What does reduction refer to in cookery?

Reduction in cookery specifically refers to the process of simmering or gently boiling a liquid, such as a sauce or stock, over heat until it evaporates and thickens. This technique concentrates the flavors, intensifying the taste and creating a richer consistency in the sauce or liquid. It allows for the development of complex flavors as the liquid's water content diminishes, resulting in a more robust final product that can enhance a dish.

In contrast, the other options describe different cooking techniques that do not involve the concentration of flavors through evaporation. Frying food quickly does not relate to reduction, as it primarily focuses on cooking with fat and achieving texture rather than manipulating liquid consistency. Boiling food in water is a method for cooking but does not contribute to thickening a sauce or liquid. Freezing food for preservation involves stopping the cooking process altogether and does not pertain to altering the liquid’s concentration. Thus, the correct choice highlights a key culinary technique essential for flavor enhancement in various dishes.