Why do some soups jellify?

Soups can jellify for a few reasons, mostly related to the ingredients and cooking process:

1. Gelatinous Ingredients:

* Bone broth: The collagen in bones breaks down into gelatin when simmered for a long time. This gelatin is responsible for the thickening and jelling of broths and soups.

* Cartilage: Similar to bone broth, cartilage also contains collagen which transforms into gelatin during cooking.

* Gelatin: Some soups use gelatin directly for added texture, such as in consommé.

2. Starches:

* High-starch vegetables: Vegetables like potatoes, carrots, and peas contain starch that can thicken a soup. If the soup is allowed to cool, the starch will set up and make it gel-like.

* Flour or cornstarch: These are often used as thickeners in soups. While they typically don't create a true jelly, they can make a soup thicken considerably upon cooling.

3. Cooling Temperature:

* Lower temperatures: The gelatin and starch in a soup will solidify as it cools, resulting in a jelling effect. This is especially noticeable when a soup is refrigerated.

4. Acids:

* Acidic ingredients: Adding acidic ingredients like tomatoes, vinegar, or citrus juice can sometimes break down the proteins in a soup and cause it to gel.

5. Overcooking:

* Excessive simmering: Over-simmering a soup with bone broth or cartilage can make it too gelatinous, leading to a very firm texture.

Preventing Jelling:

* Strain the soup: Strain out solid ingredients like bones and cartilage before serving to reduce the amount of gelatin in the soup.

* Use less gelatinous ingredients: Reduce the amount of bone broth or cartilage in the recipe.

* Add less starch: Use a lighter hand with starch thickeners.

* Avoid overcooking: Follow the recipe's cooking time guidelines to prevent over-simmering.

* Serve hot: Serve the soup while it's still hot to avoid jelling.

Note: Jelling in soups is often a desirable trait, especially in consommés and rich broths. However, if you prefer a thinner consistency, you can use the above tips to prevent jelling.