What is the role of cornstarch slurry in a stir-fry sauce?

Question

Cornstarch slurry explained: how it thickens stir-fry sauces quickly and adds that glossy finish.

Answer 1

Cornstarch slurry in a stir-fry sauce acts as a thickening agent, creating a glossy, smooth sauce that evenly coats all the ingredients, preventing it from being watery.

Detailed Explanation:

The cornstarch slurry is a humble but mighty hero in stir-frying! Here's its full role:

• Thickening: This is its primary job. When cornstarch is mixed with cold liquid (to form a slurry) and then added to a hot liquid (like a stir-fry sauce in the wok), its starch molecules swell and absorb the liquid, causing the sauce to thicken rapidly.
• Coating Power: A thickened sauce beautifully coats all the stir-fried ingredients – the chicken, vegetables, and noodles – ensuring every bite is infused with flavor. A watery sauce would just pool at the bottom of the wok.
• Glossy Finish: Cornstarch gives the sauce a lovely, desirable glossy sheen, making the stir-fry visually appealing.
• Prevents Wateriness: Vegetables release moisture as they cook. The cornstarch slurry helps to bind this released moisture into the sauce, preventing your stir-fry from becoming a watery mess.

To make it: always whisk cornstarch with an equal amount of cold water or broth until smooth. Add this slurry to your stir-fry sauce in the wok at the very end of cooking, stirring constantly until it thickens, usually within 30-60 seconds.

Pro Tip:

If your stir-fry sauce ends up too thick, you can easily thin it down by adding a splash of hot water or broth, stirring until you reach your desired consistency.