Coffee Beans
| Infobox on Coffee Beans | |
|---|---|
| Example of Coffee Beans |  |
| 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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| Humidity / moisture |
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| Oil content | - |
| Ventilation | Recommended ventilation conditions: air exchange rate 10 - 20 changes/hour (airing). Important: a suitable ventilation program must be drawn up depending upon external temperature, relative humidity, cargo temperature and moisture content of the coffee beans. See text for details. |
| Risk factors | If coffee beans have an excessively high moisture content, there is a risk of mustiness, mold growth and post- or overfermentation. Washed coffee frequently has a higher moisture content than unwashed coffee, due to the processing technique used, so meaning that it also releases more water vapor and is therefore more at risk from sweat. Green coffee beans are extremely sensitive to foreign odors |
Coffee Beans
Contents
Description
A coffee bean is the seed of the coffee plant (the pit inside the red or purple fruit). Even though they are seeds, they are referred to as 'beans' because of their resemblance. The fruits, coffee cherries or coffee berries, most commonly contain two stones with their flat sides together. In a crop of coffee, a small percentage of cherries contain a single bean, instead of the usual two. This is called a peaberry. Coffee beans consist mostly of endosperm that contains 0.8 - 2.5 % caffeine, which is one of the main reasons the plants are cultivated. As coffee is one of the world's most widely consumed beverages, coffee beans are a major cash crop, and an important export product for some countries. It is considered a regularly consumed beverage in the United States - as popular as soft drinks and even water - and because of the volume consumed, it is there that coffee is highest in demand.
Coffee beans are sensitive to moisture and are usually shipped in woven bags made from natural fibre which allows free circulation of air. These bags are vulnerable to hook and handling damage. Woven polypropylene bags have been available for a considerable time but their usage for imports of green coffee to Europe is limited and is not acceptable unless special arrangements have been made between buyers and sellers. Their smooth surface tends to make them slip in the stack and although they are more resistant to light external wetting, they do absorb heavy moisture, thus allowing the water to penetrate to the centre of the coffee, whereas the fibre bags tend to hold water at the surface, thus confining damage to the outer layer of beans. Most types of polypropylene bags do not produce a positive stain on being wetted and the close flat weave does not permit the same air circulation as the fibre bag. Coffee beans and the fibre bags in which they are packed readily become tainted by proximity to strong smelling goods. It is necessary to distinguish between coffee which has been so contaminated and fermented coffee which may produce a strong aroma. Coffe beans are subject to loss in weight, normally accepted as 0,5%, but varying between shipments. This problem is overcome by comparing the weights of torn or damaged bags with the average weights of sound bags rather than with their shipped weights.
There are three varieties of coffee shrub which are of economic significance:
1. Coffea arabica, the Arabian shrub.
Plantations are generally at altitudes of over 1000 m, which make it a "highland coffee". The average length of coffee beans of this variety is approx. 9 mm and their color is greenish to blue-green.
The coffee beans of this variety are more expensive, the higher the plantations, as the fruits ripen more slowly at greater altitudes, becoming horny and hard and containing only little moisture. They consequently have a strong, full flavor. They have a caffeine content of approx. 1.2%. This variety accounts for 75 - 80% of the world's coffee harvest.
2. Coffea robusta, the robusta coffee shrub.
This is a "lowland" coffee, as its plantations are as a rule below 1000 m. The beans of this coffee variety are small, roundish and generally brownish to yellowy green. The coffee cherries ripen more quickly and their beans have a higher water content than highland coffee and generally have a less powerful flavor. They have a caffeine content of approx. 2.3%.
3. Coffea liberica, the Liberian coffee shrub.
A lowland coffee, whose beans, though larger than those of Coffea arabica, are less highly regarded because of their sharp flavor. In addition to these varieties, a distinction is also drawn between two methods of processing green coffee beans: the dry process (produces unwashed green coffee beans) and the wet process (produces washed green coffee beans):
Unwashed green coffee beans
This processing technique is used in particular in Brazil, which is a coffee-producing country. The majority of the world's coffee production is dry-processed.
