The Science-Backed Secret to the Crispiest Roasted Potatoes

As fall approaches and we begin to think of comfort foods to keep us warm throughout the winter, one food is top of mind: potatoes. Mashed, baked, boiled, or roasted, there’s just something about butter-smothered or perfectly-seasoned potatoes warming our bellies that makes us feel cozy inside.

 When it comes to roasting potatoes, did you know there’s a secret to making them the crispiest ever? And you probably have the ingredient you need in your pantry already.

 The secret ingredient? Baking soda.

Why Does Baking Soda Make Potatoes Crispier?

In his recipe for crispy roasted potatoes, Chef John adds baking soda to the water before boiling to raise the spuds' pH balance, a trick he learned from J. Kenji López-Alt and the team at Serious Eats. 

 According to the experts, raising the pH balance in the water helps break down the pectin, or the natural cellular “glue” that holds vegetables together, quickly, while roughing them up at the same time. López-Alt says that breakdown of the pectin creates more of a starchy slurry and a larger, rougher surface area. "It’s this roughed up, shaggy, starchy surface that results in such a profound level of crustification during the roasting process," explains Chef John. 

In Chef John's recipe you bring 6 cups of water to a boil with 4 1/2 teaspoons of kosher salt and a scant 1/2 teaspoon of the baking soda.

After Chef John boils the potatoes, he tosses them in a mixture of oil and spices—the same that he used while working in a diner during high school—checking to be sure the potatoes are evenly coated before popping them into a 450-degree-F oven. And voilà! In 45 to 60 minutes you have extra-crispy oven roasted potatoes!

More Tips for the Crispiest Roasted Potatoes

If you don't happen to have baking soda on hand Chef Nick Ocando, director of culinary overseeing Allelo, Juno & the Peacock and Pluma Lounge in downtown St. Petersburg, Florida, has a few tips on how he makes his crispy roast potatoes without it:

•  “Always make sure your potatoes are as dry as possible—‘free of all water’—by drying them with a paper towel before seasoning,” says Ocando. “Excess moisture makes them steam instead of roast.”
• He also says to not overcrowd your roasting pan, roast in single layers, and season right before you cook them, “because salt will pull moisture to the surface and cause your potatoes to steam instead of roast.”

There you have it, the secret to making your crispiest pan of roasted potatoes yet. Combine this method with our secret for the best roasted potatoes you'll ever taste and you might get the best potatoes you've ever had.