Why do you need to blanch potatoes?

Answer 1

The need to blanch potatoes depends on what you are doing with your potatoes. Blanching not only partially cooks the the potatoes, but it also breaks down enzymes within the potatoes that is responsible for their turning black upon standing in the air (oxygen exposure). When roasting or frying potatoes, blanching them first partially cooks them through. When they are then cooked in oil or other fat, the cooking time is reduced, the potatoes are cooked through more evenly, and you minimize the risk of burning the outsides of the potatoes trying to cook them all the way through. Peeled potatoes exposed to oxygen in the air quickly turn brown and eventually black. Blanching potatoes that have had their skins removed breaks down the enzymes responsible for this unsightly color change. This allows potatoes to be stored, whether briefly on the counter top or long term in the freezer.