According to OceanSpray.com, the earliest cranberries were hand picked. Then harvesters began using wooden tools to remove berries from vines. Harvesting cranberries has evolved since then.
The most common form of harvesting cranberries is wet harvesting, according to the Ocean Spray website. The bog is flooded with up to 18 inches of water, causing cranberries to float to the surface. Water reels are used to loosen the berries. The berries then rise to the top of the water and are gathered by people walking through the bogs. Cranberry juice and cranberry sauce are made from berries harvested using the wet-harvesting method.
Fresh berries sold in the produce section of your supermarket are harvested by using the dry method. A machine is used to pull the berries from vines and gather them into a sack attached to the machine.