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Flax, also known as common flax or linseed, is a flowering plant, ''Linum usitatissimum'', in the family
Linaceae Linaceae is a family of flowering plants. The family is cosmopolitan, and includes about 250 species in 14 genera, classified into two subfamilies: the Linoideae and Hugonioideae (often recognized as a distinct family, the Hugoniaceae). Leaves of ...
. It is cultivated as a food and
fiber crop Fiber crops are field crops grown for their fibers, which are traditionally used to make paper, cloth, or rope. Fiber crops are characterized by having a large concentration of cellulose, which is what gives them their strength. The fibers may b ...
in regions of the world with temperate climates. Textiles made from flax are known in Western countries as
linen Linen () is a textile made from the fibers of the flax plant. Linen is very strong, absorbent, and dries faster than cotton. Because of these properties, linen is comfortable to wear in hot weather and is valued for use in garments. It also ...
and are traditionally used for bed sheets, underclothes, and table linen. Its oil is known as
linseed oil Linseed oil, also known as flaxseed oil or flax oil (in its edible form), is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant (''Linum usitatissimum''). The oil is obtained by pressing, sometimes followed by ...
. In addition to referring to the plant, the word "flax" may refer to the unspun fibers of the flax plant. The plant species is known only as a cultivated plant and appears to have been domesticated just once from the wild species ''
Linum bienne ''Linum bienne'', the pale or narrowleaf flax, is a flowering plant in the genus ''Linum'', native to the Mediterranean region and western Europe, north to England and Ireland. Pale flax grows as a biennial plant, biennial or perennial plant i ...
'', called pale flax. The plants called "flax" in New Zealand are, by contrast, members of the genus '' Phormium''.


Description

Several other species in the genus ''Linum'' are similar in appearance to ''L. usitatissimum'', cultivated flax, including some that have similar blue flowers, and others with white, yellow, or red flowers. Some of these are perennial plants, unlike ''L. usitatissimum'', which is an
annual plant An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. The length of growing seasons and period in which they take place vary according to geographical ...
. Cultivated flax plants grow to tall, with slender stems. The
leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...
are
glaucous ''Glaucous'' (, ) is used to describe the pale grey or bluish-green appearance of the surfaces of some plants, as well as in the names of birds, such as the glaucous gull (''Larus hyperboreus''), glaucous-winged gull (''Larus glaucescens''), g ...
green, slender lanceolate, 20–40 mm long, and 3 mm broad. The flowers are pure pale blue, 15–25 mm in diameter, with five petals. The fruit is a round, dry capsule 5–9 mm in diameter, containing several glossy brown seeds shaped like an apple pip, 4–7 mm long.


History

The earliest evidence of humans using wild flax as a textile comes from the present-day
Republic of Georgia A republic () is a "state in which power rests with the people or their representatives; specifically a state without a monarchy" and also a "government, or system of government, of such a state." Previously, especially in the 17th and 18th c ...
, where spun, dyed, and knotted wild flax fibers found in Dzudzuana Cave date to the Upper Paleolithic, 30,000 years ago. Humans first domesticated flax in the Fertile Crescent region. Evidence exists of a domesticated oilseed flax with increased seed-size from Tell Ramad in
Syria Syria ( ar, سُورِيَا or سُورِيَة, translit=Sūriyā), officially the Syrian Arab Republic ( ar, الجمهورية العربية السورية, al-Jumhūrīyah al-ʻArabīyah as-Sūrīyah), is a Western Asian country loc ...
and flax fabric fragments from Çatalhöyük in Turkey by years ago. Use of the crop steadily spread, reaching as far as
Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...
and Germany by 5,000 years ago. In China and India, domesticated flax was cultivated at least 5,000 years ago. Flax was cultivated extensively in ancient Egypt, where the temple walls had paintings of flowering flax, and mummies were embalmed using linen. Egyptian priests wore only linen, as flax was considered a symbol of purity. Phoenicians traded Egyptian linen throughout the Mediterranean and the Romans used it for their
sail A sail is a tensile structure—which is made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may ...
s. As the Roman Empire declined, so did flax production. But with laws designed to publicize the hygiene of linen textiles and the health of linseed oil, Charlemagne revived the crop in the eighth century CE.Wisseman S., p.125 Eventually, Flanders became the major center of the European linen industry in the Middle Ages. In North America, colonists introduced flax, and it flourished there, but by the early 20th century, cheap cotton and rising farm wages had caused production of flax to become concentrated in northern Russia, which came to provide 90% of the world's output. Since then, flax has lost its importance as a commercial crop, due to the easy availability of more durable fibres.


