By Harold McGee
“French fries” may first have been made in significant quantities by Parisian street vendors early in the 19th century. They are potato sticks cut with a square cross section, 5–10 mm on a side, deep-fried in oil, with a crisp gold exterior and a moist interior that’s fluffy if the potatoes are high-starch russets, creamy otherwise. Simple quick frying doesn’t work very well; it gives a thin, delicate crust that’s quickly softened by the interior’s moisture. A crisp crust requires an initial period of gentle frying, so that starch in the surface cells has time to dissolve from the granules and reinforce and glue together the outer cell walls into a thicker, more robust layer.