration to have a thickening effect. As tomato paste simmers in the soup, the fiber and pectin absorb and trap moisture. This increases the overall viscosity while giving a smooth mouthfeel.
The fat from the butter or oil in the roux helps emulsify the tomato paste. This allows the starch, fiber, and pectin to evenly disperse through the soup rather than clump together. Emulsifiers bind water and oil to create a uniform texture.
Tomato paste adds soluble solids to the soup which increases the overall density. More density means less wateriness and a thicker consistency. The concentrated tomato paste effectively bulks up the liquid.
Soup Thickening Troubleshooting
While tomato paste typically thickens soup nicely, here are some potential issues and how to avoid them:
Soup is too thin
– Add more tomato paste in teaspoons until desired consistency
– Make a second roux if needed
– Finish with a dash of cream
Soup has clumps
– Make sure tomato paste is fully incorporated into roux
– Strain soup if clumps are from skins/seeds
– Use immersion blender to puree soup smooth
Soup is too thick
– Add more broth or water to thin out
– Add cream or milk to thin and make silkier
Soup tastes too tomato-y
– Use less tomato paste next time
– Brighten flavor with lemon juice or vinegar
– Add more aromatic spices and herbs
Soup separates or curdles
– Don’t let soup boil rapidly after adding tomato paste
– Remove from heat and use immersion blender to emulsify
Thickening Soups Without Tomato Paste
In some cases, tomato paste may not be the ideal soup thickener. Here are a few tomato-free alternatives:
A classic roux made with butter and flour quickly thickens soups. The raw flour taste dissipates with prolonged simmering.
Mix cornstarch with cool broth until smooth, then stir into hot soup. Bring to a simmer until thickened.
For a fresh, light thickness, puree cooked potatoes, carrots, or cauliflower into the soup.
Cream and Milk
Stir in heavy cream, evaporated milk, or coconut milk at the end for instant richness.
Beans and Legumes
Pureed white beans, chickpeas, or lentils add natural thickness without detectable flavor.
Just a pinch of this powerful thickener makes soup nice and thick. A little goes a long way.
So back to our original question – does tomato paste thicken soup? The answer is a definitive yes! Tomato paste contains three key ingredients that enhance viscosity and provide body: starch, fiber, and pectin. By making a quick roux and simmering with the hot broth, tomato paste effectively thickens and enriches the flavor of soups. Start with a tablespoon or two per cup of soup and adjust amounts to your preferred thickness. With a few simple tricks, tomato paste can take soup from watery to rich and robust. Experiment with tomato paste as a handy kitchen staple for making all kinds of delicious soups, stews, and chilis perfectly thick and creamy.