You could be using the wrong potatoes. Potatoes are generally considered "waxy" or "starchy." Waxy potatoes (like white potatoes and red potatoes) are more prone to gumminess when mashed, as opposed to starchy potatoes (like Yukon Golds and russets). Choose starchy potatoes or a mixture of waxy and starchy potatoes.
We consider Yukon Gold potatoes the best choice for classic dense mashed potatoes. Their rich texture and subtle creaminess make them great for all of your mashing needs. A true all-purpose potato, they're also good for shredding, roasting, grilling, blending (?!), and shingling.
Yukon Gold potatoes (yellow) are the best varietal for pomme purée—and they're easy to find. Dice the potatoes for even cooking. Start the seasoned, diced Yukon Golds in cold water, bring to a rapid boil, then turn down to simmer for a gentle cook.
The Mistake: Overworking the Potatoes with a Food Processor, Blender or Mixer. Too much — or too vigorous — mashing will produce gluey potatoes. Your best tool is an old-fashioned masher, fork, ricer or food mill.
Medium-starch potatoes are the round white potatoes and yellow potatoes. They are a great all-purpose potato and are the types you'll most commonly find in the grocery store. They are versatile and can be used in almost any dish, whether roasting, grilling, mashing or boiling.
Using the wrong type of potatoes
Choose higher starch potatoes like Russets or Yukon Golds for the fluffiest, smoothest and most flavor-packed mash. Russet varieties mash up light and fluffy, while yellow-fleshed potatoes like Yukon Gold have a naturally buttery flavor and creamy, dense consistency.
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.
Once there is too much starch in your mashed potato mixture, the texture will quickly turn from fluffy to gummy. Instead of using an electric hand mixer, food processor, or blender — all of which will overwork the potatoes — use a ricer, food mill, or hand masher to gently break down the spuds, per The Spruce Eats.
Start With the Proper Potato
You want to avoid low-starch, high-moisture potatoes such as red bliss or white potatoes, which need more exuberant mashing to break them down, potentially overworking the starch and turning them gluey.
AMERICA'S FAVORITE MASHED POTATOES
If you've been debating trying Idahoan mashed potatoes, take comfort in the fact that they are real potatoes, with quality ingredients. Many of your friends, family and neighbors have tried us and love us. After all, they are America's favorite mashed potatoes.
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.
Red potatoes are considered waxy, meaning they have more moisture / less starch. They are great for mashing because they are naturally smooth and creamy. That said, take care to not over-mash as they can become gluey faster than russet or Yukon gold potatoes.
Red Potatoes
are advantageous for boiling, pan frying, grilling, scalloping, and steaming. Try them in your salads, soups, chowders, and fried potato dishes. …have a smooth, thin light-red skin with a white inside. In fact, if you're not careful when cleaning them, you can easily scrub the skin right off!
The Maris Piper has a golden skin and creamy white flesh with a fluffy texture. This makes it a versatile all rounder, great for chips and roast potatoes, but also good for mash and wedges.
You shouldn't let butter be the only dairy you use, however. Consider adding half-and-half or heavy cream and a bit of sour cream (even goat cheese) to get the best flavor and creamiest texture every time, like in these Best Mashed Potatoes.
For fluffy mashed potatoes, we recommend using high-starch, low-moisture potatoes like russets. Mashed taters are made by crushing cooked potatoes into fine particles, and then coating those particles in fat and water (usually in the form of butter and milk or cream).
Fix them: Scoop the watery mashed potatoes into a pan and stir constantly over low heat to evaporate the excess liquid. If the potatoes are really watery, you can add either cornstarch or instant mashed potatoes a half teaspoon at a time to help the spuds thicken to your preferred consistency.
The trick to the most fluffy mashed potatoes is to add a leavening agent like baking powder or baking soda. Just a pinch of baking powder added to the drained, cooked potatoes can help make them so fluffy.
“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.
Step 1: Soak Potato Pieces
1. 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.
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.
When you melt butter on the stove, its milk solids and fat separate. Adding cold butter to your potatoes will allow the butter to melt as a whole and distribute the fat and milk solids evenly.
A word about butter: Don't melt butter before stirring it into the potatoes because the milk solids and fat will separate. You can add cold butter to your hot potatoes since the butter will melt as a whole and distribute the fat and milk solids evenly.