Unwashed green coffee beans
This processing technique is used in particular in Brazil, which is a coffee-producing country. The majority of the world's coffee production is dry-processed.
Flowchart illustrating the dry process
Washed green coffee beans
The washed varieties are generally those from the higher quality grades. However, their higher hygroscopicity makes them more susceptible to moisture damage
Flowchart illustrating the wet process
Quality / Duration of storage
Green coffee beans are graded according to certain criteria, such as shape, size, uniformity of the beans, color, horniness, husk, cut, gloss, smoothness of the beans, proportion of defective beans, foreign matter and odor.
For instance, beans should be graded into uniform shapes and sizes. A distinction is drawn between flat beans (2 beans in a cherry), peaberries (only 1 bean in a cherry, not flattened) and Maragogype coffee (particularly large beans).
The color of the beans must exhibit a greenish to deep green and fresh background hue and varies depending on variety and origin (top varieties from Central America: strong green to gray-blue, other varieties: light yellow to light green).
Fading color, starting at the tips of the beans, results from a relatively long storage time and is deemed to indicate poor quality. Fresh-colored coffee beans are recently harvested, while yellowish-green hues are indicative of beans from an older harvest.
Horniness is also an indicator of product freshness: fresh beans should be tough and have to be peeled with a knife in the manner of horn. The cutting test shows that highland coffee is hard and has a horny, tightly serrated and wrinkly cut surface. A straight, broad, open cut indicates lowland coffee.
Coffee beans must be hard and not spongy (especially washed coffee beans), i.e. if a finger nail is pressed into the bean, it should leave no trace.
The gloss and smoothness of the beans indicate clean processing.
In addition, the proportion of defective beans and foreign matter constitutes an important criterion in the quality grading of coffee. Thus, the highest quality green coffee is sorted (previously hand-sorted, now sorted by machine) and contains only a few defective beans. Foreign matter, such as sticks, stones and leaf residues, has been almost completely removed, while medium quality green coffee still contains a considerable proportion of defective beans and foreign matter.
Overview of typical green coffee defects:
| Designation | Cause | Appearance | Odor/Flavor |
| Sour or waxy beans | starting to rot due to overfermentation, the most dangerous coffee defect | yellowish to brown, often with mottled surface, glassy | repellent, rotten, rancid |
| Frosted beans, also known as stinkers | frost at sunrise, also night frosts | speckled or black, somewhat spongy | acrid and stinking |
| Quakers | unripe fruits | underdeveloped, shimmery green to grass-green, firmly attached silver skin | sharp, sour or grassy/pea-like |
| Broken beans | damage during processing or transport | fragments | same as whole beans |
| Broken beans | -1 to +4°C | 75 - 80% | 1 - 2 months |
| Insect-damaged beans | insect bites and chewing | holes or chewed edges | same as undamaged beans |
| Ear-shaped and deformed beans | beans damaged during hulling | ear-shaped, hollow beans | weak aroma |
| "Triplets" | three-seed beans | flat sides beveled | as normal beans |
| Elephant beans | several beans fused together | ||
| Foreign matter | contamination due to stones, sticks, small lumps of earth etc. |
The following terms allow conclusions to be drawn as to the quality of the coffee:
Ship fillings: coffee spilled on the floor of the hold; before delivery, the ship should clean and bag this coffee (or pay to have the above operations performed).
Ship sweepings: highly contaminated coffee lying on the floor of the hold (not generally fit for recovery). ship samples: coffee samples taken shortly before loading onto the ship or during loading operations (deposited at the port of loading).
Ship spills: coffee gathered up using clean shovels, without having come into contact with the floor.
Shipper's slacks: bags recorded by the ship as being too weak when loaded.
Skimmings: damp coffee from partly wetted bags; the coffee beans may be divided into good skimmings, medium skimmings or poor skimmings.
Quality specifications for coffee vary very widely in Europe. Basically, the darker the coffee is roasted, the lower is the required starting quality. If German quality requirements are taken as a baseline of 100%, the coffee qualities required in Scandinavia are between 110 and 120%, while Southern Europe demands qualities of between 60 and 70%, i.e. a loss causing depreciation of 20% in Germany does not constitute a loss at all in southern Europe.
