Our favorite mashed potato recipe calls for boiling whole potatoes in their jackets, then peeling and mashing them right before serving. Keeping the skins on during cooking yields the best potato flavor, but the method itself isn’t all that convenient.
After boiling the potatoes for 30 minutes, there you are, right before dinner, burning your fingers on hot skins. We decided it was time to revisit this recipe to come up with something that allowed a little more of the prep work to be done in advance.
Ask people their favorite way to make mashed potatoes and most will say the same thing: They peel the skins, chop the spuds, then throw them into a pot of cold water to boil. We like cooking the potatoes in their jackets because it keeps the earthy potato flavor from leeching out into the water, and also because we find it yields the creamiest texture.
The skins prevent the starch granules in the potato cells from absorbing too much water and bursting like overfilled water balloons when mashed, spilling their sticky, gluey contents into the mix. But to meet my goal of cutting back on last-minute prep, clearly the skins would have to go before cooking. Waterlogged starch granules, then, were a given.
Was there a way to prevent at least some of them from bursting? One way is to use a ricer, rather than a potato masher, to finish the dish. Potatoes pass through the sieve-like hopper of this tool only once, avoiding the repeated abuse of mashing. (Pounding already-mashed portions over and over greatly increases the chance of bursting starch granules.)
Ricing aside, what else could I do? I tried a lot of unlikely techniques, most of which yielded poor results. One bright light during this early testing was a recipe in Jeffrey Steingarten’s book, The Man Who Ate.
Everything that employed a technique invented by the instant-mashed-potato industry. Steingarten partially cooks the spuds in simmering water, drains and rinses them under cool water, and sets them aside for half an hour. Once fully cooled, the potatoes are cooked again and mashed. Cooling the potatoes partway through cooking causes the sticky gel in the starch granules to crystallize and become resistant to dissolving in water or milk (even if the cell walls surrounding them subsequently rupture), leading to fluffier potatoes.
The only problem: This meant cooking potatoes for over an hour in numerous changes of hot and cold water. This was not the “advance prep” I had in mind. Another method, recommended on the website of the Idaho Potato Board, was simpler and equally intriguing.
To avoid gluey mashed potatoes, the site suggests a two-step cooking process that has you start the potatoes in actively boiling water (rather than the traditional cold water) and then immediately reduce the temperature to keep the water at a bare simmer.
After 20 minutes, you crank up the heat and boil the spuds until soft. The idea is to keep the pectin that glues individual potato cells together (and helps keep water out) from degrading too quickly. At temperatures below the boiling point, the pectin won’t dissolve and can continue to act as a barrier to water.
Tasted side by side with conventional one-step potatoes started in cold water, the two-step spuds were definitely lighter. But they still tasted more thin and watery than the potatoes cooked with their jackets on. To get both fluffy consistency and great flavor, I was going to have to keep excess water from getting into the starch granules in the first place.
Why not just forget simmering and boiling and go with a method that would expose the potatoes to little or no water? Full Steam Ahead Baking the potatoes was out—it would take too long (plus, if I cooked potatoes with their skins on, I was back where I started).
Microwaving produced a starchy, pasty mash. Steaming was my best bet. I fashioned a steamer by placing a colander in a Dutch oven, then brought a few inches of water to a boil. I peeled, cut, and rinsed the spuds (to remove any surface starch) and dropped them into the colander.
About 20 minutes later, the potatoes were soft and ready for mashing. They were also covered in a sticky substance that I knew to be free amylose, the very thing that turns potatoes gluey.
I tried rinsing the potatoes before ricing to get rid of the amylose, but some of the potato flavor washed away as well, resulting in a mash that was as bland as the two-step potatoes. And the potatoes were now cold. Would rinsing the potatoes earlier in the process, before they got fully cooked, bring me better results? I put a new batch of spuds into the steamer.
Peeking after 10 minutes, I saw they were already covered in gluey amylose. I took the colander out of the pot, rinsed the hot potatoes under cold water for a couple of minutes, then returned them to the pot of still-boiling water to finish cooking. When riced, these potatoes were wonderfully light and fluffy and had the best flavor yet.
Back to Basics
Ideally, this recipe should work with a wide range of potatoes: Russets, Yukon Golds, red potatoes, and white potatoes. But due to their low starch content, the red potatoes were a bust, tasting bland and uninspiring no matter how much butter was added to the mix. While the other potatoes worked fine, tasters liked the deeper flavor of the Yukon Golds best.
With my cooking method solved and the type of potato chosen, I was ready to tackle the butter and mashing liquid. Up to this point, I had been using a stick of butter and a cup of cream. I had been getting complaints all along that the potatoes tasted a little rich—surprising, since these are the very proportions we have loved for so long in our favorite recipe.
Could it be that my cooking method was creating so much rich potato flavor on its own that less butter or cream was now necessary?
As it turned out—yes. Just 4 tablespoons of butter yielded the right amount of richness. As for liquid, my potatoes needed less than the full cup of cream.
Two-thirds of a cup of cream created the right consistency but still left the potatoes too heavy. In head-to-head tests, my tasters actually preferred whole milk to cream or half-and-half.
I now had a fluffy, smooth mash with robust, earthy potato flavor.
And I was able to get it on the table without burning my fingers once on hot skins.
David Pazmiño is one of the 42 test cooks, editors, food scientists, tasters, and cookware specialists who run the Boston-based America’s Test Kitchen (ATK) test kitchen.