cornstarch plus 2 tablespoons water

Cornstarch is a fine white powder derived from the endosperm of corn (maize) kernels through a process of milling and separation. It is primarily composed of amylose and amylopectin, two forms of starch that account for approximately 99% of its dry weight. When cornstarch is combined with water—as in the ratio specified (cornstarch plus 2 tablespoons water)—it forms a slurry or suspension that is commonly used as a thickening agent in cooking. This mixture exploits the gelatinization property of starch: when heated, the starch granules absorb water, swell, and release amylose, thereby increasing the viscosity of liquids and creating a glossy, smooth texture in sauces, gravies, and other preparations.

Cornstarch is flavorless, odorless, and neutral in taste, making it an ideal thickening agent that does not impart flavor to dishes. It is widely produced in the Americas, Europe, and Asia, with the United States being a major producer.

Cornstarch-water slurries are employed across numerous cuisines as a primary thickening agent for sauces, gravies, soups, and braising liquids. In Asian cooking, particularly Chinese cuisine, this preparation is essential for creating the glossy, viscous consistency characteristic of stir-fry sauces and pan sauces. The mixture is typically added to hot liquids near the end of cooking, where the heat causes rapid gelatinization. A standard ratio of 1 part cornstarch to 2 parts cold water produces a medium-bodied slurry suitable for most applications. This technique yields a clear, smooth result when properly incorporated, though overstirring after thickening can cause the starch to break down (retrogradation) and thin the sauce.