Kale
Curly kale
Species	Brassica oleracea
Cultivar group	Acephala Group
Origin	Unknown, before the Middle Ages
Cultivar group members	Many, and some are known by other names.

Kale or boerenkool is a vegetable of the plant species Brassica oleracea. It has green or purple leaves, in which the central leaves do not form a head. It is considered to be closer to wild cabbage than most domesticated forms of vegetables.^[1]

Name[edit]

The name borecole originates from the Dutch boerenkool (farmer's cabbage), whereas kale bears semblance to the Danish, Swedish and Norwegian kål and to the German Kohl (a general term for various kinds of cabbage) and Scottish Gaelic càl (or kail,^[2] as in Kilmany Kail; a rabbit, salt pork and kail broth from Kilmany in Perth, Scotland). Some varieties can reach a height of six or seven feet; others are compact and symmetrical and of good quality for eating. Many, however, are coarse and indigestible. Most kale are either annuals or biennials, and are raised from seeds, which, in size, form, and color, resemble those of the cabbage.

Origins[edit]

Until the end of the Middle Ages, kale was one of the most common green vegetables in Europe. Curly-leaved varieties of cabbage already existed along with flat-leaved varieties in Greece in the fourth century BC.^{[citation needed]} These forms, which were referred to by the Romans as Sabellian kale, are considered to be the ancestors of modern kales. Today one may differentiate between varieties according to the low, intermediate, or high length of the stem, with varying leaf types. The leaf colours range from light green through green, dark green and violet-green to violet-brown. Russian kale was introduced into Canada (and then into the U.S.) by Russian traders in the 19th century.

During World War II, the cultivation of kale in the U.K. was encouraged by the Dig for Victory campaign. The vegetable was easy to grow and provided important nutrients to supplement those missing from a normal diet because of rationing.^[3]

Kai-lan, a separate cultivar of Brassica oleracea much used in Chinese cuisine, is somewhat similar to kale in appearance and is occasionally called "kale" in English.

In Portugal, kale is called by its original name, "Cavolo Nero" with the expression "Couve Rebela" also being used.

Red Russian kale

Cultivars[edit]

Curly-leaf kale

Kales can be classified by leaf type:

• Curly-leaved (Scots Kale; Blue Curled Kale)
• Plain-leaved
• Rape kale
• Leaf and spear (a cross between curly-leaved and plain-leaved kale)
• Cavolo nero (also known as black cabbage, Tuscan Cabbage, Tuscan Kale, Lacinato and dinosaur kale)

Because kale can grow well into winter, one variety of Rape Kale is called Hungry Gap, named after the period in winter in traditional agriculture when little else could be harvested.

An extra-tall variety is known as Jersey kale or cow cabbage.^[4]

Nutritional value[edit]

In a 100 gram serving, raw kale provides 49 calories and is a rich source (> 19% of the Daily Value, DV) of vitamin A, vitamin C, vitamin K, vitamin B6, folate and manganese (table, raw kale). Kale is a good source of thiamin, riboflavin, pantothenic acid, vitamin E and several dietary minerals, including iron, calcium, potassium and phosphorus (table, raw kale).

Boiling raw kale diminishes these nutrient contents, with the exception of vitamin K (table, boiled kale).

Phytochemicals[edit]

Kale is a source of the carotenoids, lutein and zeaxanthin (tables).^[5]

Kale, as with broccoli and other cruciferous vegetables, contains glucosinolate compounds which contribute to formation of sulforaphane.^[6] Boiling decreases the level of sulforaphane, whereas steaming, microwaving or stir frying does not result in significant loss.^[7]

Culinary uses[edit]

A traditional New Years Danish dish; boiled ham, glazed potatoes and stewed kale.

Making Kale chips in Lockport, Illinois

Kale freezes well and tastes sweeter and more flavourful after being exposed to a frost.^[8] Tender kale greens can provide an intense addition to salads, particularly when combined with other such strongly flavoured ingredients as dry-roasted peanuts, soy sauce-roasted almonds, red capsicum flakes, or a sesame-based dressing.^{[citation needed]} When combined with oils or lemon juice, kale's flavor is noticeably reduced.^[9] When baked or dehydrated, kale takes on a consistency similar to that of a potato chip. Curly kale varieties are usually preferred for chips.^{[citation needed]} The chips can be seasoned with salt or other spices.

Regional culinary uses[edit]

In the Netherlands, it is very frequently used in a traditional winter dish called "stamppot", which is a mix of any variety of vegetables and mashed potatoes, sometimes with fried bits of bacon added to it, and usually served with rookworst ("smoked sausage").