Washed coffee may be stored for several years if the recommended storage conditions are complied with.
Applications
As a semiluxury item: green coffee beans are roasted, ground and brewed. They are further processed to yield products such as (freeze-dried) instant coffee.
Shipment/Storage
Coffee beans are usually packaged in new bags of woven natural materials (e.g. jute or sisal), which allow free air circulation. Their net weight is generally 60 kg, but may be 69 kg in Central America/Colombia.
Coffee from Mexico is sometimes shipped in a sisal outer bag containing a plastic inner bag. This plastic inner bag is perforated. Woven plastic bags, as are occasionally used for transport from West Africa, have no effect on the quality of the coffee, provided that they are air-permeable.
Water damage
Wet damaged bags will normally exhibit external staining with associated mould damage, discolouration or bleaching of the beans under the area of the stain. Where the damage to the content is limited to beans near the surface of the bags in the area of the stain, it is often possible to recondition these bags, re-bagging the sound content in clean bags and selling off the extracted mouldy beans. Although this involves the expense of reconditioning, it is often more profitable than selling the bags as lying. A simple chemical test on a section of the bag fabric will determine whether the wetting agent was sea or fresh water. Lightly rain-wetted bags, especially at the point of loading, often show a slight yellowing of the bag surface with small areas of mildewed beans immediately below the surface. Long standing severe wet damage can give rise to black, rotting bag fibres with solid coagulations of mouldy beans below the surface. This may either be associated with a heavy wet damage at the time of loading or excessive sweat damage due to condensation in the hold at the early stages of a long voyage. Only experience and observation can establish whether pre-shipment or transit damage is involved. In the event of water damage being detected with break-bulk (non-container) shipments it is vital that the hold condition be established as early as possible, namely the position of the damaged bags in relation to the coffee cube in general e.g., in the upper, lower or extreme sides of the cube and the position relative to hatch openings and air vents.
Where containers are involved, the same criteria apply as above but special attention should be applied to the position of the damaged bags relative to the doors, roof and vents of the container. Wherever heavy damage is involved it is of utmost importance to establish the condition of the container on arrival and check for holes in the roof, defective door seals and other damage.
Country Damage
A term commonly given to damage which occurs in the country of origin prior to the bagging of the beans. It is sometimes possible to prove country damage by establishing that the damaged beans are scattered at random through the bags which will probably show no signs of external staining. However, it is necessary to appreciate that light transit damage may give a similar effect where the bags have received considerable handling subsequent to being wetted.
Indonesian Natural (Unwashed) Coffee
There may be white or dark brown beans mixed in this coffee, being a characteristic of the commodity. Another characteristic of this coffee is a leguminous and earthy smell which is due to the climate, the condition of the soil and humidity in the atmosphere. This smell is similar to the musty odour of water damaged coffee but in the case of Indonesian Natural Unwashed Coffee this odour is not, itself, evidence of water damage.
Decaffeinated Coffee
This is treated coffee which is now being exported to various ports around the world. The natural appearance of this coffee is of a blotchy nature and, due to the relatively low moisture content, it is of a brittle nature. Care should be taken when surveying or examining such coffee to distinguish between actual damage and the natural appearance. When extracted with methyl chloride, decaffeinated beans are brown in colour as opposed to the normal bean colour green.
Soluble Coffee
Occasionally soluble coffee is stowed with green beans from Brazil. When shipped on pallets or, in extremely rare cases, as loose cargo, the nature of the packing of the soluble coffee precludes it from contaminating any other cargo or being contaminated by any other cargo unless the cardboard cartons and inner polythene bags are themselves damaged. Such damage to the packing may occasionally lead to contamination of the bags containing green beans by the soluble coffee, which due to its hygroscopic nature gives the appearance of the bags being damaged by a tarry substance. Such bags are not normally treated by receivers as being in damaged condition unless the degree of contamination is such as to penetrate the bags and render the beans unsuitable for roasting.
Infestation
Coffee occasionally exhibits infestation on arrival. This may be due to insufficient fumigation at the point of origin but may also arise from cross infestation from other cargfo or residues left in holds or containers. The problem is usually solved by further fumigation at destination.
