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.
No. You don't need to soak potatoes before making them into mashed potatoes.
If you do – just soak them for 5 minutes and rinse. Doing so is a science thing – soaking cut potatoes removes excess potato starch. This means fluffy mashed potatoes (and not gluey!) What can you put in mashed potatoes instead of milk?
Step 1: Soak Potato Pieces
Soak the baking potatoes for just a few minutes in cold water to release some of their starch so the cooked spuds don't get gluey. A combination of starchy bakers and more waxy, buttery Yukon Golds creates an ideal creamy-yet-fluffy final texture in the mash.
How long do you need to soak potatoes? Soaking potatoes for 15 to 30 minutes is sufficient, but you can soak them for up to an hour, if you have other things to do around your kitchen.
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.
You can store peeled potatoes in water in the refrigerator for about 24 hours. Peeled potatoes left out by themselves at room temperature, on a refrigerator shelf or wrapped in foil or plastic wrap will still get dark overnight, so submerge them in a bowl of water, cover and refrigerate.
Potatoes can be peeled prepped and cut into water up to 2 days before boiling for mash.
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.
Once the potatoes have soaked, rinse and drain them. Then — also very important — use a towel to pat them down until they are nice and dry before moving onto the next step.
If you're prepping with smaller pieces, don't soak for more than 12 hours. This trick is handy, but it'll only work for about 24 hours — so don't prep too far in advance. After too long they'll start to take on water and may lose their structure when you go to cook them.
“Salting the water not only seasons the potato, but it also allows it to boil to a hotter temperature. This in turn cooks the potatoes' starch more thoroughly, resulting in a more creamy texture [for mashed potatoes],” says Sieger Bayer, Chef and Partner at The Heritage.
The boiling point
The most important part here is that you use cold water instead of boiled – if you boil the water first, the outside will cook faster than the inside resulting in an uneven texture. Cubed spuds will take around 15 minutes where larger chunks or whole new potatoes will be 20-25 minutes.
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.
Cold Water Soak
A quick rinse under cold water can wash away much of the surface starch. More starch is removed from a cut potato than a whole peeled potato, because a greater surface area is exposed on cut potatoes. Soak them in cold water for as long as a few hours to remove more starch than by rinsing alone.
Leaching method: Peel and dice potatoes. Place in a large pot of warm tap water and soak for 2 to 4 hours. Drain and set aside.
Cover the pot with a lid. Cook the potatoes in gently boiling water until tender, about 15 minutes for small red potatoes, new potatoes or cubed large russet potatoes, and 20 to 25 minutes for quartered potatoes.
Follow this tip: Begin the process of seasoning your mashed potatoes by adding salt to the water when cooking the potatoes. You won't have to add as much salt later and, most importantly, you won't find yourself with bland potatoes.
Bring the water to a boil. Reduce heat to medium low. Cover the pot with a lid and let simmer until fork-tender, about 10-15 minutes for small and/or cubed potatoes or 20-25 minutes for large potatoes. Drain and cool.
But here's the thing: Starchy potatoes soak up water more easily. So you should think of the potato's peel as its protective jacket. If it's removed before boiling, the flesh will soak up too much of the water in the pot.
Rinsing potatoes helps remove excess starch, so it is recommended to rinse the potatoes before cooking. To ensure even more starch is out of the way, it's recommended that they even be quickly rinsed after boiling. We recommend using hot water for rinsing after boiling and cold water prior to boiling.
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).
If your potatoes have been growing in very dry soil, the potatoes themselves will have a fairly low moisture content when harvested. What this then means is that when the potatoes are build they absorb more water and fall to pieces quite quickly.
Always start potatoes in cold water.
water, but potatoes are dense and require more time to heat all the way through. Dropping them into boiling water is a bad idea because the hot water will cook the outsides of the potatoes faster than the insides, leaving you with unevenly cooked taters.