Wash potatoes, and cut into even sticks, skin on. Keeping the size of the fries as uniform as possible will aid in even cooking.
Soak potatoes in a bowl of cold water to cover, for a minimum of 1 hour.
Pat potatoes completely dry with paper towels.
Heat oil to 275-300 and fry potatoes in batches until they have softened but not started to brown or crisp.
Increase heat to 400.
Return partially cooked fries to oil and fry until brown and crisp.
Drain again on paper towels and sprinkle immediately with sea salt.