A potato peeler is a metal blade attached to a metal, plastic or wooden handle that is used for peeling vegetables, usually potatoes.
There are two main varieties, the 'yorkshire' design involding the blade as an extension of a handle, in much the same was as the blade is attached to a knife. Its use involves grasping the potato in one's left hand and holding the peeler in the fingers of the right hand and the top of the potato with the thumb of the right hand. The action then involves using the fingers of the right hand to pull the peeler's blade over the skin of the potato, turning it slightly so that it digs in and removes the potato skin, in a movement towards the right thumb. This also uses the grip of the right thumb to allow the movement of the fingers of the right hand to be based on the contraction of the right hand in a claw movement which is easier to accomplish than if the movement of the right fingers were to be cotrolled by the right arm or wrist.
Note: left-handed people usually transpose the hands in the above explanation.
The other variety more closely resembles a razor, with the blade perpendicular to the handle, is used with a similar action to a razor, the potato is grasped in the left hand and the peeler in the right. One then simply drags the blade across the skin to peel it. As with any blades this should be pulled away from the body not towards for safety reasons.
The mechanical potato peeler was invented by Herman Lay in the 1920s, allowing a mass-marketed potato chip to become popular as it allowed greater quantities of potatoes to be peeled in a shorter time.
