Acid curd cheese is frequently classed as a soft cheese, but is fundamentally different. The curds are formed solely by the action of lactic acid upon the casein. Acid curdling is a completely different action from rennet coagulation and yields a curd of high acidity, quick drainage properties and somewhat granular texture. The cheese has a clean, acid flavour, and a slightly granular, soft, spreadable texture. It has a short shelf life and must be eaten in a fresh state.