No, cornstarch is not soluble in water in the traditional sense. When cornstarch is mixed with water, it does not dissolve like salt or sugar. Instead, it forms a suspension where the starch particles remain intact and suspended in the water.
When you stir cornstarch into water, the outer layer of the starch granules can absorb some water, causing them to swell. This process is known as gelatinization, and it usually happens when the mixture is heated. At high temperatures, the granules explode, releasing starch molecules that thicken the water, creating a gel-like consistency. This property is what makes cornstarch an excellent thickening agent in cooking.
So, while cornstarch doesn’t dissolve in water, it interacts with it in a way that can change the texture and viscosity of the mixture, especially when heat is applied.