Peel and rinse the potatoes. Then cut them into the desired shape; the thinner the shape, the faster they'll cook.
Place them in a large bowl of cold water for 2/3 hours. Alternatively you can place them in a bowl of water and in the fridge overnight.
When you're ready to cook turn the deep fryer on and, dry the fries off with a paper towel otherwise you'll burn your house down.
Drop in a few potatoes at a time into the hot oil until they're soft. Remove each batch onto a paper towel and blot to remove excess oil. 4 to 5 minutes depending on your fryer.
Once you've done all the fries, do it all again to get a crispier fry.
Sprinkle with sea salt and serve.