One of the starch molecules in potatoes is called amylose, which is responsible for making mashed potatoes \”gluey\” and pasty. Rinsing or soaking cut raw potatoes helps to wash away a very small amount of amylose. But the potatoes must be cut into one-inch pieces to expose enough surface area to wash away any significant amount of amylose. It\’s not worth the trouble. Washing parboiled or steamed potato pieces removes much more amylose and is worth the trouble.
The result is very fluffy mashed potatoes. (If you decide to try soaking the raw potatoes anyway, they can be soaked in water in the refrigerator for several hours without any safety concerns. Potatoes can be soaked even overnight as long as they are in the refrigerator. )
Guy Crosby is the science editor for Americaвs Test Kitchen and an adjunct associate professor in the department of nutrition at the Harvard School of Public Health.
I have heard that, to get crispy french fries, I need to get rid of the excess starch on the surface of potatoes after cutting them. But that can\’t be the reason, really, because starch is actually what FORMS the crust. so my reasoning is the following: we soak them because enzymes released by cutting will quickly convert the starch into glucose, and THAT will caramelise and burn our french fries.
Is that the reason why we use cold water, to keep the enzyme inactive? If so, soaking in cold water seems unnecessary to me. Thoroughly rinsing until the water runs clean should be enough. Am I correct?