How does saponification change fat into soap?

Saponification is the fundamental chemical process used to manufacture soap by converting natural fats or oils into soap and glycerol.12

Fats and oils are composed of triglycerides, which are esters formed by linking three fatty acid molecules to a single molecule of glycerol. During saponification, these triglycerides are treated with a hot alkali solution, such as sodium hydroxide (caustic soda).312

The alkali acts on the triglycerides, breaking them down through hydrolysis. This reaction releases the glycerol and converts the fatty acids into their corresponding alkali metal salts—the substances we identify as soap. Specifically, using sodium hydroxide results in sodium salts, commonly known as hard soap, while potassium salts result in soft soaps. If industrially produced fatty acids are used instead of natural fats, the reaction yields soap and water rather than soap and glycerol.4321