The answer to how a too-thin soup can be thickened: adding a starch-based thickener to the soup, boiling the soup uncovered to evaporate its excess water, or taking some of the soup, puréeing it, and mixing it back into the whole. Applying one or more of these three methods brings the soup to the desired consistency without sacrificing flavor.
A soup being too thin is usually caused by using more water than stated in the recipe or not cooking it long enough. When a soup has too much liquid, its flavor also becomes diluted; that's why thickening is a step that strengthens not just the texture but the taste as well. A starch or flour-based mixture, once combined with water and cooked with heat, gives the soup body.
What's the Method for Thickening a Thin Soup?
One of the following methods can be applied to increase the soup's thickness.
- A small amount of cornstarch should be mixed smooth with cold water, then slowly added to the boiling soup.
- The soup can be boiled uncovered over medium heat for a few more minutes to allow the excess water to evaporate.
- A ladleful can be taken from the soup, its vegetables or legumes puréed, and mixed back into the soup.
- A small amount of flour, mixed with cold water until lump-free, should be added to the soup.
- After thickening, the soup should be boiled for a few more minutes so the taste of the starch or flour disappears.
What Are Common Mistakes When Thickening Soup?
Some mistakes that lead to an unwanted consistency in soup are repeated frequently.
- Adding starch or flour directly to hot soup without mixing it smooth first causes clumping.
- Thickening the soup too quickly and in too large an amount can bring it to too thick a consistency.
- Not checking for sticking at the bottom while boiling the soup uncovered increases the risk of burning.
- Serving the soup right after adding the thickener can result in the raw ingredient's taste being noticeable.
Which Thickening Method Suits Which Soups?
For vegetable soups, taking some of the soup and puréeing it gives both a natural and practical result; since this method requires no extra ingredients, it preserves the soup's own flavor. For meat- or chicken-based soups, starch-based thickeners give a faster and more consistent result. For legume soups like lentil or chickpea, long boiling is often enough on its own to achieve sufficient thickness.
The timing of when the soup is thickened also matters; if thickening is done not right before serving but a few minutes before, both the consistency settles and the taste balances out. If the soup will sit for a while, it's better to leave it slightly thin and do a final thickening just before serving, which prevents the soup thickening too much as it rests and becomes overly thick.
The amount of thickener used also directly affects the result; adding it in small amounts and checking the consistency as you go prevents the soup from suddenly reaching too thick a consistency. A thickened soup's consistency can increase a bit more after it rests for a while; that's why leaving it slightly thin on the first addition is a safer approach than adding extra thickener afterward.
Thickening a too-thin soup is possible with starch- or flour-based thickeners, uncovered boiling, or vegetable-purée methods. When these methods are applied correctly, the answer to how a too-thin soup can be thickened becomes practical, and the soup reaches the desired consistency. Starting with small amounts and checking the consistency as you go is the most reliable approach.