In the two-stage or two-bath method, the first bath, sometimes called blanching, is in hot fat (around 160 °C / 320 °F) to cook them through. This step can be done in advance. Then they are more briefly fried in very hot fat (190 °C / 375 °F) to crisp the exterior. They are then placed in a colander or on a cloth to drain, salted, and served. The exact times of the two baths depend on the size of the potatoes. For example, for 2–3 mm strips, the first bath takes about 3 minutes, and the second bath takes only seconds. One can cook french fries using several techniques. Deep frying submerges food in hot fat, most commonly oil. Vacuum fryers are suitable to process low-quality potatoes with higher sugar levels than normal, as they frequently have to be processed in spring and early summer before the potatoes from the new harvest become available. In the UK, a chip pan is a deep-sided cooking pan used for deep-frying. Chip pans are named for their traditional use in frying chips.