Uses

Flax is grown for its seeds, which can be ground into a meal or turned into
linseed oil Linseed oil, also known as flaxseed oil or flax oil (in its edible form), is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant (''Linum usitatissimum''). The oil is obtained by pressing, sometimes followed by ...
, a product used as a nutritional supplement and as an ingredient in many wood-finishing products. Flax is also grown as an ornamental plant in gardens. Moreover, flax fibers are used to make
linen Linen () is a textile made from the fibers of the flax plant. Linen is very strong, absorbent, and dries faster than cotton. Because of these properties, linen is comfortable to wear in hot weather and is valued for use in garments. It also ...
. The
specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
in its species name, ''usitatissimum,'' means "most useful". Flax fibers taken from the stem of the plant are two to three times as strong as cotton fibers. Additionally, flax fibers are naturally smooth and straight. Europe and North America both depended on flax for plant-based cloth until the 19th century, when cotton overtook flax as the most common plant for making rag-based paper. Flax is grown on the Canadian prairies for linseed oil, which is used as a drying oil in paints and varnishes and in products such as linoleum and printing inks. Linseed meal, the by-product of producing linseed oil from flax seeds, is used as livestock
fodder Fodder (), also called provender (), is any agriculture, agricultural foodstuff used specifically to feed domesticated livestock, such as cattle, domestic rabbit, rabbits, sheep, horses, chickens and pigs. "Fodder" refers particularly to food g ...
.Heuzé V., Tran G., Nozière P., Lessire M., Lebas F., 2017. Linseed meal. Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. Last updated on 16 February 2017, 16:31


Flax seeds

Flax seeds occur in two basic varieties/colors: brown or yellow (golden linseeds). Most types of these basic varieties have similar nutritional characteristics and equal numbers of short-chain omega-3 fatty acids. Yellow flax seeds, called solin ( trade name "
Linola Linola is the trademark name of solin, cultivated forms of flax (''Linum usitatissimum'') bred for producing linseed oil with a low alpha-linolenic acid content. Linola was developed in the early 1990s by the Commonwealth Scientific and Industrial R ...
"),CRS Report for Congress: Agriculture: A Glossary of Terms, Programs, and Laws, 2005 Edition – Order Code 97-905
have a similar oil profile to brown flax seeds and both are very high in omega-3s ( alpha-linolenic acid (ALA), specifically). Flax seeds produce a vegetable oil known as flax seed oil or
linseed oil Linseed oil, also known as flaxseed oil or flax oil (in its edible form), is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant (''Linum usitatissimum''). The oil is obtained by pressing, sometimes followed by ...
, which is one of the oldest commercial oils. It is an edible oil obtained by
expeller pressing Expeller pressing (also called oil pressing) is a mechanical method for extracting oil from raw materials. The raw materials are squeezed under high pressure in a single step. When used for the extraction of food oils, typical raw materials are ...
and sometimes followed by solvent extraction. Solvent-processed flax seed oil has been used for many centuries as a drying oil in painting and varnishing. Although brown flax seed varieties may be consumed as readily as the yellow ones, and have been for thousands of years, these varieties are more commonly used in paints, for fiber, and for cattle feed.


Culinary

A 100-gram portion of ground flax seed supplies about of food energy, 41 g of fat, 28 g of fiber, and 20 g of protein. Whole flax seeds are chemically stable, but ground flax seed meal, because of oxidation, may go rancid when left exposed to air at room temperature in as little as a week. Refrigeration and storage in sealed containers will keep ground flax seed meal for a longer period before it turns rancid. Under conditions similar to those found in commercial bakeries, trained sensory panelists could not detect differences between bread made with freshly ground flax seed and bread made with flax seed that had been milled four months earlier and stored at room temperature. If packed immediately without exposure to air and light, milled flax seed is stable against excessive oxidation when stored for nine months at room temperature, and under warehouse conditions, for 20 months at ambient temperatures. Three
phenolic Phenolic is an adjective and a substantive (noun) that may apply to : * Phenol (or carbolic acid), a colorless crystalline solid and aromatic compound * Phenols, a class of chemical compounds that include phenol * Phenolic content in wine * Phenol ...
glucoside A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. The name was o ...
s— secoisolariciresinol diglucoside, p-coumaric acid glucoside, and ferulic acid glucoside—are present in commercial breads containing flax seed.


