For Extra Crispy Roast Potatoes, Boil Them With Baking Soda First
People love potatoes on either side of the pond, but surprising trans-Atlantic discrepancies can be perceived if you press prospective spud-eaters about their preferred form of potato preparation. According to Zippia, many Americans don't believe their Thanksgiving Day feast would be incomplete without a side of mashed potatoes on the table. However, over in the U.K., roast potatoes outrank even roast turkey in the list of best festive feasting foods.
When done right, a great roastie combines the creamy, fluffy, gravy-soaking powers of mash, with the crispy, crunchy, shattering crust of a French fry. Getting to that platonic potato ideal of contrasting textures is the tricky part, though. The starting point is potato selection — roasted potatoes are best made with starchy, rather than waxy, spuds. These varieties, such as russet or Maris Piper, have a texture that can be off-putting in a boiled potato, and doesn't make great mash but are perfect for roasting. Not only will the centers be a creamy dream, but the outsides of starchy potatoes also break down better than waxy ones, which is crucial to get that crackly, caramelized crust.
The process for perfect roast potatoes begins with parboiling them — and according to The Daily Express, this is where you can supercharge your potatoes' crispiness by adding baking soda. Chef Lisa Marley said that it "helps the outside of the potato break down, leading to a starchy paste when gently shaken, creating an extremely crispy outside when roasted."
Spud Science
Most people are good with the idea of acid in food. It really only takes a splash of lemon juice to get into a small cut on your hand before you understand that some foods, especially the sour or tangy varieties, are acidic. But there is more mystery surrounding culinary uses for the other end of the pH scale, the alkaline — even though most kitchen cupboards contain baking soda, a food-safe alkali. Flavorwise, they are described as bitter, maybe even soapy. However, just as dishes like ceviche use chemistry to cook raw fish with acid, we can use alkaline solutions to impact the chemical properties of our potatoes and get better results.
Potatoes cooked in acidic water hold their shape better, meaning you can make fries that are super soft but are still recognizable sticks of potato, not an unfryable mush. But fries only spend a few minutes in the fryer, to get crispy, whereas roasties have up to an hour in the oven to finish cooking to the middle. Potatoes cooked with an alkali such as baking soda will start to go crumbly at the edges much quicker, which makes it easier to get those shatteringly creviced outsides when you parboil them.
One final tip per The Guardian — to improve the flavor of your roast potatoes, add some of your (clean) potato peels to the pot as well as the baking soda.