A shell bean is any kind of bean that is grown and harvested for the seeds rather than the pods. Green beans, for example, are not considered a shell bean because they are harvested for their pods as well as for their seeds. Black beans and garbanzo beans — which are also sometimes called chick peas — are both examples of shell beans because the pod that the seeds grow in are discarded when the legumes are harvested and the seeds themselves are saved to be used in salads, soups, stews, dips, and any other number of dishes that call for the beans.
There are many different types of shell beans. Lima beans, butter beans, broad beans, fava beans, black beans, blackeyed peas, and many others are considered shell beans. The nearly endless varieties of these legumes can be used in myriad dishes from cuisines around the world.
The term "shell bean" is often used to refer to a bean that has been freshly removed from its pod. This means that the bean has not been canned or dried. Canned beans can usually be cooked in a manner that is similar to the ways in which shell beans can be cooked. However, the fresh beans and the beans that have been stored in a can will usually have a slightly different flavor. Beans that have been dried, on the other hand, may need to be soaked for up to 24 hours before they are hydrated enough to cook with and, even after this period of rehydration, may still be a bit more "al dente" than the fresh and canned versions of the same bean.
One unusual example of the shell bean is the green soy bean as it is prepared for edamame, which is a Japanese dish. Although the seed pod is not eaten, the entire bean, including the pod and the seeds, is cooked and served intact. The green soy beans are usually boiled or steamed and then served with a sprinkling of crushed sea salt. In order to eat edamame, the seed pod is squeezed between the teeth so that the seeds pop into the mouth and then the shell is discarded. This is a kind of shell bean where the shelling is done after the legumes have been cooked instead of before, which is the most common method.