Shipping Documentation
Coffee is covered by an International Coffee Agreement. Almost all producing countries together with the major consuming countries are members. Under the Agreement, export quotas may be established and are controlled by the necessity of providing specific documentation upon import into consuming member countries. Where coffee is to be sold by salvage sale, it is important to ascertain which, if any, documentation is available as this may affect the residual value. This is particularly relevant to coffee lying in free ports.
Shipping Advice
Coffee is normally shipped as green beans and is prone to water absorption and desorption. There are two main types of coffee : Robusta and Arabica.
Coffee is packaged in hessian/jute/poly lined bags or in bulk inside containers. In the latter mode a plastic inner liner is fitted into the container to hold the bulk for sanitary reasons. Condensation damage, taint and infestation are the main risks associated with carriage and loss of quality. It is essential that containers are properly prepared in order to achieve good quality transport out-turns as follows:
Coffee In Bags
In GP containers
Floors and side walls to be covered with corrugated kraft-paper, cardboard, or a double layer of single paper. Special care required at container corners. Corrugation ribbing (rough side) must face the container walls, on floor and sides, except on top and facing the door where reverse applies. Depending on the season and transport route "Dry Bag" desiccants to be added for condensation control. Containers fitted with passive vents must have the vents taped off on the inside of the container to prevent moisture development.
In High Vents
There are two types of high vents namely all steel inner or plywood sheathed. Floors to be covered with corrugated kraft-paper, cardboard, or a double layer of single paper. The bare steel version should be lined with corrugated kraft paper, cardboard, or a double layer of single paper between the upper and lower vents on the side panels, front panel and on the doors. Both versions should have similar protection in way of the corner posts. After stuffing, depending on the routing and season, paper should be placed on top of the cargo for sanitary reasons. Never use desiccants such as "Dry Bags" in high vents ( Only works in an enclosed space).
In Open sides
Care must be taken to ensure that side curtains are rolled down when on the terminal or on inland transport. Stowage onboard ship must be underdeck and with the curtains rolled up. No paper is to be placed on the floor as moisture is easily absorbed in this environment. Wooden gratings or pallets must be placed on the floor to avoid possible moisture damage to the bottom bags (only seasoned wood is to be used).
In Integral reefers
This equipment is used for the transport of high quality so called "Gourmet coffee". The container must be fitted with drain holes to drain away moisture. Recommended temperature setting is plus 13 degrees Celsius and with no air freshening, or plus 14 degrees Celsius with 10 per cent air freshening. Written transport instructions must be obtained form the shipper prior to accepting this cargo due to the very high value involved.
Coffee In Bulk
Polypropylene inlet (linerbag) large enough to fit into the sidewall corrugation ribs. For a standard 20ft GP the bag should be of minimum dimensions: 550 cm (length) x 234 cm (width) x 240 cm (height). Linerbag to be properly attached and fixed horizontally at the top ( avoid torsion in the bag so that tearing does not occur during loading).In order to contain the coffee bulk, either an independent or integrated bulkhead must be fitted in way of the door in such a way that closing of the doors is possible on completion of blowing in the load (at least 10 cms clear of the door).Where an integrated bulkhead is not part of the bag construction, enough material should be left to cover the inlet openings. Positioning the bulkhead can be achieved by integrated nylon webbing straps, or horizontal steel/wooden bars fitting into the doorway recess. Wooden bars must always be of seasoned timber. Prior to loading the coffee, blow the bag into position and close one door for safety. Depending on the season and transport route "Dry Bag" desiccants to be added for condensation control. They must be placed within the inner liner on top of the stow and taped on cardboard floaters (to avoid immersion in the load during transit). Affix a warning sticker to the door close to the seal as per fig. Manifests must clearly state that contents of the container is in bulk.
Container transport
The protective and ventilation measures conventionally taken in a general cargo ship do not generally apply to containers.
Containers have increased handling speeds decisively. The constant increase in container ship tonnage has increasingly reduced the supply of space in conventional ships. Approx. 95% of European coffee imports are already transported in containers - the change-over to containerized coffee transport is largely complete.
