Starch and Sugar Chemistry

Starch granules are microscopic packets of amylose (long, straight chains) and amylopectin (branched chains). In cold water, they're insoluble—flour stirred into cold water makes a cloudy suspension, not a solution. When heated to 140-180°F (60-82°C) in water, granules absorb water, swell to many times their original size, and burst, releasing amylose into the liquid. This process—gelatinization—is what thickens sauces, gravies, and puddings. Different starches gelatinize at different temperatures and produce different textures: cornstarch creates a clear, glossy gel; flour creates an opaque, matte gel; tapioca creates a translucent, stretchy texture.