French fries are served hot, either soft or crispy, and are generally eaten as part of lunch or dinner or by themselves as a snack, and they commonly appear on the menus of diners, fast food restaurants, pubs, and bars. Fries in America are generally salted and are almost always served with ketchup, but in many countries they have other condiments or toppings, like vinegar, mayonnaise, or other local specialties. Fries can be topped more heavily, as in the dishes of poutine and chili cheese fries. French fries can be made from sweet potatoes instead of potatoes. A baked variant of the French fry ("chunky oven chips") uses less or even no oil.

​

French fries are prepared by first peeling and cutting the potato into even strips. These are then wiped off or soaked in cold water to remove the surface starch, and thoroughly dried. They may then be fried in one or two stages. Chefs generally agree that the two-bath technique produces better results.

​

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 may 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 2–3mm strips, the first bath takes about 3 minutes, and the second bath takes only seconds.

​

Most French fries are produced from frozen potatoes which have been blanched or at least air-dried industrially. The usual fat for making French fries is vegetable oil. In the past, beef suet was recommended as superior, with vegetable shortening as an alternative. In fact, McDonald's used a mixture of 93% beef tallow and 7% cottonseed oil until 1990, when they switched to vegetable oil with beef flavouring.

​

Thomas Jefferson had "potatoes served in the French manner" at a White House dinner in 1802. The expression "French fried potatoes" first occurred in print in English in the 1856 work Cookery for Maids of All Work by E. Warren: "French Fried Potatoes. – Cut new potatoes in thin slices, put them in boiling fat, and a little salt; fry both sides of a light golden brown colour; drain." It is apparent that this account refers to thin, shallow-fried slices of potato – it is not clear where or when the now familiar deep-fried batons or fingers of potato were first prepared. In the early 20th century, the term "French fried" was being used in the sense of "deep-fried" for foods like onion rings or chicken. It is unlikely that "French fried" refers to frenching in the sense of julienning, which is not attested until after French fried potatoes. Previously, frenching referred only to trimming meat off the shanks of chops.