To dry beans, leave the drying pods on the plant until they are brown, dry and rattling, or pluck the beans and spread them in sunlight. If the weather is expected to be wet or frosty, pluck the pods, and hang them on a string in a dark, dry, airy room; spread them in a store-bought dehydrator; or heat them in an oven.
Beans that are dried in open sunlight should not be left outdoors all day, or they may form crusts on the outside that prevent the inside from drying adequately. They should also be covered with a nylon cloth netting to shield them from pests and airborne debris and stirred regularly to ensure they dry evenly.
When drying beans by the oven method, put the oven on the warm setting, leave the door ajar, and turn it off when it gets too hot to prevent the beans from burning, cooking or caramelizing. Avoid placing the trays on the upper element of the oven, and rotate them regularly for even drying. Never use tray frames made of copper, aluminum, galvanized metal or nonfood-grade plastic, since they tend to get too hot.
To test if the beans are dry, squeeze them between the thumb and fingernail. Dry beans are hard, do not leave an imprint, and are glossy. Shell the pods, winnow out debris, and remove any shriveled beans before packing them in dry, airtight containers. It is advisable to condition and pasteurize them before storage if pests have infested them, or store the containers in the freezer if there is a high chance of pest infestation. The seeds should remain viable for at least four years if stored correctly.