Doing so is a science thing – soaking cut potatoes removes excess potato starch. This means fluffy mashed potatoes (and not gluey!)
No. You don't need to soak potatoes before making them into mashed potatoes.
How long can peeled and cut potatoes sit in water before cooking, before they begin taking on too much water? A: We usually recommend no more than 24 hours. You can keep the potatoes from absorbing the water by making sure the water is not salted, and is chilled (you can even add ice to the water).
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.
Give them a cold water bath: Once your potatoes are chopped, toss them into a large bowl. Then cover the potatoes completely with cold water and let them soak for at least 30 minutes (or up to overnight). This will help to rinse off the excess starch and help the potatoes crisp up beautifully in the oven.
Soaking potatoes in water helps remove excess starch. Excess starch can inhibit the potatoes from cooking evenly as well as creating a gummy or sticky texture on the outside of your potatoes.
The Mistake: Cutting Potatoes Into Too-Small Pieces
They'll absorb too much water during cooking, preventing them from soaking up all the yummy butter and cream when it comes time for mashing. The best-size chunks for boiling: about 1 1/2 inches.
For most potato dishes it's important to add the potatoes to cold water and allow the water to come to a boil with the potatoes in the water. The potato starch can react as soon as it comes in contact with hot water, which will promote uneven cooking and mealy potatoes.
Swap Out the Water
In fact, when you mix the potato flakes with the warm broth, the result is a creamier, more buttery-tasting bowl of spuds. You can also swap milk or half-and-half for the water required.
Here's what not to do: Don't boil your potatoes ahead and wait to mash them, even for half an hour, and don't hold mashed potatoes in a slow cooker. Both result in a mash so gluey that even a paste-eating kindergartener wouldn't touch them.
Put the cut potatoes in a large pot.
Add salt to the water, if desired. Bring the water to a boil over high heat, then reduce heat to medium low.
Just be sure to store peeled potatoes in water for no more than 24 hours. After that, the cool refrigerator air will convert the starches in the potatoes to sugar, causing the flavor and texture of the spuds to change. Instead, just start cooking potatoes for a mash, potato salad, or hash browns.
Soak raw potatoes in a container for up to four hours. The potatoes should be fully submerged to prevent oxidation and discoloration. After four hours, the potatoes should be rinsed with cold water. Chopping, cutting or otherwise slicing the potatoes will excrete more starch.
If kept warm, gently mash in heavy cream until smooth and loose again, adding more if you'd like. If cold, heat the cream in a large pot until steaming, then add the potatoes. Gently mash and whip, adding more cream as needed, until heated through and fluffy.
CREAMED MASHED POTATOES Add 85g/3oz butter and 150ml/5-6fl oz double cream to the mashed potato. Season to taste with salt and freshly ground black pepper. Add nutmeg to taste and mix until smooth and creamy.
The yolk emulsifies water and fat to create a cohesive, velvety bite, while providing a little fat and body of its own. What is this? You can add an egg yolk to nearly any existing mashed potato recipe.
Don't soak cut potatoes longer than overnight.
If keeping potatoes in water for more than an hour, refrigerate. However, don't soak them any longer than overnight—after that, the potatoes start to lose their structure and flavor.
Skip the whole milk and go for half-and-half or cream.
Liquid dairy is what makes mashed potatoes luscious and creamy. Since it's Thanksgiving, splurge a little and use half-and-half or splurge a lot and use cream.
They absorb liquids brilliantly, which is why they mash so well. But when you boil them in water, the liquid they are absorbing is just that, water, which can make for a less flavorful mash. By boiling the potatoes in salted milk, they are absorbing creaminess and seasoning, which makes them inherently more flavorful.
Start cooking the potatoes in cold water: This ensures that the potatoes cook evenly. Otherwise, if you start with hot or boiling water, the outsides of the potatoes cook and soften while the middles are still hard and crunchy.
Water will move from an area of less salt to more salt (more water to less water), and so when the potato is placed in the saltwater, all the water that is inside the potato (yes, plants have a lot of water inside of them, that's what gives a plant it's structure) moves out by osmosis.
Here's how to do it: For every pound of potatoes in your mash, drizzle 1 tablespoon of melted butter over the dish and fold it gently into the potatoes. If the mash is still too gluey for your liking, repeat the process with another tablespoon of butter.