Potato Chips

Potato chips are essentially french fries that are all crust and no interior. The potatoes are cut into thin cross sections around 1.5 mm thick, the equivalent of just 10–12 potato cells, then deep-fried until dry and crisp. There are two basic ways of frying chips, and they produce two different textures. Cooking at a fairly constant and high oil temperature, around 350°F/175°C, heats the slices so rapidly that the starch granules and cell walls have little chance to absorb any moisture before they’re desiccated and done, in 3–4 minutes. The texture is therefore delicately crisp and fine-grained. Most packaged chips have this texture because they’re made in a continuous processor whose oil temperature stays high. On the other hand, cooking at an initially low and slowly increasing temperature, beginning around 250°F/120°C and reaching 350°F/175°C in 8–10 minutes, gives the starch granules time to absorb water, exude dissolved starch into the potato cell walls, and reinforce and glue them together. The result is a much harder, crunchier chip. This is the texture created by “kettle frying,” or cooking the slices by the batch in a vessel like an ordinary pot. The temperature of the preheated kettle drops immediately when a batch of cold potatoes is dumped in, so the potatoes cook in oil whose temperature starts low and rises slowly as the potatoes’ moisture is cooked out and the heater catches up.