How to Roast Potatoes That Actually CRUNCH

Most home cooks accept mediocrity when it comes to roast potatoes. You pull the tray from the oven, they look golden, but the texture is all wrong. The skin is leathery. The crunch is fleeting. Ten minutes later, you are eating a soggy starch nugget.

True, audible crunch—the kind that stays crisp even after plating—requires specific chemistry. You cannot achieve it by simply throwing oil on raw tubers and hoping for the best. The secret lies in manipulating the surface of the potato before it ever touches the roasting pan. You need alkaline water.

The Science of Alkalinity

Potatoes are held together by pectin. This structural glue keeps the potato firm. When you boil potatoes in neutral water, the pectin breaks down slowly. If you add vinegar (acid), the pectin strengthens, and the potato holds its shape forever. That is great for potato salad, but terrible for roasting.

We want the opposite. By adding baking soda to the boiling water, you raise the pH. This alkaline environment breaks down the pectin on the potato's exterior rapidly, while the center remains intact. The result is a potato chunk with a firm core and a soft, disintegrating surface. This is not a mistake. It is the objective.

The Cut and The Boil

Start with Russet or Yukon Gold potatoes. Russets give you a fluffier interior; Yukons provide a creamier, denser bite. Peel them. Skin interferes with the texture we are building. Cut them into large chunks—about two inches across. Small pieces will dry out before they crisp.

Place the potatoes in a pot of cold water. Add a generous handful of kosher salt. Then, add the catalyst: half a teaspoon of baking soda. Bring it to a boil.

Boil them until a knife meets little resistance. They should be tender but not falling apart in the pot. If you drain them and they look smooth and firm, you have failed. They need to look a bit ragged.

The Rough Up

Drain the water. Leave the potatoes in the hot pot. Let them steam dry for a minute. Moisture is the enemy of crispiness.

Now, shake the pot. Do not be gentle. You want the cooked exteriors to collide and break apart. The alkaline water has already weakened the surface pectin; the mechanical action of shaking turns that soft surface into a starchy slurry.

When you look at the potatoes now, they should be covered in a layer of mashed potato paste. This paste creates surface area. Surface area creates crunch.

Fat Choice and Flavor Infusion

While the potatoes steam, prepare your fat. Duck fat or beef tallow produces the superior result. These animal fats have high smoke points and add a savory depth that vegetable oil lacks. If you must use oil, choose avocado or light olive oil.

Do not toss minced garlic or herbs onto the roasting pan at the beginning. They will burn long before the potatoes are done, leaving you with acrid, bitter specks. Instead, heat your fat in a small saucepan with rosemary sprigs and smashed garlic cloves. Let them sizzle gently, infusing the fat with flavor. Strain the solids out and keep them for garnish later. You now have flavored fat.

The Roast

Preheat your oven to 450°F (230°C). Convection (fan) is better if you have it.

Pour the infused fat over the roughed-up potatoes. Toss them until that starchy slurry mixes with the fat to form a thick coating. Season with salt and pepper.

Spread them on a baking sheet. Give them space. Crowding the pan causes steaming, which undoes all your hard work.

Roast them for 20 minutes without touching them. The bottom needs to set and brown. Flip them. Roast for another 30 to 40 minutes, turning occasionally, until they are deep brown and sound hollow when tapped.

The result is a potato with a glass-like crust that shatters when you bite it, yielding to a cloud-like interior. Save this method in Foodofile so you never settle for leathery potatoes again.