c. boiling water

Boiling water is water heated to its boiling point (100°C or 212°F at sea level), at which the liquid phase transitions to steam. This fundamental culinary medium is characterized by vigorous bubbling and rapid evaporation, producing steam at atmospheric pressure. The term "c." typically denotes a standard volume measurement in culinary contexts (approximately 240 milliliters in the US customary system). Boiling water is chemically identical to regular water (H₂O) but is distinguished by its elevated temperature, which dramatically alters its functional properties in cooking.

Boiling water is essential across virtually all culinary traditions as a cooking medium for pasta, rice, legumes, vegetables, and grains, as well as for blanching and parboiling techniques. It serves as the base for stocks, broths, soups, and infusions (tea, coffee), and is used to dissolve dry ingredients, bloom gelatin, or temper ingredients. The high temperature facilitates rapid heat transfer, accelerates chemical reactions (including gluten development in pasta), and aids in protein denaturation. In pastry work, boiling water creates steam for baking, while in beverage preparation it extracts flavors from dried botanicals and coffee grounds.