Pasta swells as it cooks because starch granules absorb water and soften.

The longer version

Dried pasta is mostly starch packed into a dense, glassy structure with very little water in it. Once it enters boiling water, heat and moisture penetrate from the outside inward, and the starch granules take up water and swell. Around the same time, proteins in the wheat soften and form a network that keeps the shape from collapsing.

The result is a larger, softer piece with a hydrated outer layer and a slightly firmer center. Starch that leaches into the cooking water is what makes that water cloudy and helps a sauce cling. Different shapes and thicknesses simply change how long the migration takes.

Where this entry sits

Everyday ingredients turn out to be full of quiet chemistry and long history. This collection gathers short, plain explanations of how bread rises, why onions sting, where common spices originate, and how coffee, tea, and chocolate reached the modern kitchen. The full list sits on the Food and Drink page, where every entry is listed in order.