Fodder

After crushing the seeds to extract linseed oil, the resultant linseed meal is a protein-rich feed for ruminants,
rabbit Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit speci ...
s, and fish. It is also often used as feed for swine and poultry, and has also been used in horse concentrate and dog food. The high omega-3 fatty acid (
ALA Ala, ALA, Alaa or Alae may refer to: Places * Ala, Hiiu County, Estonia, a village * Ala, Valga County, Estonia, a village * Ala, Alappuzha, Kerala, India, a village * Ala, Iran, a village in Semnan Province * Ala, Gotland, Sweden * Alad, Seydu ...
) content of linseed meal "softens" milk, eggs or meat, which means it causes a higher
unsaturated fat An unsaturated fat is a fat or fatty acid in which there is at least one double bond within the fatty acid chain. A fatty acid chain is monounsaturated if it contains one double bond, and polyunsaturated if it contains more than one double bond. ...
content and thus lowers its storage time. The high omega-3 content also has a further disadvantage, because this fatty acid
oxidise Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
s and goes rancid quickly, which shortens the storage time.
Linola Linola is the trademark name of solin, cultivated forms of flax (''Linum usitatissimum'') bred for producing linseed oil with a low alpha-linolenic acid content. Linola was developed in the early 1990s by the Commonwealth Scientific and Industrial R ...
was developed in Australia and introduced in the 1990s with less omega-3, specifically to serve as
fodder Fodder (), also called provender (), is any agriculture, agricultural foodstuff used specifically to feed domesticated livestock, such as cattle, domestic rabbit, rabbits, sheep, horses, chickens and pigs. "Fodder" refers particularly to food g ...
. Another disadvantage of the meal and seed is that it contains a vitamin B6 (
pyridoxine Pyridoxine, is a form of vitamin B6 found commonly in food and used as a dietary supplement. As a supplement it is used to treat and prevent pyridoxine deficiency, sideroblastic anaemia, pyridoxine-dependent epilepsy, certain metabolic disorde ...
) antagonist, and may require this vitamin be supplemented, especially in chickens, and furthermore linseeds contain 2–7% of mucilage (fibre), which may be beneficial in humans and cattle, but cannot be digested by non-ruminants and can be detrimental to young animals, unless possibly treated with enzymes. Linseed meal is added to
cattle feed There are different systems of feeding cattle in animal husbandry. For pastured animals, grass is usually the forage that composes the majority of their diet. Cattle reared in feedlots are fed hay supplemented with grain, soy and other ingredi ...
as a protein
supplement Supplement or Supplemental may refer to: Health and medicine * Bodybuilding supplement * Dietary supplement * Herbal supplement Media * Supplement (publishing), a publication that has a role secondary to that of another preceding or concurre ...
. It can only be added at low percentages due to the high fat content, which is unhealthy for ruminants. Compared to oilseed meal from crucifers it measures as having lower nutrient values, however, good results are obtained in cattle, perhaps due to the mucilage, which may aid in slowing digestion and thus allowing more time to absorb nutrients. One study found that feeding flax seeds may increase omega-3 content in beef, while another found no differences. It might also act as a substitute for tallow in increasing marbling. In the US, flax-based feed for ruminants is often somewhat more expensive than other feeds on a nutrient basis. Sheep feeding on low quality forage are able to eat a large amount of linseed meal, up to 40% in one test, with positive consequences. It has been fed as supplement to
water buffaloes The water buffalo (''Bubalus bubalis''), also called the domestic water buffalo or Asian water buffalo, is a large bovid originating in the Indian subcontinent and Southeast Asia. Today, it is also found in Europe, Australia, North America, So ...
in India, and provided a better diet than forage alone, but not as good as when substituted with soy meal. It is considered an inferior protein supplement for swine because of its fibre, the vitamin antagonist, the high omega-3 content and its low lysine content, and can only be used in small amounts in the feed. Although it may increase the omega-3 content in eggs and meat, it is also an inferior and potentially toxic feed for poultry, although it can be used in small amounts. The meal is an adequate and traditional source of protein for rabbits at 8–10%. Its use in fish feeds is limited. Raw, immature linseeds contain an amount of
cyanogenic Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of a ...
compounds and can be dangerous for monogastric animals such as horses or rabbits. Boiling removes the danger. This is not an issue in meal cake due to the processing temperature during oil extraction. Flax
straw Straw is an agricultural byproduct consisting of the dry stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has a number ...
left over from the harvesting of oilseed is not very nutritious; it is tough and indigestible, and is not recommended to use as ruminant fodder, although it may be used as bedding or baled as windbreaks.


