The 1-Ingredient Upgrade for the Fluffiest Mashed Potatoes (It Costs Zero Dollars)

My ideal mashed potatoes are perfectly seasoned, light, super fluffy, and free of lumps. I take making them pretty seriously because they're one of my favorite foods ever. A ricer must be used, butter should be added with abandon, and if the dairy is anything lighter than heavy cream, I don’t want the mashed potatoes.

I used to attribute the success of making mashed potatoes to the type of potato used, how long they were cooked, and how they were mashed. While all of these things are important, a few years ago I learned a ground-breaking trick from cookbook author J. Kenji López-Alt that trumps all other factors. What if I told you the key to the fluffiest mashed potatoes is one ingredient that also happened to be free? 

It’s nothing fancy like cultured butter or crème fraîche—although neither could hurt the cause! The secret ingredient is just ice-cold water.

If you’ve ever made French fries from scratch, you may be familiar with soaking the cut potatoes in cold water to pull out excess starch. This gives you French fries that are crisp and golden, while the insides are light and fluffy. 

The same trick applies to mashed potatoes—it's so obvious I wish I would have thought of it myself! You soak the potatoes in iced water before they are cooked. This eliminates much of the starches in the potatoes, resulting in a super light and fluffy mash.

It's also like when you make rice. The key to fluffy rice is to rinse off as much starch as possible. That way the grains don't bloat and aren't drawn together by the excess starch into clumpy, mushy lumps. Also, just like when you rinse rice, you can see the starch leaching out of the potatoes as they soak—you'll see the water turn white.

Here's what I do to rinse the starch off the potatoes:

Fill a large bowl with cold water and a handful of ice. Add the peeled potatoes to the water and let them sit for at least 30 minutes, though one hour is ideal. Then carefully remove the potatoes with your hands or a spider strainer so that the starches pooled in the bottom of the bowl aren't disturbed.

Boil the potatoes until they are tender, proceed with your favorite mashed potato recipe, and you'll notice that they are way fluffier than when you made them without soaking.

I take this one step further: After draining the cooked potatoes into a colander, I rinse them under cold running water to knock off the starches on the surface. Since this will cool the potatoes and add some moisture, I return them to the pot and steam them for a minute or two over low heat. This brings the temperature back up and cooks off any added water.

Mashed Potatoes Rules I Live By

• Start the potatoes in cold water. Lumpy mashed potatoes are usually a direct result of potatoes that were not cooked evenly. When you start potatoes in warm water, the outsides cook faster than the insides, leading to dreaded lumps. Start them in cold water. The potatoes should be covered with water by at least an inch.
• Use a ricer! Be very wary of any potato recipe that has you use a blender or food processor. The fastest way to make potatoes gummy is to process them with lots of power. I’m not big on single-use kitchen tools, but a ricer is the only tool that will give you fluffy, smooth mashed potatoes.
• Don’t shy away from salt. Like pasta, it’s hard to season potatoes after they have been cooked. You want the cooking water to taste like the sea; this will ensure your spuds have some serious flavor. Adding salt after they are cooked will just make the mashed potatoes taste salty, not well-seasoned.