Two types of container are used to transport coffee:
1.) Standard containers
Standard containers differ in the materials used for wall and ceiling construction. Corrugated steel sheet, fiber glass-reinforced plastics and, occasionally, plywood, are used. The floor always consists of wood or perforated pressure plate.
To simplify opening and closing of the containers, standard containers have a few small "ventilation holes", which have no ventilation effect but merely equalize pressure differentials on opening and closing of the containers.
A standard container stuffed with coffee should be stowed below deck. The extreme temperature differences on deck (up to 60°C between day and night) could result in container sweat during maritime transport.
In addition, a sharp drop in temperature in the container caused by the effects of the wind and weather of a northern winter may result in considerable container or cargo sweat. Below deck, these effects are considerably reduced.
The bottom, sides and top areas of the cargo block in the container should be lined with packing paper. Incipient container sweat (initial drips) may be soaked up and distributed by the paper.
2.) Ventilated containers ("coffee containers")
Ventilated containers have ventilation openings over the entire length of their side walls in the floor and roof areas. This ventilation is passive, i.e. the ventilated containers have to be actively ventilated from outside. Active ventilation can only take place when the hatch is closed. Upwardly directed air flow may be produced by extracting the hold air at the top and supplying fresh air in the area of the hold floor. This air then also flows through the ventilated container. This is the only way to ensure ventilation in the ventilated container.
Container ventilation
Because the ventilated containers are ventilated in this manner, they must be loaded below deck. On deck, the airflow through such containers might not be sufficient and the containers would also be exposed to considerable temperature fluctuations. Furthermore, on deck the additional ventilation openings in the container create the risk of seawater spray deposition.
The container floor should be lined with paper. There must be no dunnage at the sides and in the top area, since the ventilation action would otherwise be impaired or completely prevented.
The wooden flooring of the containers must be absolutely clean. If washed, it must be completely dried; the water content of the flooring should be 12%, corresponding to a lumber equilibrium moisture content of 70%, so that the flooring does not constitute an additional source of water vapor to dampen the coffee cargo and container atmosphere.
Unpacking/stripping of the containers: green coffee beans are stuffed at intrinsic temperatures of 30 - 35°C. Since they are loaded below deck, coffee containers have a core temperature of approx. 18 - 20°C even during the Northern European cold season, due to the short duration of the voyage. If such containers are unloaded at -10°C, speed is of the essence. The more quickly are the containers stripped, the lower is the risk of moisture damage. Long truck or rail journeys should be avoided, since the extremely rapid cooling of the container would inevitably lead to container sweat. A container should where possible be unpacked within 24 to 48 hours of unloading from the container ship. Top and side dunnage cannot prevent wetting damage, but they can delay it. This period of delay may have a crucial effect on whether the cargo suffers damage or survives transport without damage.
"Bulk containers": Approx. 1/3 of containerized coffee is transported as bulk cargo in 20' standard containers. Liner bags of plastic fabric are suspended in the containers. The container and liner bag are filled in a tilted position and both are then closed. The dunnage recommendations for "bulk containers" are the same as those for standard containers.
Alternatively, coffee bags may also be transported on flatracks in ventilated holds. However, handling of the flatracks is problematic, as the cargo is exposed to the ambient atmosphere without any protection.
The containers should be stowed below deck away from heat sources. External meteorological conditions do not then have a direct effect on the containers. They are shielded from the external conditions by the surrounding containers and the ship's walls, so meaning that the hold air, with its temperature and moisture/humidity values, constitutes the decisive external influence. The risk of frost on the one hand and major daily variations in temperature may result in spoilage of the coffee, so stow below deck where possible.
Cargo handling
Hooks must not be used in cargo handling 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.
In damp weather (rain, snow), the cargo must be protected from moisture, since moisture ingress may cause damage.
In order to ensure safe transport, the bags must be stowed and secured in the means of transport in such a manner that they 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.
Attention must also be paid to stowage patterns which may be required as a result of special considerations, such as ventilation measures.
Temperature
Coffee beans require particular temperature, humidity/moisture and possibly ventilation conditions.
| Designation | Temperature range |
| Travel temperature | 0 - 20°C |
| < 20°C |
The goods must be protected from frost (< 0°C).