Flax fibers

Flax fiber is extracted from the bast beneath the surface of the stem of the flax plant. Flax fiber is soft, lustrous, and flexible; bundles of fiber have the appearance of blonde hair, hence the description "flaxen" hair. It is stronger than cotton fiber, but less elastic. The use of flax fibers dates back tens of millennia;
linen Linen () is a textile made from the fibers of the flax plant. Linen is very strong, absorbent, and dries faster than cotton. Because of these properties, linen is comfortable to wear in hot weather and is valued for use in garments. It also ...
, a refined textile made from flax fibers, was worn widely by
Sumer Sumer () is the earliest known civilization in the historical region of southern Mesopotamia (south-central Iraq), emerging during the Chalcolithic and early Bronze Ages between the sixth and fifth millennium BC. It is one of the cradles of c ...
ian priests more than 4,000 years ago. Industrial-scale flax fiber processing existed in antiquity. A Bronze Age factory dedicated to flax processing was discovered in
Euonymeia Euonymeia ( el, Ευωνύμεια, ''Evonímia''), also known by its medieval name Trachones ( el, Τράχωνες), and by its modern colloquial Ano Kalamaki ( el, Άνω Καλαμάκι, Upper Kalamaki), is a historic settlement in Athens a ...
, Greece. The best grades are used for fabrics such as damasks, lace, and
sheeting A bed sheet is a rectangular piece of cloth used either singly or in a pair as bedding, which is larger in length and width than a mattress, and which is placed immediately above a mattress or bed, but below blankets and other bedding (such as ...
. Coarser grades are used for the manufacturing of twine and rope, and historically, for
canvas Canvas is an extremely durable plain-woven fabric used for making sails, tents, marquees, backpacks, shelters, as a support for oil painting and for other items for which sturdiness is required, as well as in such fashion objects as handbags ...
and webbing equipment. Flax fiber is a raw material used in the high-quality paper industry for the use of printed banknotes, laboratory paper (
blotting A blot, in molecular biology and genetics, is a method of transferring proteins, DNA or RNA onto a carrier (for example, a nitrocellulose, polyvinylidene fluoride or nylon membrane). In many instances, this is done after a gel electrophoresis, t ...
and filter), rolling paper for
cigarette A cigarette is a narrow cylinder containing a combustible material, typically tobacco, that is rolled into thin paper for smoking. The cigarette is ignited at one end, causing it to smolder; the resulting smoke is orally inhaled via the opp ...
s, and tea bags.
Flax mill Flax mills are mills which process flax. The earliest mills were developed for spinning yarn for the linen industry. John Kendrew (an optician) and Thomas Porthouse (a clockmaker), both of Darlington developed the process from Richard Arkwrigh ...
s for spinning flaxen yarn were invented by John Kendrew and
Thomas Porthouse Thomas may refer to: People * List of people with given name Thomas * Thomas (name) * Thomas (surname) * Saint Thomas (disambiguation) * Thomas Aquinas (1225–1274) Italian Dominican friar, philosopher, and Doctor of the Church * Thomas the Ap ...
of
Darlington Darlington is a market town in the Borough of Darlington, County Durham, England. The River Skerne flows through the town; it is a tributary of the River Tees. The Tees itself flows south of the town. In the 19th century, Darlington underwen ...
, England, in 1787. New methods of processing flax have led to renewed interest in the use of flax as an industrial fiber.


