The common bean is a herbaceous annual plant grown worldwide for its edible dry seeds.
It is a seed of certain leguminous plants of the family Fabaceae.
The common bean is a highly variable species that has a long history of cultivation.
The cultivated common bean was domesticated about 8,000 years ago.
It was originally believed that it had been domesticated separately in Mesoamerica and in the southern Andes region, giving the domesticated bean two gene pools. However, recent genetic analyses show that it was actually domesticated in Mesoamerica first, and traveled south, probably along with squash and corn.
Beans were also carried into North America and were grown by Native Americans there for many centuries.
They were carried to Europe by early explorers of the New World, and have undergone about 500 years of additional domestication and selection in Europe.
There are many varieties of the common bean.
Some varieties of the common bean are grown only for the dry seeds, some only for the edible immature pods [photo below], and others for the seeds, either immature or mature.
Beans are grown on every continent except Antarctica.
Bush varieties form erect bushes from 20 to 60 cm (8 to 20 in) tall, while pole or running varieties form vines from 2 to 3 m (7 to 10 ft) long.
All varieties bear alternate, green or purple leaves, which are divided into three oval, smooth-edged leaflets, each 6 to 15 cm (2 to 6 in) long and from 3 to 11 cm (1 to 4 in) wide.
The white, pink, or purple flowers are about 1 cm long, and they give way to pods from 8 to 20 cm (3 to 8 in) long and 1 to 1.5 cm (0.4 to 0.6 in) wide.
The pods may be green, yellow, black, or purple in color, each containing 4–6 beans.
The beans are smooth, plump, kidney-shaped, up to 1.5 cm long, range widely in color, and are often mottled in two or more colors.
Similar to other beans, the common bean is high in starch, protein, and dietary fiber, and is an excellent source of iron, potassium, selenium, molybdenum, thiamine, vitamin B6, and folate.
The toxic compound phytohaemagglutinin, a lectin, is present in many common bean varieties. This toxin can be removed by boiling the beans for at least 30 minutes at 100°C. If the beans are cooked in slow cooker (80°C for a longer time) danger of poisoning can be increased five times and this method of preparation of beans is not recommended.
Dry common beans take longer to cook than most pulses: cooking times vary from one to four hours, but are substantially reduced with pressure cooking.
In Mexico, Central America, and South America, the traditional spice used with beans is epazote.
In East Asia, a type of seaweed, kombu, is added to beans as they cook for the same purpose.
The word “Bean” originally meant the seed of the broad bean, but was later broadened to include members of the genus Phaseolus such as the common bean and the runner bean, and the related genus Vigna. The term is now applied in a general way to many other related plants, such as soybeans, peas, lentils, vetches, and lupines.
The common bean is second to the soybean in importance.
The three Mesoamerican crops constitute the “Three Sisters” central to indigenous North American agriculture.
From ancient times, beans were used as device in various methods of divination. Fortune-telling using beans is called favomancy.
In the 6th century BC, Pythagoras had a deep philosophical dislike of beans, believing that they contained the souls of the dead. He is said to have allowed himself to be slaughtered rather than cross a field of beans.
In ancient Greece minor officials were elected by putting one white and many black beans in a pot. Whoever picked the white bean got the job.
In the 19th century the Russian army used a similar system to give a conscript his freedom.