In Ireland, kale is mixed with mashed potatoes to make the traditional dish colcannon. It is popular on Halloween when it is sometimes served with sausages. Small coins are sometimes hidden inside as prizes.

In Italy, cavolo nero is an ingredient of the Tuscan soup ribollita.

A variety of kale, kai-lan, is a popular vegetable in China, Taiwan, and Vietnam, where it is commonly combined with beef dishes.

Children collecting leaves of red Russian kale (Brassica napus L. subsp. napus var. pabularia (DC.) Alef.) in a family vegetable garden.

A traditional Portuguese soup, caldo verde, combines pureed potatoes, diced kale, olive oil, broth, and, generally, sliced cooked spicy sausage. In Brazil, where it was introduced by the Portuguese, it is an indispensable side dish for the national stew feijoada.

In the eastern African Great Lakes region, it is an essential ingredient in making a stew for ugali, which is almost always eaten with kale. Kale is also eaten throughout southeastern Africa, where it is typically boiled with coconut milk and ground peanuts and is served with rice or boiled cornmeal.

In Italy, kale (cavolo nero) is part of many dishes, such as "casseoula" (pork stew), polenta (corn porridge) with kale, Parmesan cheese and olive oil and "pizzoccheri", buckwheat tagliatelle served with kale, melted fontina cheese and potatoes.^[10]

A whole culture around kale has developed in northern Germany, especially around the towns of Bremen, Oldenburg and Hannover and the region of Dithmarschen. There, most social clubs of any kind will have a Grünkohlessen or Kohlfahrt ("kale tour") sometime between October and February, visiting a country inn to consume large quantities of kale stew, Pinkel sausage, Kassler, Mettwurst and Schnapps. These tours are often combined with a game of Boßeln. Most communities in the area have a yearly kale festival which includes naming a "kale king" (or queen).

Curly kale is used in Denmark and southwestern Sweden (Scania, Halland and Blekinge) to make (grøn-)langkål (Danish) or långkål (Swedish), an obligatory dish on the julbord in the region, and is commonly served together with the Christmas ham (Sweden). The leaves of the kale are separated from the stem, and then boiled with stock. The result is drained and pressed to remove the remaining liquid. The kale can now be frozen for up to 6–8 months if needed. To make langkål, finely chop the (defrosted) kale and fry it with cream, pepper, and syrup (or sugar) for sweetening.^[11] In Sweden, it is also commonly eaten as a soup, with a base of ham broth and the addition of onion and pork sausages.

In Scotland, kale provided such a base for a traditional diet that the word in dialect Scots is synonymous with food. To be "off one's kail" is to feel too ill to eat.

In Montenegro, collards, kale, locally known as rashtan, is a favorite vegetable. It is particularly popular in the winter, cooked with smoked mutton (kastradina) and potatoes.

In the Southern United States, kale is often served braised, either alone or mixed with other greens, such as collard, mustard, or turnip. It is also used in salads. Flavored kale chips have also been produced as a potato chip substitute.^[12]

In Japan, kale juice (known as aojiru) is a popular dietary supplement.

In Turkey, especially in Eastern Black Sea Region, kale soup (karalahana çorbası), kale sarma, kale kavurma (sauté), kale turşu are all very common and popular dishes.

Decorative uses[edit]

Ornamental kale

Many varieties of kale and cabbage are grown mainly for their ornamental leaves, which are brilliant white, red, pink, lavender, blue or violet in the interior of the rosette. Ornamental kale is as edible as any other variety.^[13]

Literature[edit]

The Kailyard school of Scottish writers, which included J. M. Barrie (creator of Peter Pan), consisted of authors who wrote about traditional rural Scottish life (kailyard = kale field). In Cuthbertson's book Autumn in Kyle and the charm of Cunninghame, he states that Kilmaurs in East Ayrshire, was famous for its kale which was an important foodstuff. A story is told in which a neighbouring village offered to pay a generous price for some kale seeds, an offer too good to turn down. The locals agreed; however a gentle roasting on a shovel over a coal fire ensured that the seeds never germinated.^[14]

See also[edit]

• Bowen's Kale
• Crambe maritima - Sea Kale
• Dimethyl tetrachloroterephthalate

References[edit]

• Dr. D. G. Hessayon: The Vegetable & Herb Expert. Expert Books (2003). ISBN 0-903505-46-0.

External links[edit]

• Marrow-Stem Kale – Plants For a Future database
• PROTAbase on Brassica oleracea (leaf cabbage)