Nutrition

Flax seeds are 7% water, 18% protein, 29% carbohydrates, and 42% fat (table). In as a reference amount, flax seeds provide 534
kilocalorie The calorie is a unit of energy. For historical reasons, two main definitions of "calorie" are in wide use. The large calorie, food calorie, or kilogram calorie was originally defined as the amount of heat needed to raise the temperature of on ...
s and contain high levels (20% or more of the Daily Value, DV) of protein,
dietary fiber Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by the ...
, several B vitamins, and dietary minerals. Flax seeds are especially rich in thiamine, magnesium, and phosphorus (DVs above 90%) (table). As a percentage of total fat, flax seeds contain 54% omega-3 fatty acids (mostly
ALA Ala, ALA, Alaa or Alae may refer to: Places * Ala, Hiiu County, Estonia, a village * Ala, Valga County, Estonia, a village * Ala, Alappuzha, Kerala, India, a village * Ala, Iran, a village in Semnan Province * Ala, Gotland, Sweden * Alad, Seydu ...
), 18%
omega-9 fatty acids Omega-9 fatty acids (ω−9 fatty acids or ''n''−9 fatty acids) are a family of unsaturated fatty acids which have in common a final carbon–carbon double bond in the omega−9 position; that is, the ninth bond from the methyl end of the fa ...
( oleic acid), and 6% omega-6 fatty acids ( linoleic acid); the seeds contain 9%
saturated fat A saturated fat is a type of fat in which the fatty acid chains have all single bonds. A fat known as a glyceride is made of two kinds of smaller molecules: a short glycerol backbone and fatty acids that each contain a long linear or branched c ...
, including 5% as palmitic acid. Flax seed oil contains 53% 18:3 omega-3 fatty acids (mostly ALA) and 13% 18:2 omega-6 fatty acids.


Health research

A meta-analysis showed that consumption of more than 30 g of flax-seed daily for more than 12 weeks reduced body weight,
body mass index Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is expressed in units of kg/m2, resulting from mass in kilograms and he ...
(BMI), and waist circumference for persons with a BMI greater than 27. Another meta-analysis showed that consumption of flax seeds for more than 12 weeks produced small reductions in systolic blood pressure and
diastolic blood pressure Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" r ...
. A third showed that consuming flax seed or its derivatives may reduce total and
LDL-cholesterol Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons (aka ULDL by the overall densit ...
in the blood, with greater benefits in women and people with high cholesterol. A fourth showed a small reduction in c-reactive protein (a marker of inflammation) only in persons with a body mass index greater than 30.


Linseed oil


Toxicity

Flax seed and its oil are generally recognized as safe for human consumption. Like many common foods, flax contains small amounts of cyanogenic glycoside, which is nontoxic when consumed in typical amounts, but may be toxic when consumed in large quantities as with
staple food A staple food, food staple, or simply a staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for a given person or group of people, supplying a large fraction of energy needs and ...
s such as cassava. Typical concentrations (for example, 0.48% in a sample of defatted dehusked flax seed meal) can be removed by special processing.


Cultivation

The soils most suitable for flax, besides the alluvial kind, are deep
loam Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–sil ...
s containing a large proportion of
organic matter Organic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have c ...
. Flax is often found growing just above the waterline in cranberry bogs. Heavy clays are unsuitable, as are soils of a
gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is classifi ...
ly or dry sandy nature. Farming flax requires few fertilizers or
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
s. Within eight weeks of sowing, the plant can reach in height, reaching within 50 days.


Diseases


Production

In 2020, world production of flax (linseed) was 3.4 million tonnes, led by Kazakhstan with 31% of the total. Other major producers were Russia, Canada, and
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
(table).


Harvesting


Maturation

Flax is harvested for fiber production after about 100 days, or a month after the plants flower and two weeks after the seed capsules form. The bases of the plants begin to turn yellow. If the plants are still green, the seed will not be useful, and the fiber will be underdeveloped. The fiber degrades once the plants turn brown. Flax grown for seed is allowed to mature until the seed capsules are yellow and just starting to split; it is then harvested in various ways. A
combine harvester The modern combine harvester, or simply combine, is a versatile machine designed to efficiently harvest a variety of grain crops. The name derives from its combining four separate harvesting operations—reaping, threshing, gathering, and winnow ...
may either cut only the heads of the plants, or the whole plant. These are then dried to extract the seed. The amount of weeds in the straw affects its marketability, and this, coupled with market prices, determines whether the farmer chooses to harvest the flax straw. If the flax straw is not harvested, typically, it is burned, since the stalks are quite tough and decompose slowly (''i.e.'', not in a single season). Formed into windrows from the harvesting process, the straw often clogs up tillage and planting equipment. Flax straw that is not of sufficient quality for fiber uses can be baled to build shelters for farm animals, or sold as biofuel, or removed from the field in the spring. Two ways are used to harvest flax fiber, one involving mechanized equipment (combines), and a second method, more manual and targeting maximum fiber length.


