Linseed, flaxseed [German version]

Table of contents

Product information
  Container transport
  Cargo securing

Risk factors and loss prevention:
Temperature Odor
Humidity/Moisture Contamination
Ventilation Mechanical influences
Biotic activity Toxicity / Hazards to health
Gases Shrinkage/Shortage
Self-heating / Spontaneous combustion Insect infestation / Diseases

Product information

Product name

German Leinsaat, Flachssaat
English Linseed, flax seed
French Graine de Lin
Spanish Linaza
Scientific Linum usitatissimum
CN/HS number * 1204 00 ff.

(* EU Combined Nomenclature/Harmonized System)

Product description

Linseed or flaxseed is the seed from the flax plant (Linum usitatissimum), which is a member of the Linaceae family and is a source of both oil and fiber. The seed is of a flattened, elongated oval shape with a brown-yellowish color and a glossy surface. The plant is native to West Asia and the Mediterranean.

The dimensions of the seed are approx.:

Dimensions Fiber flax Oil flax
Length [mm] 3.0 – 4.9 4.8 – 6.4
Width [mm] 1.8 – 2.6 2.5 – 3.4
Thickness [mm] 0.5 – 1.0 0.9 – 1.6

The spherical fruit capsules contain two smooth, brownish seeds in each of 5 compartments.

Oil content:

30 – 47.8% [1]
37 – 40% [11]

Quality / Duration of storage

Quality degradation occurs in particular with excessively moist and excessively hot product and may be recognized from internal discoloration of the seed and a musty odor.

At a water content of 9 – 10.5%, linseed has a storage life of more than 12 months.

The most favorable time for shipment is shortly after harvest.

Intended use

Linseed is used for oil extraction (linseed oil is used as a raw material in the paints and coatings industry), as seed and as bird and livestock feed.


(Click on the Figures to enlarge them.)

Photo, linseed

Figure 1
Photo, linseed

Figure 2
Drawing, flax

Figure 3

Countries of origin

This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.

Europe Black Sea region, Baltic states
Asia Black Sea region, Baltic states
America USA, La Plata basin

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Linseed has the characteristic of germinating or sprouting easily (the easiest of all oilseeds) and is thus mainly packaged as break-bulk cargo in, among other things, flat jute fabric bags (65 kg). Transport as a bulk cargo is very rare due to the stated characteristic.

Marking of packages
Mark07.gif (2224 bytes)

Keep dry
Mark02.gif (2816 bytes)

Use no hooks
Mark04.gif (3269 bytes)

Keep away
from heat
(solar radiation)

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Symbol, general cargo

General cargo

Bulk cargo (rare)

Means of transport

Ship, truck, railroad

Container transport

Ventilated containers (coffee containers), if the lower limits set for the water content of goods, packaging and container flooring and the oil content of the goods are complied with.

Cargo handling

In damp weather (rain, snow), the cargo must be protected from moisture, since it may lead to mold, spoilage and self-heating as a result of increased respiratory activity. 

Hooks must not be used in handling bagged goods as they subject the cargo to point loads, so damaging the bags. Due to their shape, plate or bag hooks apply an area load and are thus more suitable for handling bags.

Stowage factor

1.70 m³/t (jute bags, 65 kg) [1]
1.59 – 1.70 m³/t (bags) [11]

Stowage space requirements

Cool, dry, good ventilation. In order to avoid rancidity due to contact with metal components of the ship, the product should be covered with wooden dunnage, mats or jute coverings.


Fiber rope, thin fiber nets

Cargo securing

In the case of maritime transport of bulk cargo, the IMO (International Maritime Organization) „Code of Safe Practice for Solid Bulk Cargoes“ must be complied with.

Of all oilseeds, linseed is the cargo which shifts most readily. Appropriate securing measures must therefore be taken when transporting the product as a bulk cargo (e.g. installation of additional bulkheads, bins and feeders).

Bagged cargo must be stowed and secured in the means of transport in such a manner that it cannot slip or shift during transport. If loss of volume and degradation of quality are to be avoided, the packages must not be damaged by other articles or items of cargo.

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Risk factors and loss prevention

RF Temperature

Linseed requires particular temperature, humidity/moisture and ventilation conditions (SC VII) (storage climate conditions).

Favorable travel temperature range: 5 – 25°C [1]

Temperatures > 30°C should not prevail for an extended period, as such temperatures promote respiration of the cargo and may cause self-heating. The cargo should be stowed away from sources of heat.

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RF Humidity/Moisture

Linseed requires particular temperature, humidity/moisture and ventilation conditions (SC VII) (storage climate conditions).

Designation Humidity/water content Source
Relative humidity 70% [1]
Water content 9 – 10.5% [1]
Maximum equilibrium moisture content 65% [1]

Linseed must be protected from all forms of moisture (seawater, rain and condensation water), since moisture promotes hydrolytic/enzymatic fat cleavage, which then results in self-heating due to increased respiration. 

The sorption isotherm for linseed shows that, at a water content of 9 – 10.5%, it is at equilibrium with a relative humidity of 79 – 75%, i.e. the mold growth threshold is already reached.

Sorption isotherm

Figure 4

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RF Ventilation

Linseed requires particular temperature, humidity/moisture and ventilation conditions (SC VII) (storage climate conditions).

