|Infobox on Soybeans
|Example of Soybeans
|This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.
|Stowage factor (in m3/t)
|Angle of repose
|Humidity / moisture
|13 - 24%
|Recommended ventilation conditions: air exchange rate: 10 - 20 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.
|Soybeans are sensitive to contamination, moisture damage and insect infestation. 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.
Soya Beans (Soybeans) are one of the major cargoes shipped around the world. They consist chemically of about 20% oil, 45% protein, 5%-7% fibre together with various carbohydrates. Soybeans occur in various sizes, and in many hull or seed coat colors, including black, brown, blue, yellow, green and mottled. The hull of the mature bean is hard, water resistant, and protects the cotyledon and hypocotyl (or "germ") from damage. If the seed coat is cracked, the seed will not germinate. The scar, visible on the seed coat, is called the hilum (colors include black, brown, buff, gray and yellow) and at one end of the hilum is the micropyle, or small opening in the seed coat which can allow the absorption of water for sprouting.
Soya beans are used for the manufacture of two principal products: soybean oil and soybean meal, the latter being the product remaining after the oil has been removed, invariably by the solvent extraction process. They also form the bases for the production of soy protein, soy coagulates (e.g. tofu), soy sauces.
Soya beans are, of course, a perishable commodity and one cannot expect to store them indefinitely. The concept of “safe storage” is probably incorrect since there is no particular set of conditions under which bulk soya beans cannot be damaged. However, the two crucial aspects are heat and moisture. The period of safe storage (before noticeable deterioration occurs) depends largely on the initial moisture content, the temperature of the beans at loading and the subsequent storage conditions; higher temperatures and moisture content increase the rate of deterioration.
Fully matured soybeans may be kept for a virtually unlimited time after drying. With a water content of 8%, soybeans have a very good storage life and are thus also well suited to being transported for relatively long periods and in bulk. Shipping is possible all year round, but should be as soon as possible after harvest, in order to avoid transporting excessively old goods. The year of harvest should therefore be ascertained before loading is begun. Soybeans are generally transported as bulk cargo but occasionally also as break-bulk cargo in bags of woven natural materials (e.g. jute) or woven plastic bags. Transport in ventilated containers (coffee containers), if the water content of the goods is < 8% and the lower limits set for the water content of packaging and container flooring and the oil content of the goods are complied with.
The effect of moisture content on a shipment of soya beans can be summarized as follows:
1. It is a natural characteristic of soya beans when shipped in bulk that if the moisture content of the bulk exceeds 14 per cent, micro-biological action will inevitably cause the soya beans to deteriorate during the course of a normal voyage from Indonesia to Northern Europe to an extent which will considerably reduce their value on arrival.
2. With a moisture content of between 12 and 14 per cent (below 12 per cent no micro-biological action occurs), there is a risk that deterioration from micro-biological action can occur during the course of such a voyage. The range of moisture content between 12 and 14 per cent is referred to as the "grey area".
Soya beans are in equilibrium with surrounding air at 25°C at a moisture content of 13% to 13.3% at 65% relative humidity.
This means that at 25°C, soya beans with a moisture content higher than 13.3% will have an increased risk of being damaged during long term storage. Equally, soya beans with a moisture content lower than 13.3% at 25°C will have a decreased risk of being damaged; below 13% the risk is minimal. At temperatures above 25°C, the moisture content must be lower than 13% for safe storage, while at temperatures below 25°C it can be higher.
These values must be used with caution since there are differences in the values obtained depending on the variety of soya beans tested, the conditions under which they were grown and their post-harvest history. Thus, the value of 13% to 13.3% moisture content at 25°C represents a practical compromise in terms of stating a critical limit for the safe storage of soya beans.
However, each cargo must be viewed individually. Age, moisture content, oil content, FFA (Free Fatty Acid) content, temperature, storage conditions and transport history are all important when considering a particular cargo.
The standard contract specifications for South American soya beans often give a maximum value for moisture content of 14%. There may also be local by-laws which can provide that below a certain moisture content, the cargo is deemed - on the basis of the local rules - to be fit for shipment.
