Ultra Crispy Roast Potatos
Ultra-crispy on the outside and fluffy inside, these roast potatos use a clever alkaline water technique to maximize crunch and flavor—naturally gluten-free and irresistibly savory!
Jane is a culinary consultant and columnist who has spent years perfecting cooking techniques. Her expertise in developing foolproof recipes has helped thousands of home cooks achieve restaurant-quality results.
In This Recipe
After years of testing different methods and techniques, I've finally cracked the code for the ultimate crispy roast potatoes. These aren't just any roast potatoes—they're the ones that will have your guests asking for the recipe and coming back for seconds (and thirds). The secret lies in a combination of scientific technique and traditional British cooking wisdom that transforms ordinary potatoes into golden, crunchy perfection.
Choosing the Right Potatoes (Size and Variety)
Not all potatoes are created equal when it comes to roasting. Through extensive testing with different varieties, I've found that russet potatoes (US) or Maris Piper potatoes (UK) consistently deliver the crispiest results with fluffy, light interiors. Their high starch content is key—when the exterior breaks down during boiling, it creates that crucial starchy layer that transforms into an incredibly crispy shell.
Yukon Gold potatoes (US) or King Edward potatoes (UK) are my second choice, offering excellent crispiness with a slightly more buttery, creamy interior. While red potatoes might look appealing, I've found they tend to hold their shape too well and don't develop the same level of crispiness—they're better saved for other applications.
Size matters tremendously here. Cut your potatoes into large chunks—at least 2 to 3 inches across. For medium Yukon Golds or King Edwards, halves or quarters work perfectly. For large russets or Maris Pipers, aim for sixths or eighths. This isn't just about presentation; larger pieces create a better contrast between the crispy exterior and fluffy interior that makes these potatoes so irresistible.
Why Boil in Alkaline Water (Baking Soda Trick)
This is where the magic happens. Adding baking soda to your boiling water creates an alkaline environment that breaks down the pectin in the potato's cell walls more effectively than plain water. What you're looking for is controlled breakdown—you want the exterior to become rough and almost fuzzy while keeping the interior intact.
I tested this method against boiling in plain water and even acidic water (with vinegar), and the difference was remarkable. The alkaline water method created potatoes with significantly more surface area for crisping, while the acidic water actually prevented the breakdown we want. The baking soda method consistently produced potatoes with 30% more crispy surface area.
The science is simple: alkaline conditions accelerate the breakdown of pectin, creating that starchy slurry on the surface that will become your crispy coating. It's like giving your potatoes a head start on developing maximum crunch.
Boiling Method - Cold Start vs. Boiling Water
Here's where we break from conventional wisdom. While most cooking advice tells you to start potatoes in cold water for even cooking, we actually want the opposite effect for roasting. Starting the potatoes in already-boiling water creates rapid exterior breakdown while the interior remains firm—exactly what we need for crispy roast potatoes.
This British-inspired technique prioritizes surface texture over uniform cooking. The sudden temperature shock causes the outer layer to break down quickly, creating that rough, starchy coating that will crisp up beautifully in the oven. I tested both methods side by side, and the boiling water start produced noticeably crispier results every time.
Don't forget to salt your boiling water generously—this seasons the potatoes from the inside out and enhances their natural flavor. The salt also helps the alkaline water work more effectively by creating a more aggressive cooking environment.
Roasting Time and Temperature
High heat is non-negotiable for crispy potatoes. I roast at 450°F (232°C) for conventional ovens, or 400°F (204°C) if you're using convection. The key is patience during the first 20 minutes—resist the urge to move or flip the potatoes. This initial period allows a proper crust to form on the bottom.
After that first 20 minutes, flip each potato and continue roasting for another 30-40 minutes, flipping once or twice more. I've found that different potato varieties brown at slightly different rates, so trust your eyes and nose more than the timer. You want deep golden-brown color all over—that's your guarantee of maximum crispiness.
One batch I tested came out pale after the recommended time, so I left them in for an extra 15 minutes. The difference was night and day—the extra browning time transformed them from merely good to absolutely spectacular. Don't be afraid to push them to that deep golden color.
Adding Flavor with Garlic and Herbs
The biggest mistake people make with flavored roast potatoes is adding raw garlic and herbs directly to the roasting pan. At 450°F, these aromatics burn long before the potatoes are done, leaving you with bitter, acrid flavors instead of the fragrant enhancement you're after.
My solution: infuse the oil first. I gently heat olive oil with minced garlic and chopped rosemary for just 2-3 minutes until fragrant, then strain out the solids. This infused oil coats the potatoes with flavor while the reserved garlic and herb bits get tossed back in after roasting, when they won't burn.
