How does jelly set?

Jelly sets through a process called gelation. This occurs when gelatin, a protein found in animal skin, bones, and connective tissue, is mixed with water and heated. The gelatin molecules unfold and disperse in the water, creating a solution. As the solution cools, the gelatin molecules begin to reassociate and form a network of cross-links, creating a semi-solid structure that traps water molecules within its mesh. This network of cross-links gives jelly its characteristic wobbly, elastic texture.

The exact mechanism of gelation involves the formation of hydrogen bonds between the amino acid residues of the gelatin molecules. These hydrogen bonds create a strong, cohesive structure that holds the water molecules in place, preventing them from flowing freely. The strength of the gel depends on the concentration of gelatin in the solution, as well as the temperature and acidity of the mixture.

Other factors that can affect the setting of jelly include the presence of other ingredients, such as sugar, acid, or enzymes, which can interfere with the formation of hydrogen bonds and alter the texture of the gel.