When comparing a food processor and a grinder, consumers will find differences in the texture and size of the processed food, as well as in which foods work and how the cutting mechanisms are fitted. Most of the time, people should not use food processors as grinders and vice versa. Some overlap exists, however, so depending on exactly what the individual wants to make and the design of the device, it sometimes is possible to interchange the two.
The main difference between a food processor and a grinder is the result of the foods run through the devices. A food processor normally chops, grates or slices. As the name of the tool implies, a food grinder, by comparison, cuts, crushes and mashes the food, forming a mushy or very fine product that doesn't always have clear pieces.
The difference in how a food processor and a grinder work mean that food grinders are better for making pastes, spreads or patties. For instance, some models grind meat for hamburger patties or sausage well. Other grinders are excellent for grinding grains, herbs or beans, such as one might do for coffee, seasonings or flour. A food processor, by comparison, is good for things such as potato salads, stuffing, or shredded cheeses.
Understanding that a food processor and a grinder are designed to work with different foods and to produce a different end result, the two devices are very different in design. With meat grinders, the device has a chute or hopper into which the chef deposits the meat. A sharpened screw guides the meat toward a series of blades, which then cut it and guide it through a screen. Grain, herb and nut grinders work basically the same way, but they may have a set of burr plates instead of rotating blades, and they typically have additional parts to sort and filter. Some grinders, similar to some processors, operate via a crank system.
A food processor either has stationary, pump-based or rotating blades. Ones with stationary blades require the chef to guide the food over the blade, after which it falls into the main processor container. Pump blades connect to a handle within the processor lid, moving up and down as the chef lifts and presses the pump. Rotating blades are connected to a crank mechanism within the lid; they turn within the container as the chef turns the crank.
Even though differences exist within a food processor and a grinder, some overlap also is present. For example, some electric food processors have "grind" settings. It's not uncommon for people to use a food processor to make "pasty" products such as pastry dough, and many people grind meat in food processors. Ultimately, the difference boils down to the blade setup and whether the blades cut finely enough to create the desired texture.