Fill the deep fryer with the oil up to the maximum level, Turn the deep fryer on to 160°
Peel and chop potatoes into strips, dry with paper towel. When the red dot next to the temperature has stopped flashing it has come to temperature. Have a dish next to the deep fryer ready lined with paper towel. Fry the potatoes for 7 minutes (you may have to do two batches). The idea of twice fried potatoes is that you cook them without colouring. When cooked place into the dish lined with paper towel.
Turn the deep fryer up to 190° once again, when the red dot has stopped flashing, start cooking the potatoes for the second time, this time the very hot oil will give them colour and also make them crunchy, this will take 2 minutes.
Drain onto paper towel again and season with salt.