Difference between revisions of "Barley"
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Up to a water content of 15%, surface ventilation is recommended, such to dissipate CO<sub>2</sub>, heat and moisture. Concurrently, care should be taken to ensure that the surfaces are not cooled too much, to prevent the formation of damp boundary layers beneath the cargo surface. | Up to a water content of 15%, surface ventilation is recommended, such to dissipate CO<sub>2</sub>, heat and moisture. Concurrently, care should be taken to ensure that the surfaces are not cooled too much, to prevent the formation of damp boundary layers beneath the cargo surface. | ||
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| − | Barley releases water vapor constantly, which needs to be dissipated by ventilation. However, caution is advisable on voyages from hot to cold regions (e.g. South America to N. Europe. Barley which is not dry for shipment has a particular tendency to self-heating and the flow of heat from the cargo counteracts external cooling, so resulting in the formation of significant temperature gradients in the superficial layers of the cargo. Concurrently, water vapor flows from the inside of the cargo to the surface. In the case of simultaneous cooling of the surface by ventilation, the relative humidity increases in the superficial layers of the cargo. If dry fresh air is used for ventilation, a dry surface layer several centimeters thick is obtained, which creates the impression that the cargo is free of all defects. Beneath this is then a damp intermediate layer of adverse cereal which is starting to decompose, coagulate and swollen. | + | Barley releases water vapor constantly, which needs to be dissipated by ventilation. However, caution is advisable on voyages from hot to cold regions (e.g. South America to N. Europe). Barley which is not dry for shipment has a particular tendency to self-heating and the flow of heat from the cargo counteracts external cooling, so resulting in the formation of significant temperature gradients in the superficial layers of the cargo. Concurrently, water vapor flows from the inside of the cargo to the surface. In the case of simultaneous cooling of the surface by ventilation, the relative humidity increases in the superficial layers of the cargo. If dry fresh air is used for ventilation, a dry surface layer several centimeters thick is obtained, which creates the impression that the cargo is free of all defects. Beneath this is then a damp intermediate layer of adverse cereal which is starting to decompose, coagulate and swollen. |
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In order to avoid cargo damage caused by such moist intermediate layers, the fresh air supply must be restricted when there is an excessive temperature differential between the cargo and the external temperature. | In order to avoid cargo damage caused by such moist intermediate layers, the fresh air supply must be restricted when there is an excessive temperature differential between the cargo and the external temperature. | ||
Revision as of 12:00, 1 June 2012
| Infobox on Barley | |
|---|---|
| Example of Barley |  |
| Facts | |
| Origin | This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive
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| Stowage factor (in m3/t) |
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| Angle of repose | Approx. 25° (average value) |
| Humidity / moisture |
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| Oil content | The oil content of barley is approx. 2%. |
| Ventilation | Recommended ventilation conditions: surface ventilation (see text) |
| Risk factors | risk factors = *CO2Gases* Temperature; favorable travel temperature range: no lower limit - 20°C. Molds reach optimum activity at temperatures of between 20 and 30°C. In addition, at temperatures > 25°C, metabolic processes increase, leading to increased CO2 production and self-heating of the barley
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Barley
Description
Barley is a type of cereal belonging to the grass family, the term "cereals" covering the grain fruits of cultivated grasses (spikes or ears in the case of wheat, rye, barley and corn; panicles in the case of oats and rice).
Barley is not only grown in the summer, but also in the winter.
The structure and chemical composition of the grain vary little between the different types of cereal.
It consists of three components:
its cracked husk, the endosperm, which constitutes the main component of the grain and the embryo.
After harvesting, barley usually undergoes further post-ripening. As the surface of the cereal then becomes damp because of the elevated water content, this is described as "sweating. In this state, the cereal is highly susceptible to mold and should not as yet be shipped. However, if the water content of the cereal is relatively low (approx. 13 - 14%), proper storage allows the sweat moisture to be absorbed by the air without the risk of mold growth. This sweating process proceeds for a period of approximately 1 - 2 months.
Prior to loading, checks should be carried out and a certificate provided in relation to the moisture content, the absence of odor and contamination and the absence of pests.
Excessively damp and incompletely ripened grain may be liable to self-heating, elevated respiratory activity, mold growth and fermentation during transport.
The storage potential of barley which is "dry for shipment" may be up to 12 months or longer provided that the appropriate temperature, humidity/moisture and ventilation conditions are complied with.
Applications
It serves as a major animal fodder, a source of fermentable material for beer and certain distilled beverages, and as a component of various health foods. It is used in soups and stews, and in barley bread of various cultures. Barley grains are commonly made into malt in a traditional and ancient method of preparation.
Shipping/storage
Barley is chiefly transported as bulk cargo and only sometimes in bags (seed).
Stowage space requirements
Cool, dry, good ventilation.
Humidity/Moisture
Problems of moisture may be avoided by adequate pre-drying of the barley. This is the best way of reducing the activity (respiration) of the grain and removing the nutrient medium for mold growth and spoilage processes. The necessary level of dryness is approx. 11 - 14% water content, which is at equilibrium with relative humidity of up to 70% at 25°C. The mold growth threshold is reached at a water content of 15% (75% relative humidity). In cold transport regions, a relative humidity of 70% would be at equilibrium and the barley would not sustain any damage even at that level. At 16 - 17% water content, the sorption isotherm climbs sharply, implicating that equilibrium moisture contents of > 80% very rapidly produce an excessively damp atmosphere.
Individual clusters of damp product could initiate considerable damage to the cargo. The barley in such clusters has a tendency to self-heating. Damp (sweating) barley then appears in the boundary layers, so allowing the process to develop further. Such clusters may form, for example, in too freshly harvested product or where damp goods have been loaded.
Prior to loading, the loading moisture content should be checked by an independent inspector and a certificate provided.
Ventilation
Recommended ventilation conditions: surface ventilation. Ventilation of cereals depends on water content: goods with a water content of < 13% and equilibrium moisture contents of < 70% do not need to be ventilated.
Up to a water content of 15%, surface ventilation is recommended, such to dissipate CO2, heat and moisture. Concurrently, care should be taken to ensure that the surfaces are not cooled too much, to prevent the formation of damp boundary layers beneath the cargo surface.
Barley releases water vapor constantly, which needs to be dissipated by ventilation. However, caution is advisable on voyages from hot to cold regions (e.g. South America to N. Europe). Barley which is not dry for shipment has a particular tendency to self-heating and the flow of heat from the cargo counteracts external cooling, so resulting in the formation of significant temperature gradients in the superficial layers of the cargo. Concurrently, water vapor flows from the inside of the cargo to the surface. In the case of simultaneous cooling of the surface by ventilation, the relative humidity increases in the superficial layers of the cargo. If dry fresh air is used for ventilation, a dry surface layer several centimeters thick is obtained, which creates the impression that the cargo is free of all defects. Beneath this is then a damp intermediate layer of adverse cereal which is starting to decompose, coagulate and swollen.
In order to avoid cargo damage caused by such moist intermediate layers, the fresh air supply must be restricted when there is an excessive temperature differential between the cargo and the external temperature.
It is impossible to ensure proper airing throughout a bulk cargo of cereals. Even when ventilation is carried out, the relative humidity of the immobile air between the individual cereal grains is determined by the product's water content. For this reason, drying-out caused by ventilation is generally only superficial.
As a result, cereal loaded in an excessively moist state cannot be dried and protected from spoilage by a ship's ventilation installation.
Note: (Source including Transport Information Service of the GDV)