Etymology

Ancient Greeks used the word φάσηλος (phasēlos) to refer to the beans of Asian origins which were cultivated in Europe at the time.^[11] The Romans used both the Latinized phaseolus and their own faba to refer to different pre-Columbian species of beans,^[12] presumably using the word faseolus for smaller seeds like those belonging to the genus Vigna such as the black-eyed peas^[13] and the word faba for larger seeds, such as the fava beans. This latter word, faba, was related to the Proto-Germanic bauno, from which the Old English word bean is derived and has the meaning of "bean, pea, legume".^[14] When Phaseolus vulgaris arrived in Europe in the 16th Century, this species was yet another seed in a pod, thus there were already words in the European languages describing it.

P. vulgaris was known as ayacotl in the Aztec language nahuatl, búul in Mayan and purutu in the Incan language quechua. In the Americas, indigenous names for P. vulgaris were not derived from Greek/Roman roots phaselus/faseolus, as are Castilian Spanish frijol, Portuguese feijão, and Catalan fesol, but from the local languages. For example, it is called poroto in Chilean Spanish, from the Incan purutu.

Cultivars and varieties

Archeologists found large-seeded varieties of the domesticated bean in the highlands of Peru, dating to 2300 BC, and spreading to the coastal regions by around 500 BC.^[21] Small-seeded varieties were found in sites in Mexico, dating to 300 BC, which then spread north and east of the Mississippi River by 1000 AD.^[21]

Many well-known bean cultivars and varieties belong to this species, and the list below is in no way exhaustive. Both bush and running (pole) cultivars/varieties exist. The colors and shapes of pods and seeds vary over a wide range.

Nutrition

Raw green beans are 90% water, 7% carbohydrates, 1% protein, and contain negligible fat (table). In a reference amount of 100 grams (3.5 oz), raw green beans supply 36 calories, and are a rich source (20% or more of the Daily Value, DV) of vitamin K (41% DV) and a moderate source (10-19% DV) of vitamin C, vitamin B6, and manganese (table).

Dry white common beans after boiling are 63% water, 25% carbohydrates, 10% protein, and contain little fat (table). In a reference amount of 100 grams (3.5 oz), boiled white common beans supply 139 calories and are a rich source of folate and manganese, with moderate amounts of thiamine and several dietary minerals (table).

Dry beans

Dry beans will keep indefinitely if stored in a cool, dry place, but as time passes, their nutritive value and flavor degrade, and cooking times lengthen. Dried beans are almost always cooked by boiling, often after being soaked in water for several hours. While the soaking is not strictly necessary, it shortens cooking time and results in more evenly textured beans. In addition, soaking beans removes 5 to 10% of the gas-producing sugars that can cause flatulence for some people.^[49] The methods include simple overnight soaking and the power soak method, in which beans are boiled for three minutes and then set aside for 2–4 hours. Before cooking, the soaking water is drained off and discarded. 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, which is also said to aid digestion. In East Asia, a type of seaweed, kombu, is added to beans as they cook for the same purpose. Salt, sugar, and acidic foods such as tomatoes may harden uncooked beans, resulting in seasoned beans at the expense of slightly longer cooking times.^{[citation needed]}

Dry beans may also be bought cooked and canned as refried beans, or whole with water, salt, and sometimes sugar.

Green beans and wax beans

The three commonly known types of green beans are string or snap beans, which may be round or have a flat pod; stringless or French beans, which lack a tough, fibrous string running along the length of the pod; and runner beans, which belong to a separate species, Phaseolus coccineus. Green beans may have a purple rather than green pod, which changes to green when cooked.^[50] Wax beans are P. vulgaris beans that have a yellow^[4] or white pod. Wax bean cultivars are commonly grown;^[4] the plants are often of the bush or dwarf form.^[4]

As the name implies, snap beans break easily when the pod is bent, giving off a distinct audible snap sound. The pods of snap beans (green, yellow and purple) are harvested when they are rapidly growing, fleshy, tender (not tough and stringy), and bright in color, and the seeds are small and underdeveloped (8 to 10 days after flowering).

Green beans and wax beans are often steamed, boiled, stir-fried, or baked in casseroles.

Shelling beans

Shell, shelled, or shelling beans are beans removed from their pods before being cooked or dried. Common beans can be used as shell beans, but the term also refers to other species of beans whose pods are not typically eaten, such as lima beans, soybeans, peas, and fava beans. Fresh shell beans are nutritionally similar to dry beans but are prepared more like vegetables, often steamed, fried, or made into soups.^{[citation needed]}

Popping beans

The nuña is an Andean subspecies, P. v. subsp. nunas (formerly P. vulgaris Nuñas group), with round, multicolored seeds that resemble pigeon eggs. When cooked on high heat, the bean explodes, exposing the inner part in the manner of popcorn and other puffed grains.

Other uses

Bean leaves have been used to trap bedbugs in houses.^[51] Microscopic hairs (trichomes) on the bean leaves entrap the insects.^[51]

From ancient times, beans were used as devices in various methods of divination. Fortune-telling using beans is called favomancy.

P. vulgaris has been found to bio-accumulate zinc, manganese, and iron and have some tolerance to their respective toxicities, suggesting suitability for natural bio-remediation of heavy-metal-contaminated soils.^{[52][non-primary source needed]}