In general, temperatures should be between 10 and 20°C during transport of green coffee beans.
There is a close connection between fluctuations in the ambient temperature and the formation of condensation water (sweat) in the hold or container. Thus, during a voyage from a hot climate (port of loading, e.g. South America in December, i.e. summer in southern hemisphere) to a cold climate (port of discharge, e.g. Northern Europe in December, i.e. winter in the northern hemisphere) intensive cooling of the cargo is essential. Temperatures gradients of as much as 50°C between "summer in the southern hemisphere" and "winter in the northern hemisphere" are entirely possible. A sudden fall in temperature also leads to a higher probability of condensation water formation below the ship's deck or in the container. The resultant dripping sweat then causes considerable cargo losses. Overintensive cooling of the cargo surfaces may also lead to condensation water formation directly on the cargo (cargo sweat).
Condensation water
For this reason and owing to the close relationship between temperature and humidity in the hold together with the external weather conditions, it is necessary to take daily temperature and humidity measurements (external temperature, hold temperature, relatively humidity), so that an appropriate ventilation program can be drawn up.
Humidity/Moisture
Coffee beans require particular temperature, humidity/moisture and possibly ventilation conditions.
| Designation | Humidity/water content | |
| Relative humidity | 50 - 65% | |
| 50 - 65% | ||
| Water content | 8.5 - 10% | |
| 9 - 12% | ||
| Maximum equilibrium moisture content | 65% |
Preventing the formation of condensation water in the hold is absolutely essential and constitutes the number one priority.
The cargo in the hold (or in the container) should be protected from dripping sweat by placing mats, jute coverings, gunny cloth or similar coverings at a distance of approx. 0.5 m above the cargo surface (where possible). The spacing from the cargo is necessary to ensure adequate ventilation. For this reason, use of tarpaulins or plastic films should be avoided, since the coffee beans may otherwise start to postferment.
Condensation water
According to the sorption isotherm for green coffee beans, beans with an 8.5 - 10% water content are at equilibrium with a relative humidity of 50 - 65%.
If coffee beans have an excessively high moisture content, there is a risk of mustiness, mold growth and post- or overfermentation. Washed coffee frequently has a higher moisture content than unwashed coffee, due to the processing technique used, so meaning that it also releases more water vapor and is therefore more at risk from sweat.
Moisture damage (vapor damage, fresh and salt water damage) does not generally become apparent until several days after the beans have come into contact with water and is then manifested by a musty odor and visible changes to the beans.
Exposure to wetness (excessive humidity, rain, sweat) turns the beans white, and sometimes subsequently black, moldy and swollen. A relatively long period of exposure to wetness results in a musty/rotten odor.
Salt water damage may have been caused by seawater ingress during lighterage (=> seawater test using the silver nitrate method). Bags damaged by sea- or rain water should be rejected. In addition, the salt content of the seawater increases water vapor absorption by coffee beans.
The various types of damage, such as discoloration, swelling, moldiness, post- or overfermentation, always have an effect on aroma and flavor.
Green coffee beans should never be transported in the same compartment in conventional ships as rafted logs (high water vapor release).
It is advisable to monitor the water content of the cargo by sampling.
Moisture contents of coffee beans
Normal loading humidity should preferably range around 12%. Where values are between 13.5 and 14%, i.e. the mold growth threshold of 75% relative humidity has already been reached, it is essential to use ventilated containers, and to ensure very rapid stripping after unloading the container from the ocean-going ship.
Very few exporters dry coffee to a level of 10%. Since the weight of coffee is the basis for trade, tax and duty, in this case special agreements and preparations are required on the part of the exporter. If the water content of coffee is reduced to values below 10%, the structure, flavor and odor of the coffee change (depreciation due to loss of aroma).
The Far East exports coffee at particularly high moisture levels (approx. 14%). Ventilated containers must be used for the purpose of loss prevention. Stripping must be performed very quickly, especially in winter in the northern hemisphere.
Ventilation
Coffee beans require particular temperature, humidity/moisture and possibly ventilation conditions.
