At the shelling company buying station, peanuts are sampled and graded by the Federal-State Inspection Service to determine their value. The inspectors establish the meat content, size of pods, kernel size, moisture content, damaged kernels and foreign material. The results of the inspection determine the overall quality and value of each load.
After the peanuts are purchased by the sheller, they are placed in dry storage for eventual sale to processors and manufacturers. At the shelling plant, peanuts are taken from storage and cleaned; dirt, rocks, bits of vines and other debris are removed. If they are to be sold in their shells, the peanuts may also pass through a machine that cuts off any remaining stems on the shells. (About 10% of the peanut crop is sold as in-shell peanuts - usually the Virginia and Valencia types.) To sort for size, the peanuts travel over sizing screens that permit the smaller pods to fall through.
Peanuts to be shelled are placed in slotted drums containing screens of different sizes. Rotating peanuts rub against each other until the shells are opened and the kernels fall out. The kernels are sized on screens that permit the smaller kernels to fall through. The shelled peanuts are cleaned again to remove foreign materials. This is done with density separators, electronic color sorters and by visual inspection to ensure that only the best peanuts reach the market. The peanut kernels are then sized, graded and bagged for market.
From the sheller, peanuts are cleaned again and "blanched" before they are used in most peanut foods. Blanching is simply the removal of the reddish skin covering the kernels. In whole-nut or split-nut dry blanching, the kernels travel through warm air for a period of time to loosen the skins. Then the kernels go through a blanching machine where large rollers rub the surfaces of the kernels until the skins fall off. These kernels are checked with electronic color sorters to ensure that blanching is complete.