Harvesting for fiber


Mechanical

Flax for fiber production is usually harvested by a specialized flax harvester. Usually built on the same machine base as a combine, but instead of the cutting head it has a flax puller. The flax plant turned over and is gripped by rubber belts roughly 20–25 cm (8–10 inches) above ground, to avoid getting grasses and weeds in the flax. The rubber belts then pull the whole plant out of the ground with the roots so the whole length of the plant fiber can be used. The plants then pass over the machine and is placed on the field crosswise to the harvesters direction of travel. The plants are left in the field for field retting. The mature plant can also be cut with mowing equipment, similar to hay harvesting, and raked into windrows. When dried sufficiently, a combine then harvests the seeds similar to wheat or oat harvesting.


Manual

The plant is pulled up with the roots (not cut), so as to increase the fiber length. After this, the flax is allowed to dry, the seeds are removed, and it is then retted. Dependent upon climatic conditions, characteristics of the sown flax and fields, the flax remains on the ground between two weeks and two months for retting. As a result of alternating rain and the sun, an enzymatic action degrades the pectins which bind fibers to the straw. The farmers turn over the straw during retting to evenly rett the stalks. When the straw is retted and sufficiently dry, it is rolled up. It is then stored by farmers before extracting the fibers.


Processing

Threshing is the process of removing the seeds from the rest of the plant. Separating the usable flax fibers from other components requires pulling the stems through a hackle and/or beating the plants to break them. Flax processing is divided into two parts: the first part is generally done by the farmer, to bring the flax fiber into a fit state for general or common purposes. This can be performed by three machines: one for threshing out the seed, one for breaking and separating the straw (stem) from the fiber, and one for further separating the broken straw and matter from the fiber. The second part of the process brings the flax into a state for the very finest purposes, such as lace, cambric, damask, and very fine
linen Linen () is a textile made from the fibers of the flax plant. Linen is very strong, absorbent, and dries faster than cotton. Because of these properties, linen is comfortable to wear in hot weather and is valued for use in garments. It also ...
. This second part is performed by a refining machine.


Preparation for spinning

Before the flax fibers can be spun into linen, they must be separated from the rest of the stalk. The first step in this process is retting, which is the process of rotting away the inner stalk, leaving the outer parts intact. At this point, straw, or coarse outer stem ( cortex and
epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rele ...
), is still remaining. To remove this, the flax is "broken", the straw is broken up into small, short bits, while the actual fiber is left unharmed. Scutching scrapes the outer straw from the fiber. The stems are then pulled through "hackles", which act like combs to remove the straw and some shorter fibers out of the long fiber.


Retting flax

Several methods are used for retting flax. It can be retted in a pond, stream, field, or tank. When the retting is complete, the bundles of flax feel soft and slimy, and quite a few fibers are standing out from the stalks. When wrapped around a finger, the inner woody part springs away from the fibers. Pond retting is the fastest. It consists of placing the flax in a pool of water which will not evaporate. It generally takes place in a shallow pool which will warm up dramatically in the sun; the process may take from a few days to a few weeks. Pond-retted flax is traditionally considered of lower quality, possibly because the product can become dirty, and is easily over-retted, damaging the fiber. This form of retting also produces quite an odor. Stream retting is similar to pool retting, but the flax is submerged in bundles in a stream or river. This generally takes two or three weeks longer than pond retting, but the end product is less likely to be dirty, does not smell as bad, and because the water is cooler, is less likely to be over-retted. Both pond and stream retting were traditionally used less because they pollute the waters used for the process. In field retting, the flax is laid out in a large field, and dew is allowed to collect on it. This process normally takes a month or more, but is generally considered to provide the highest quality flax fibers, and it produces the least pollution. Retting can also be done in a plastic trash can or any type of water-tight container of wood, concrete, earthenware, or plastic. Metal containers will not work, as an acid is produced when retting, and it would
corrode Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...
the metal. If the water temperature is kept at , the retting process under these conditions takes 4 or 5 days. If the water is any colder, it takes longer. Scum collects at the top, and an odor is given off the same as in pond retting. 'Enzymatic' retting of flax has been researched as a technique to engineer fibers with specific properties.


