How Does a Food Processor Work?

DRW and Associates, Inc.

Food processors are one of the first small appliances that kids moving out on their own think of when it comes to outfitting a kitchen. It's hard to believe that when our parents were children, processors like microwave ovens, weren't at all common. The first processor, invented by French catering salesman Pierre Verdan, used the general idea behind blenders seen in bars and malt shops since the 1920s. It was designed for preparing foods, not blending liquids, and was marketed to restaurants by Robot Coupe of France beginning in the 1960s. Machines were heavily weighted in the base to keep the machine from "walking" on a counter. An induction motor turned a vertical shaft upon which rested an extremely sharp Sabatier S-shaped steel blade. The machine saved time and endless knife sharpening for sous-chefs and kitchen helpers. Verdan introduced a domestic version of the Robot Coupe to England as the Magimix in 1972. If the design of the Robot Coupe sounds familiar, that's because an American, Carl Sontheimer, began selling a home version with a clear plastic bowl in the U.S. in 1974. He called it the Cuisinart food processor. The original machines were rugged---thousands of Magimix 1800's and original Cuisinarts are still in service.

Today's food processors still use Verdan's basic design. A heavy motor drives a vertical shaft that turns a blade to chop, blend or puree food, depending on the length of operation. The position of the blade is low, using gravity to keep chopping large, heavier pieces while the smaller pieces rise or drift to the sides of the bowl. The action is started and stopped, or pulsed, repeatedly to allow for contents shifting as the blade chops, making finer chops as the pulses continue. Continuous operation pulverizes or purees foods. Accessory blades have been added, including blades for shredding and slicing that are mounted close to the top of the bowl to process food lowered through an opening. This opening is generally built into a sort of tower and a removable "pusher" keeps fingers away from the sharp blade. All cutting attachments are made of steel except dough blades and egg white blades which are generally plastic. The towers and pushers have holes in the bottoms for adding liquids to the food.

Since the blades are so sharp, food processors are built with the type of safety features not found in many small appliances until quite recently. The first machines had one speed with two choices---"pulse" and "on." Today's processors may have a choice of speeds but generally have "off" and "on" switches for each speed. The motors have trip switches that prohibit operation if the bowl and lid are not properly seated. Machines are available from a number of makers and in a number of sizes from a one or two cup mini used to chop a bit of onion for a recipe to large 12 to 15 cup bowls for whole holiday dinner dishes.