The Instant Fries* Formula
(or how fast-food chains make millions of "French fries" identical)
In order to guarantee a consistent taste and quick prep time, a fast-food chain puts all of its potatoes through the same preparation process:
Even before any potatoes have even been planted, the company agrees to buy a farmer's entire crop. It also specifies the type of potatoes and their growing conditions, which include soil treatment and fertilizers. Specific varieties, such as Majestic, Maris Piper, or the Pentland Series, are selected for their keeping quality. Potatoes that are large and round in shape are preferred because they are clean, easy to peel, and little is wasted.
After harvest, the potatoes are loaded into refrigerated storage at 48 to 50 degrees farenheit, or 9 to 10 degrees celcius, in the dark. They are regularly inspected for freshness under these conditions. Potatoes are again inspected and weighed at the potato processing plant. The density of potatoes is an important factor, as it indicates whether potatoes have become soft inside. They are passed over sieves to remove any dirt and debris, and magnets and electronic detectors are used to remove any metal particles. After the potatoes have been washed, the skins are softened with alkali and removed with steam.
Next, potatoes are sliced into square-sectioned strips. Thin strips will cook faster but will become hard if overcooked (like the ones remain at the bottom after you've eaten). The ideal size for most fast-food restaurants is a cross-section of about 1/4 inch (6mm). The cut potato strips are blanched on a wire-mesh conveyor belt which passes them through a tank of hot water or a dilute solution of phosphate or citrate salt. This helps prevent discoloring. The cut potatoes are finally frozen, bagged, and packed into cartons and kept at -4F (-20C) until collected for delivery to the fast-food outlets in refrigerated vans.
Within just minutes of being removed from the McDonald's freezer, a bagful can be soaked in lard, deep fried, and ready for you to eat. Yum.
*called chips in some other parts
adapted from Reader's Digest's How in the World?