Russet potato skins are high in starch, which seals in moisture. When baked, grains beneath the skin absorb moisture, expand, and separate to gain a fluffy texture.
Score a potato before baking by cutting an X about a quarter of an inch deep into the potato's top, allowing the steam to escape through it during the baking process.
By baking your potatoes directly on your oven rack, the heat in the oven circulates evenly around them, ensuring ultimate crispiness all the way around.
Position the rack in the oven's middle, where hot air flows most consistently. You can also place a wire rack on the baking sheet and cook on top of it to achieve the same effect.
Start with a preheated baking sheet so the entire potato starts cooking evenly and immediately, as the bottom won't have to wait for the sheet to heat up.
Brine potatoes in salt water for six hours before baking so the potato skins dry out, allowing the starches to break down and making the skins extra crunchy.
You can further coat the spuds in more kosher and seasoned salt before baking to keep the moisture from the brine in the potatoes and give the outside a crave-worthy crunch.