Recommended ventilation conditions: air exchange rate 10 - 20 changes/hour (airing).
Important: a suitable ventilation program must be drawn up depending upon external temperature, relative humidity, cargo temperature and moisture content of the coffee beans.
The beans constantly release water vapor during the voyage, and the water content may fall by 0.5 - 1%. This released water vapor must be removed to the outside by suitable ventilation in order to reduce the risk of condensation in the event of unfavorable ambient conditions (e.g. sudden drops in temperature of the external air). Intensive cooling must be provided, especially during voyages into cold climates. A sudden drop in temperature causes sweat to form below deck. Considerable damage may be caused by dripping sweat. Overintensive cooling of the cargo surfaces after a sharp drop in temperature may also lead to sweat formation directly on the cargo.
The elevated relative humidity in the hold may also lead to mold damage.
Container transport of coffee beans
In the event of a sharp drop in external air temperature, any consequent rapid impact upon the holds and thus upon the containers may be alleviated by reducing or completely ceasing ventilation. In the event of a sharp decline in the temperature of the hold air, the ceilings and free wall surfaces of the containers are particularly prone to cooling. If the air above the cargo has a relatively high water vapor content (which occurs with goods with a high water content), it must be expected that condensation will form to a particular degree on these surfaces.
In winter, the containers are sometimes exposed to extreme temperature differences during unpacking, as they move from the relatively protected environment of the hold into the sometimes substantially cooler external air ashore. The consequence is a rapid rise in the relative humidity in the container, which may very quickly lead to the formation of condensation. For this reason, the containers should be unpacked or placed in appropriately protected storage immediately on arrival at the port of discharge.
Biotic activity
Coffee beans display 3rd order biotic activity.
Respiration processes are essentially suspended, but biochemical and microbial processes continue. Despite the fermentation process, the embryo is preserved: the loss of the ability to germinate has an unfavorable effect on the contents and thus on the quality of the green coffee beans.
Inadequate ventilation may result in fermentation and rotting of the coffee beans as a result of increased CO2 levels and inadequate supply of atmospheric oxygen.
Gases
If ventilation has been inadequate (frost) or has failed owing to a defect, life-threatening CO2 concentrations or O2 shortages may arise. Therefore, before anybody enters the hold, it must be ventilated and a gas measurement carried out.
Risk factors
Self-heating / Spontaneous combustion
No risk.
Odor
Active behavior: Extremely slight unpleasant odor. Green coffee beans release a peculiar odor. "Fruity" smelling coffee beans have been loaded when very fresh (not to be confused with beans tainted with a citrus odor).
To test the odor of coffee, rub it between the hands. Good new crop coffee smells fresh and leguminous. Poorly processed green coffee beans or those which have been stored in damp conditions smell musty.
Passive behavior: Green coffee beans are extremely sensitive to foreign odors. The specific intrinsic odor of an individual coffee variety may even taint other varieties. Thus, for example, "Minas" coffee (origin: Brazil) has a sharp, carbolic odor, and "Rio" coffee has an iodoform-like odor. These "hard" coffee varieties may odor-taint "softer" varieties (e.g. "Santos" coffee).
The causes of foreign odor may be:
Foreign odor from other goods, such as fish meal, raw sugar, pepper, citrus fruits, hides, furs, chemicals (citrus odor not to be confused with the fruity smell of very fresh coffee beans) inadequate deodorization of storage spaces and ships' holds and of containers
In container transport there are two causes of odor taint:
the container was contaminated at the time of loading (e.g. by previous damaged chemical cargo) and odor may be transferred from the hold to the coffee, at least in the case of a ventilated container.
Since the responsibility for the cleanliness of a container to be loaded is delegated to very low level, there is a greater risk associated with using a container.
Contamination
Active behavior: Coffee does not cause contamination. Some dust may fall out of the porous jute bags.
Passive behavior: Green coffee beans are extremely sensitive to contamination and must be kept absolutely clean. They must be protected from cement and coal dust, as this penetrates through the jute bags used and cannot thereafter be removed from the beans by machine.
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. Exposure to moisture in particular increases the susceptibility of jute bags to rotting, which reduces their mechanical strength.