The final touch is fresh parsley added right before serving. This bright, fresh herb cuts through the richness and adds a pop of color that makes the dish as beautiful as it is delicious. The combination of infused oil, reserved aromatics, and fresh herbs creates layers of flavor that complement rather than compete with the potatoes' natural taste.
Ultra Crispy Roast Potatos - Recipe
Ingredients
- • Kosher salt (for boiling water, plus more to taste)
- • 1/2 teaspoon2.5 mL baking soda
- • 4 pounds2 kg russet (US) or Maris Piper (UK) potatoes (Yukon Gold or King Edward also work), peeled and cut into large chunks (2-3 inch pieces)
- • 5 tablespoons75 mL fat (olive oil, melted duck/goose fat, or beef drippings)
- • 3 medium cloves garlic, minced
- • Small handful fresh rosemary leaves, finely chopped
- • Freshly ground black pepper (to taste)
- • Small handful fresh parsley leaves, minced (for garnish)
Directions
- 1. Boil Potatoes: Preheat your oven to 450°F (232°C). If using a convection oven, preheat to 400°F (204°C). Place a rack in the center position. Bring 2 quarts of water to a boil in a large pot. Add about 2 tablespoons of kosher salt to the water, along with the 1/2 teaspoon baking soda. Carefully add the peeled potato chunks. Boil the potatoes for around 10 minutes, or until a fork meets little resistance in the exterior of a potato chunk (the potatoes should be almost tender but not falling apart).
- 2. Infuse Oil: While the potatoes boil, combine the 5 tablespoons of olive oil (or chosen fat) with the chopped rosemary and the minced garlic in a small saucepan. Add a few grinds of black pepper. Heat the mixture over medium heat, stirring frequently. Cook for about 2–3 minutes, until the garlic just starts to turn lightly golden (do not let it brown too much or burn). Strain the hot oil through a fine-mesh strainer into a large bowl (this will be the bowl you'll toss the potatoes in). Reserve the bits of garlic and rosemary that remain in the strainer – set them aside in a small bowl (they will be added back later).
- 3. Rough Up Potatoes: When the potatoes are done boiling, drain them well. Let them sit in the empty pot for half a minute to steam off excess moisture. Then transfer the potato chunks into the large bowl with the infused oil. Season with a pinch more salt and pepper. Toss the potatoes in the oil until they are evenly coated. Rough them up: shake the bowl vigorously or use a spoon to bash the potatoes around gently until you see a layer of thick, starchy paste coating the chunks. (This rough surface will turn into a super crispy shell in the oven.)
- 4. Roast Potatoes: Line a large rimmed baking sheet with foil or parchment for easy cleanup (optional). Transfer the oil-coated, roughed-up potatoes onto the baking sheet, spreading them out in a single layer with some space in between. Roast in the preheated oven for about 20 minutes without touching them. After 20 minutes, use a thin spatula to loosen any potatoes stuck to the tray, then flip each potato. Continue roasting for an additional 30-40 minutes, flipping and shaking the pan once or twice more during that time, until the potatoes are deep golden-brown and crispy all over. (Every oven varies, so keep an eye on them – they should be very brown and crisp on the outside.)
- 5. Finish and Serve: Transfer the hot roasted potatoes into a large mixing bowl. Add the reserved garlic and rosemary bits that you set aside earlier, along with the minced fresh parsley. Toss everything to coat, so the fried garlic/herb bits and parsley are evenly distributed on the potatoes. Taste and add a bit more salt and pepper if needed. Serve immediately while they're hot and crunchy. Enjoy!
Special Equipment
Large pot, Rimmed baking sheet, Small saucepan, Fine-mesh strainer, Thin metal spatula
Notes
- Potato varieties: Russet (US) or Maris Piper (UK) potatoes will yield the crispiest results with fluffy interiors, while Yukon Gold (US) or King Edward (UK) also work well (a bit less crisp, but more buttery flavor). It's best to avoid red potatoes here, as they tend to not crisp as well and can turn mushy.
- Potato size: Cutting the potatoes into large chunks (at least 2 inches) is crucial. For medium Yukon Golds, cutting into halves or quarters is sufficient; for large russets, cut into sixths or eighths. Bigger pieces = better contrast between a crusty exterior and creamy center.
Nutrition (per serving, approx.)
275 calories; 9g fat; 46g carbs; 5g protein
Nutritional information is an estimate and may vary based on ingredients used.