Cornstarch must be dissolved in cold water, added to a mixture, then boiled for several minutes for it to thicken.

Question

Quizplus · Accepted Answer

This is the correct method for thickening with cornstarch. If cornstarch is added directly to a hot mixture, it can clump up and not thicken uniformly. Dissolving it in cold water helps prevent this. Boiling the mixture activates the thickening properties of the cornstarch.

Cornstarch Must Be Dissolved in Cold Water, Added to a Mixture