These laws / rules generally do not, however, take into account the other factors that may impact on the “shelf life” / “transport time limit” of the cargo. This can, and has in the past, led to difficulties when Shippers have insisted a particular parcel is fit for shipment on the basis of a certain “alleged” moisture content.
It has also been noted that the moisture level being claimed for a particular cargo may not always be accurate, with individual parcels being found (on testing) to vary significantly. A “bad” parcel of a few hundred tons of beans with a high risk of deterioration can affect the rest of the cargo in a particular cargo hold. At worst, it can lead to a rejection of the entire hold load at the discharge port with a consequently significant claim following.
The average passage from Brazil to PRC takes approximately 32 days; as such, practical consideration can and should be given as to what measures the ship can take to help protect the cargo and engage in good loss prevention.
Soya beans are a living cargo so there will be a natural tendency for cargoes composed of them to heat up because of biological activity.
Most natural organic products, including soya beans, loaded in equatorial and tropical climates tend to throw off warm, moist air during a voyage. While the vessel remains in equatorial waters, there is little risk of ship’s sweat occurring, as the ship remains at a temperature close to or above the dew point*. However, when the vessel enters colder waters and the structure cools, there can then be a significant risk of ship’s sweat occurring. Ship’s sweat can be prevented by ventilating the cargo spaces.
Ventilation can remove the warm moist air thrown off by the cargo with drier outside air, before sweat can form on the inside of the hold. However, the dew point of the outside air must be below the dew point of the air in the hold. If the temperature in the hold is lower than the dew point of the ventilating air, moisture in the outside air will deposit in the hold.
A guide of when to ventilate can be found by measuring the dew point of the air in the hold and if this is higher than the air outside, then ventilation should take place. Changing the air in the hold in this case will ventilate the cargo space with little risk of condensation occurring.
Ventilation should be restricted if the dew point of the outside air is higher than the temperature of the cargo. To ventilate under these conditions would cause condensation on the cargo when the outside air with a higher dew point comes into the cargo space.
The temperature of the air both outside and in the holds should be regularly taken, along with dew point readings. By knowing these figures, the decision of whether to ventilate or not can be taken.
However, ventilation only affects the surface of the stow, thus only removing heat from the top. Owing to the nature of soya bean cargoes, changes in temperature and humidity at the surface of a fully laden hold will not be felt throughout the hold; changes at the surface of a grain type cargo will not be felt by the material at the centre of the hold. It follows then that the condition of a grain type cargo, with the exception of the surface layers, will be almost entirely dependent on the condition of the cargo at the time it was put into the hold.
Thus, ventilation can be carried out at all times that the dew point or temperature determinations indicate, and this practice should be followed to maximise ventilation and reduce risk of damage at the surface of the cargo. It is not necessary to cease ventilating during the day or night, unless the outside air is unsuitable in terms of dew point or adverse weather / sea conditions are imminent.
Often the shippers do not provide any information to the ship on how to stow and protect the cargo, leaving this to the Master’s discretion (subject to charter provisions between owners and charterers). The aim of ventilation is to minimise any adverse changes that might result in moisture damage to a cargo. A question may therefore arise as to whether a vessel carried out sufficient ventilation of the cargo and whether any of the alleged damage could be attributed to the ventilation strategy adopted.
The vessel should always record the ventilation strategy followed:
Fumigation of soybean cargo may be required because of insect infestation found at loading, compliance with contractual specifications, or to issue a phytosanitary inspection certification. Voyage times between countries where soya beans are grown and countries where soybeans are in demand, can range from three to six weeks. Rather than undertaking a lengthy fumigation at the port of origin, soya beans are normally fumigated on passage. Recently, it has become apparent that fumigators are requesting much longer fumigation times than has previously been the case. during the voyage.
- Self-heating / Spontaneous combustion
- Mechanical influences
- Toxicity / Hazards to health
- Shrinkage / Shortage
- Insect infestation / Diseases