Only Using Russet Potatoes
To be clear, there are two types of potatoes. Not French fries and potato skins (although we’re willing to hear this argument), but starchy and waxy. There’s actually a starchy to waxy spectrum: ruddy-skinned russets and Idahos being on the very starchy end, and thin-skinned new potatoes on the other. Russets cook up very light and fluffy, while waxier spuds hold their shape better, which makes them ideal for roasting and potato salad. Our preference: A mix of russet potatoes and a nice, middle-of-the-road potato like Yukon Gold. Mashed together, these potatoes are sturdy enough to handle a decent amount of dairy, but with enough airy volume to keep things from feeling too heavy.
Forgetting to Wash Them Before Simmering
Oof. It may sound obvious, but many of us typically forget this step—you’re submerging them in water, after all. But potatoes grow underground, and they’re covered in dirt. When you simmer a dirty potato, the soil and other bits of grime will pull away from the skin and “flavor” the water, which then gets absorbed by that very potato. The result? A dirt-flavored spud.
Dropping the Potatoes in Boiling Water
When cooking starchy foods like potatoes, be careful not to overcook the outside before the inside is sufficiently tender. By dropping raw potatoes right into a pot of boiling water, their exterior will likely be completely mushy by the time the interior is considered edible. Instead, try to get everything in the pot to come to the same temperature at the same time. Add potato pieces to the pot, cover them with water until they’re just submerged, then turn on the stove. And rather than aggressively boiling them, keep them at a steady simmer for more even cooking.
Under-Seasoning the Potatoes
Potatoes are, by nature, really starchy, and starches require a decent amount of salt to taste good. Adding tons of salt to the water your potatoes boil in is necessary to get the seasoning inside the spuds. Under-seasoning means only the outside of your potatoes will taste like anything, which accounts for very little of the finished dish. Cooking your potatoes in very generously salted water—about a tablespoon of water per pound of potatoes—means the potatoes will be seasoned all the way through. Once mashed, they’ll need a lot less salt on the back end.
Using the Wrong Mashing Tool
A food mill or potato ricer is the way to go here. Pummeling your cooked spuds in a food processor is a surefire way to end up with a way-too-gluey texture; forks and handheld potato mashers are inconsistent, leaving you with some overly mashed bits and other untouched clumps. A mill or ricer is the best balance of mechanical and physical. Their holes will extrude the potatoes evenly, consistently, and with little effort. If you mash potatoes with a stand mixer, use the paddle attachment.
Not Using Enough Butter
If there’s a time and a place to submit to the extra stick, Thanksgiving or Christmas Day is it. Some fancy French mashies call for more than a stick of butter for every pound of potatoes. You don’t have to go crazy, but don’t skimp.
Using Butter Alone
That said, potatoes need more than just butter to be truly delicious. Whether you cook them in half-and-half or milk or add heavy and/or sour cream at the end, a little extra dairy creates a luscious texture and infuses other flavors into the dish.
Not Using Fresh Herbs
If you’re mashing your potatoes with a little (or a lot) of dairy, take advantage. Potatoes will mash easiest with warm liquid. To give that certain je ne sais quoi to your taters, add a few sprigs of fresh rosemary, thyme, or sage to the milk before heating. Even a single bay leaf can add big flavor to humble spuds. While you’re at it, add a teaspoon of black peppercorns (just don’t forget to fish them out), a strip of lemon zest, or a few shavings of nutmeg.
Not Saving Your Potato Water
To mash ahead or not to mash ahead, that is the question. The short answer: Yes you can mash your potatoes ahead of time but only if you save some of your starchy potato cooking liquid. Even if your potatoes are set up a bit, a glug of warm liquid will loosen them up just fine. Be sure you add slowly—you can always add more, but you can’t take it out.
Not Making Donuts With The Leftovers
Or quesadillas, egg rolls, or waffles. Big mistake. Huge! When there are 20 mind-blowing ways to use up leftover mashed potatoes. Not that you’ll have any.