Recommended ventilation conditions: air exchange rate at least 10 changes/hour (airing)

It is advisable to stow so as to leave trenches, so that, where necessary, water vapor and heat may be removed by suitable ventilation measures.

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RF Biotic activity

Linseed displays 2nd order biotic activity.

It is a living organ in which respiration processes predominate, because its supply of new nutrients has been cut off by separation from the parent plant.

The fat decomposition which takes place during the course of hydrolytic/enzymatic fat cleavage increases the risk of the cargo undergoing self-heating, possibly ultimately resulting in a cargo fire.

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RF Gases

In linseed, metabolic processes continue even after harvesting. The linseed absorbs oxygen and excretes carbon dioxide (CO2).

Respiration may cause life-threatening CO2 concentrations (TLV: 0.49 vol.%) or O2 shortages in the hold/container. Therefore, before anybody enters the hold, it must be ventilated and a gas measurement carried out.

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RF Self-heating / Spontaneous combustion

Oil content:

30 – 47.8% [1]
37 – 40% [11]

Linseed’s elevated oil content promotes its tendency towards self-heating.

Because of its tendency to self-heating/spontaneous combustion, linseed may behave like substances from Class 4.2 of the IMDG Code. See also IMO Code of Safe Practice for Solid Bulk Cargoes.

Fat decomposition in linseed leads to the risk of self-heating and, finally, to a cargo fire.

Fat decomposition may proceed as follows:

by hydrolytic/enzymatic fat cleavage or
by oxidative fat cleavage

Hydrolytic/enzymatic fat cleavage:

If the critical water content of linseed is exceeded, this promotes hydrolytic/enzymatic fat cleavage. Fat-cleaving enzymes are activated by the elevated water content. The additional action of light and heat may accelerate this process. Free fatty acids sometimes have an unpleasant odor and taste. In the event of extended storage or improper cargo care, these cause the cargo to become rancid.

The free fatty acids formed are consumed by respiration processes in the linseed to form carbon dioxide and water, a process which is associated with considerable evolution of heat.

Self-heating of linseed is an extremely vigorous process, as the consumption of fatty acids by respiration processes is associated with a considerably greater evolution of heat than is the case with the respiration equation for carbohydrates. Here too, as with cereals, the spoilage process proceeds in a type of chain reaction, because heat and water are formed by the fatty acids consumed by respiration, which in turn contribute to an intensification of the process.

The self-heating of linseed requires only a small seat of moisture, so that within just a few hours heating may occur at moist points for which weeks or months would be required in goods dry on shipment.

Fresh linseed with a high moisture content tends rapidly towards self-heating and may also ignite. Self-heating of linseed leads not only to a reduction in the utility value of this product (rancid odor and taste) but also has a qualitative and quantitative effect on oil yield. The color and bleachability of the oils are also negatively affected. The oil obtained complicates refining of the crude oils in subsequent processing, because a higher free fatty acid content makes decolorization substantially more difficult.

Hydrolytic/enzymatic fat cleavage and respiration may be limited by low temperatures; however, this may only be affected to a limited degree during transport. It is therefore important to ensure storage stability by complying with the limit values for the water content of the goods.

Oxidative fat cleavage:

Food components frequently react with atmospheric oxygen in spoilage reactions. Atmospheric oxygen may enter into an addition reaction with unsaturated fatty acids through the simultaneous assistance of light, heat and certain fat companion substances, and possibly also traces of heavy metals. It is therefore absolutely essential to store linseed in the dark and to protect it from oxygen and metal parts, since otherwise it becomes brown-colored and develops a rancid odor and taste.

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RF Odor

Active behavior Linseed has a slight, unpleasant odor, which is of a highly specific nature.
Passive behavior Linseed should be stowed away from strong-smelling goods, such as turpentine, onions, fruit.

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RF Contamination

Active behavior The high oil content of the goods frequently causes dark fat stains to appear on the bags, which must therefore be kept from coming into contact with goods sensitive to contamination, such as baled goods, tea chests, marble etc..

Linseed in bags must not be stowed together with fibers or fibrous materials, either, since oil-impregnated fibers accelerate self-heating processes.

Linseed originating from the Near East in particular often contains a large proportion of fine sand.

Linseed flows very easily, passing through jute bags, so resulting in considerable contamination and sweepings.
Passive behavior Linseed is sensitive to dirt, fats and oils. The holds or containers must accordingly be clean and in a thoroughly hygienic condition before loading.

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RF Mechanical influences

Point loads applied for example by hooks may result in damage (tears) to the bags and thus to losses of volume. Plate or bag hooks, which, due to their shape, distribute the load and reduce the risk of damage, should thus be used.

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RF Toxicity / Hazards to health

Respiration may cause life-threatening CO2 concentrations (TLV: 0.49 vol.%) or O2 shortages in the hold/container. Therefore, before anybody enters the hold, it must be ventilated and a gas measurement carried out.

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RF Shrinkage/Shortage

Torn bags may lead to slight losses in volume.

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RF Insect infestation / Diseases

Typical pests of oil-bearing seeds/fruits are, for example, merchant grain beetles, peanut weevils, sawtoothed grain beetles, flour beetles, meal moths, dried fruit moths and mites, which may cause depreciation and weight losses.

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