Toxicity / Hazards to health
Where a cargo has become excessively damp, postfermentation leads to CO2 development; thus, before anybody enters the hold, it must be ventilated and the gas content of the air must be checked. There is a possibility of an oxygen shortage.
Black spots resulting from the formation of condensation water may be caused a mold containing the toxin ochratoxin A, which is suspected of being carcinogenic. This mold is extremely heat-resistant and is not destroyed even by roasting (160°C). It may occur in grain, pasta, spices, wine and beer. Coffee roasters must ensure that the green product is fit for use (max. permitted level 3 micrograms / 1 kg foodstuff).
Shrinkage / Shortage
Weight loss caused by the release of water vapor during the voyage may amount to up to 0.5%. Loss of volume may also be caused by tears in bags.
In addition, weight differences arise through:
- inaccurate weighing in the exporting country
- underfilling of bags
- sampling after filling
- storage after filling and before shipment (release of water vapor caused thereby leads to weight loss)
- tare differences
If very dry coffee is shipped, storage under conducive conditions may even result in a weight increase.
Insect infestation / Diseases
Containers and holds must be absolutely free from insects.
The coffee beetle (Araeocerus fasciculatus) is a typical storage pest, which easily spreads during relatively long periods of storage ashore. Coffee may additionally be infested with cockroaches, rats and mice.
Fumigation is generally carried out in the countries of origin (fumigation certificate), which does not as a rule cause any depreciation. Occasionally, fumigation agents are incorrectly applied to the product and residues with a carbide-like odor are left on the sacking, which may taint the coffee.
Additional information on coffee
1. Shipments
a) Main reason for wetness is direct wall contact with cargo, wherefore can only underline direction of
SOP to ensure use of bubble foil and card board to reduce such contact, however the best way to
avoid this to an utmost extent would be the use of a solid stow method, where like for a chess field
three bags are stowed parallel to the container side walls and three parallel to container front and
back in such a way that the walls are not touched at all. The problem with such method would be
that it would have to be taught to handling staff for several years before taking effect, if followed.
b) Best alternative is the use of big bags, ensuring a minimum contact to container
walls while allowing for a most efficient stow.
c) One cause of humidity inside coffee /cocoa containers is missing air circulation, wherefore it is of
utmost importance to have containers checked upon air holes being free.
d) Minimum claims creation can only be ensured by changing shipments to CY/CY status, which
regrettably only feasible for certain selected areas of origin (with respective infrastructure given
for shippers).
e) Last but not least it does play a major role, at which humidity the cargo is shipped, as most cargoes
are sold on a weight basis and shippers would therefore be tending to ship as humid as possible to
increase their profits. Carriers would -at least for CFS based shipments - then have an interest to
have all shipments spot checked upon the respective humidity levels to avoid excessive claims
ratios, against which they could not defend themselves after CFS B/L's issued clean. So cocoa
should not exceed humidity levels of 6 and coffee not those of 12% - (at least from a pure claims
point of view). Commercial aspects or new technologies might lift this limit upwards with claims
risks usually rising with it.
2. On claims
a) If sweat water claims are filed, it should be considered, whether -apart from proper lining of containers-
shippers have minimized damage risks by shipping at the least humid periods, thereby limiting the
thermo shock when moving into the northern hemisphere (such as the Bay of Biscay for Northern
Europe), i.e. shippers moving cargo in December/January and presenting their sweat water claim
should not be treated equal to those of March/April, as the former should be aware of increased
damage risks.
b) Rarely is sweat water caused by unavoidable climatic changes alone, mostly lack of proper lining,
excessive humidity or taped container air holes are met by lack of due diligence at the receiving
end: such import goods MUST be delivered right upon discharge to avoid major damages, as any
day under cold/wet weather above 0° C is adding an other estimated 2-3%.of damages to the
cargo. Import customer made aware of this cannot then, later, refer to carrier liability or the clean
B/L, if they have failed to take the necessary steps from their end. The same, though, applies to
the carrier, allowing lengthy transhipment storage in any northern European port: he is virtually
stripped of his defence.
Note: Source including Transport Information Service of the GDV)