Bake a potato at 205°C (400°F) for 60–75 minutes for a medium-sized russet (225–280 g), or until the internal temperature reaches 98°C (208°F) and a knife slides through the centre with zero resistance. This is the correct method for a baked potato with crisp, salted skin and a dry, fluffy interior that shatters into starchy clouds when split open. Wrapping in foil is not baking — it is steaming, and it produces a wet, dense, gluey potato that no amount of butter can rescue. The variety matters absolutely. Russet Burbank is the standard for baked potatoes — its high starch content (20–22%) and low moisture create the dry, mealy texture that defines the style. Yukon Gold, a medium-starch waxy-floury hybrid, bakes adequately but produces a creamier, denser interior that lacks the dramatic fluffiness. Red-skinned potatoes and fingerlings are waxy varieties with high moisture and low starch — they are wrong for baking and right for roasting and boiling. If you cannot get Russets, look for King Edward or Maris Piper in the UK, or Kennebec in speciality markets. The method is simple but unforgiving. Scrub the potatoes under cold water and dry them thoroughly — moisture on the skin turns to steam and prevents crisping. Rub the entire surface with a thin film of olive oil or vegetable oil, then coat generously with flaky salt — kosher salt or Maldon. The oil conducts heat into the skin more efficiently than dry air alone, and the salt draws out surface moisture while the potato bakes, creating a micro-crust that crackles when you press it. Pierce each potato four to six times with a fork or paring knife to allow steam to escape; without venting, pressure can build and — rarely but memorably — cause the potato to burst. Place directly on the oven rack, with a sheet pan on the rack below to catch any drips. Do not use a baking sheet under the potato — contact with the flat surface steams the bottom skin, making it soggy. At 205°C, the exterior dehydrates and the Maillard reaction browns the skin's natural sugars and amino acids. Meanwhile, the interior starch granules absorb the potato's own moisture, swell, and burst — this is gelatinisation followed by retrogradation as the steam escapes, and it is what creates that airy, fluffy texture. This is where the dish lives or dies: the moment you split the potato. Immediately upon removing from the oven, cut a deep cross into the top and squeeze the ends toward each other. The starchy interior erupts upward into a rough, craggy surface with enormous surface area — this is where butter melts into every crevice, where sour cream clings, where chives and black pepper find purchase. If you slice it flat and press it open, you compress the starch, lose the fluff, and reduce the surface area by half. The squeeze is not optional. The quality hierarchy: (1) A competent baked potato is cooked through with no hard centre. (2) A great baked potato has skin that is crisp enough to audibly crackle when pressed, salted so thoroughly that each bite of skin is seasoned, with an interior so fluffy it resembles dry mashed potatoes before any butter is added. (3) A transcendent baked potato — and this method comes from the salt-crust school — is buried entirely in a bed of coarse salt (roughly 1 kg per potato), baked at 205°C for 90 minutes. The salt insulates and dehydrates simultaneously. The skin becomes a shell — tap it and it sounds hollow like terracotta. The interior is impossibly dry and fluffy, seasoned from the outside in. Brush off the salt and the potato is not over-salted — the skin acts as a barrier. Sensory tests: a fully baked potato, when squeezed with an oven mitt, yields easily and completely — no firm core. The skin should feel papery and taut, not soft or rubbery. The aroma is earthy and faintly sweet. If you detect a wet, starchy smell, the potato is undercooked.
Starch content determines baking success. High-starch potatoes (Russet, Kennebec) have large starch granules that swell dramatically during cooking, pushing cells apart and creating a light, mealy texture. Low-starch waxy potatoes (Red Bliss, Charlotte, Fingerling) hold their shape because their smaller starch granules do not swell as much — excellent for potato salad, wrong for baking. Dry heat is the principle. Everything about the method serves dehydration: the oil promotes heat transfer, the salt draws moisture, the oven rack allows air circulation, the fork holes vent steam. Any departure — foil, baking sheet, microwave — introduces moisture and undermines the entire goal. The 98°C (208°F) internal target is specific for a reason. Starch gelatinisation in potatoes is complete by 95°C. The additional degrees ensure that enough moisture has escaped as steam to leave the interior fluffy rather than gummy. Below 95°C, you have a mealy, under-gelatinised centre. Above 100°C, you are boiling the interior water and the potato is collapsing.
For loaded baked potatoes, prepare the toppings while the potato bakes: crisp bacon in a cold pan over medium heat until rendered and shatteringly crunchy (12–15 minutes), grate sharp cheddar on a box grater (pre-shredded cheese contains anti-caking agents that prevent proper melting), slice scallions thinly, and bring sour cream to room temperature so it melts on contact. For twice-baked potatoes, scoop the interior into a bowl, mix with butter, cream, cheese, and seasoning, pipe back into the skin, and bake at 220°C (425°F) for 15 minutes until the top is golden. For the best possible jacket potato in the British style, bake as described, then split, add a generous knob of salted butter, and serve with a simple filling of baked beans (Heinz, warmed, never microwaved) and grated mature cheddar — the combination of starchy potato, sweet beans, and sharp cheese is as perfect a trinity as exists in comfort food.
Wrapping in aluminium foil, which traps steam and produces a steamed potato with limp, chewy skin — the single most common error. Second: baking at too low a temperature. At 175°C (350°F), the potato takes 90 minutes and the skin never crisps properly because the dehydration rate is too slow. Third: not oiling and salting the skin, which leaves it bland and leathery rather than flavourful and crisp. Fourth: piercing the potato too few times — one or two holes may not vent enough steam, especially with large potatoes. Fifth: cutting the potato open with a lateral slice and pressing flat, which destroys the fluffy texture. Always cross-cut and squeeze.