Blanch your fries in a baking soda and sugar solution.
Using baking soda promotes the breakdown of pectin, whereas vinegar promotes the maintenance of its integrity; thus baking soda chips will have a softer, fluffier interior due to the potato flesh being broken down more completely during the blanching step, and vinegar chips will be more durable for handling and frying but not as tasty. In addition, alkaline conditions also favor browning via the Maillard reaction and the sugar enhances browning as well as complementing the potato taste. Acidic conditions tend to inhibit browning.