Dressing the flax

File:Harfleur - Compagnons duellistes - teillage du lin.jpg, Breaking flax File:Harfleur - Compagnons duellistes - battage du lin.jpg, Scutching flax File:Harfleur - Compagnons duellistes - peignage du lin.jpg, Heckling flax File:Flax fibers.JPG, Flax fiber in different forms, before and after processing Dressing the flax is the process of removing the straw from the fibers. Dressing consists of three steps: breaking, scutching, and heckling. The breaking breaks up the straw. Some of the straw is scraped from the fibers in the scutching process, and finally, the fiber is pulled through heckles to remove the last bits of straw. Breaking breaks up the straw into short segments. Scutching removes some of the
straw Straw is an agricultural byproduct consisting of the dry stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has a number ...
from the fiber. Heckling is pulling the fiber through various sizes of
heckling comb Heckling (or "hackling") is the last of three steps in dressing flax, or preparing the fibers to be spun. It splits and straightens the flax fibers, as well as removes the fibrous core and impurities."Heckle." ''The Oxford English Dictionary''. 2n ...
s or heckles. A heckle is a bed of "nails"—sharp, long-tapered, tempered, polished steel pins driven into wooden blocks at regular spacing.


Genetically modified flax contamination

In September 2009, Canadian flax exports reportedly had been contaminated by a deregistered genetically modified cultivar called 'Triffid' that had food and feed safety approval in Canada and the U.S. Canadian growers and the Flax Council of Canada raised concerns about the marketability of this cultivar in Europe where a zero tolerance policy exists regarding unapproved
genetically modified organism A genetically modified organism (GMO) is any organism whose genetic material has been altered using genetic engineering techniques. The exact definition of a genetically modified organism and what constitutes genetic engineering varies, with ...
s. Consequently, Triffid was deregistered in 2010 and never grown commercially in Canada or the U.S. Triffid stores were destroyed, but future exports and further tests at the University of Saskatchewan proved that Triffid persisted in at least two Canadian flax varieties, possibly affecting future crops. Canadian flax seed cultivars were reconstituted with Triffid-free seed used to plant the 2014 crop. Laboratories are certified to test for the presence of Triffid at a level of one seed in 10,000.


Symbolic images

Flax is an emblem of Northern Ireland and displayed by the
Northern Ireland Assembly sco-ulster, Norlin Airlan Assemblie , legislature = 7th Northern Ireland Assembly, Seventh Assembly , coa_pic = File:NI_Assembly.svg , coa_res = 250px , house_type = Unicameralism, Unicameral , hou ...
. In a coronet, it appeared on the reverse of the British one-pound coin to represent Northern Ireland on coins minted in 1986, 1991, and 2014. Flax also represents Northern Ireland on the badge of the
Supreme Court of the United Kingdom The Supreme Court of the United Kingdom (initialism: UKSC or the acronym: SCOTUK) is the final court of appeal in the United Kingdom for all civil cases, and for criminal cases originating in England, Wales and Northern Ireland. As the Unite ...
and on various logos associated with it. Common flax is the national flower of Belarus. In early versions of the Sleeping Beauty tale, such as "
Sun, Moon, and Talia ''Sun, Moon, and Talia'' () is an Italian literary fairy tale written by Giambattista Basile in his 1634 work, the ''Pentamerone''. Charles Perrault retold this fairy tale in 1697 as '' The Sleeping Beauty'', as did the Brothers Grimm in 1812 as ' ...
" by Giambattista Basile, the princess pricks her finger, not on a spindle, but on a sliver of flax, which later is sucked out by her children conceived as she sleeps.


See also

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References

{{Authority control Linum Fiber plants Crops originating from Asia Flora of Western Asia Crops Biodegradable materials Demulcents Painting materials Plants described in 1753 Articles containing video clips Founder crops