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.
There are two methods of processing the coffee berries. The first method is wet processing, which is usually carried out in Central America and areas of Africa. The flesh of the berries is separated from the seeds and then the seeds are fermented – soaked in water for about two days. This dissolves any pulp or sticky residue that may still be attached to the seeds. They are then washed and dried in the sun, or, in the case of commercial manufacturers, in drying machines.
The dry processing method is cheaper and simpler, used for lower quality seeds in Brazil and much of Africa. Twigs and other foreign objects are separated from the berries and the fruit is then spread out in the sun on cement or brick for 2–3 weeks, turned regularly for even drying. The dried pulp is removed from the seeds afterward.
After processing has taken place, the husks are removed and the seeds are roasted, which gives them their varying brown color, and they can then be sorted for bagging.
There are three coffee shrub varieties of commercial importance, viz.:
- Coffea arabica, the Arabian shrub, being a “highland coffee”, having a greenish to blue-green color and strong full flavor; caffeine content of approx. 1,2%.
- Coffea robusta, the robusta coffee shrub, being a “lowland” coffee, having small, roundish beans which are generally brownish to yellow green coloured; caffeine content of approx. 2,3%.
- Coffea liberica, the Liberian coffee shrub, being a lowland coffee, of which the beans are larger than of the Arabica coffee, but are regarded inferior to the Arabica shrub because of the sharp flavor.
In addition to these varieties, a distinction can also be made between ‘unwashed’ and ‘washed’ green coffee beans, the latter generally involving coffee beans of higher quality grade, but also more suceptible to moisture damage due to their hygroscopicity.
Coffee Grading (SCAA method)
Specialty Grade Green Coffee:
Specialty green coffee beans have no more than 5 full defects in 300 grams of coffee. No primary defects are allowed. A maximum of 5% above or below screen size indicated is tolerated. Specialty coffee m ust possess at least one distinctive attribute in the body, flavor, aroma, or acidity. Must be free of faults and taints. No quakers are permitted. Moisture content is between 9-13%.
Premium Coffee Grade:
Premium coffee must have no more than 8 full defects in 300 grams. Primary defects are permitted. A maximum of 5% above or below screen size indicated is tolerated. Must possess at least one distinctive attribute in the body, flavor, aroma, or acidity. Must be free of faults and may contain only 3 quakers. Moisture content is between 9-13%.
Exchange Coffee Grade:
Exchange grade coffee must have no more than 9-23 full defects in 300 grams. It must be 50% by weight above screen size 15 with no more than 5% of screen size below 14. No cup faults are permitted and a maximum of 5 quakers are allowed. Moisture content is between 9-13%.
Below Standard Coffee Grade:
24-86 defects in 300 grams.
Off Grade Coffee:
More than 86 defects in 300 grams.
Primary Defects are full black, full sour, pod/cherry, large/medium stones, large/medium sticks.
Secondary Defects are parchment, hull/husk, broken/chipped, insect damage, partial black, partial sour, floater, shell, small stones, small sticks, water damage.
The raw coffee bean color
There are many factors within the stage of picking, drying, milling and grading that can affect the outcome of green bean color, and also the quality.
First, the major colors found in caffeinated green beans include:
Note: These colors are those typically used in international standard classification descriptions.
There are other colors found outside the acceptable range. These include blue beans which are usually the result of high moisture content caused by under-drying and, instead of roasting, will bake, resulting in a very flat cup. Yellowish beans are also outside the boundaries of acceptable beans.
This is the most highly desirable color found in the high quality coffee beans. The latter is obtained by means of sun drying after washing. Along the process of sun drying the coffee is allowed to receive the heat in a gradual way, while the coffee beans are set on a drying table and the air is allowed to percolate around the beans in an even manner.
The parchment coffees which generally produce a grayish blue color are normally found intact and whole, hence free from any split and open defective beans after the drying process. The moisture content of these types of beans ranges from 8.5% to 10.5%, in both parchment form and after the hulling.
After hulling and grading, coffee beans retained on screens 16, 18 and 21 are coffees of high density and strictly hard beans and reflect a white center cut in every stage of the roasting profile.
At a medium roast, beans with these characteristics will produce a darkish chocolate color (without over roasting), and slightly shiny without an oily exterior (often caused by over roasting). This is the ideal.
Properly dried beans of a grayish-blue color will give a well balanced acidity, full body and a rich flavor free from any aftertaste.
Rapid coffee drying will give a parchment that splits open in the final drying process. The same process will also affect the grain, creating a brownish tinge around the edges. In addition, some of the beans will fade, resulting in a whitish to yellowish color and light in density. In the final analysis rapidly dried coffees have characteristics of light acidity to somewhat lacking acidity, light body and a flat flavor in the cup.
This is another category of coffee beans which are normally found to be fairly solid in formation, and high density. Grayish-green beans are usually well dried and free from open parchment.
Beans with these characteristics are commonly found within the coffees that come from South America, Central America, Papua New Guinea and Hawaii.
Grayish-green beans at the medium roast profile will produce a brilliant chocolate color. The cup analysis will normally reflect a rich and smooth acidity, heavy body and a mellow flavor.
Brownish-gray-green Brownish-green Brown
Washed green beans which reflect a brownish-gray-green to brown color are the coffees which usually have been picked either at stages of under ripe or over ripe. This color is also formed by scorching heat during sun or mechanical drying, over fermentation. Old warehoused coffee is another factor that can contribute to this type of color variation.
Beans of this type will generally produce a very light acidity, light body and, normally, overly dominant flavors which can include any combination of: woody, earthy, fermented, nutty, slightly harsh, bitter, greenish, grassy, potato and medicinal.
These characteristics are often masked by a very dark roast to add body and deaden strong undesirable flavors.
Coffee beans must be hard and not spongy (especially washed coffee beans), i.e. no trace should be left if a finger nail is pushed into the beans. Clean processing is indicated by gloss and smoothness of the coffee beans.
Shipment / Storage
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. Coffee 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.
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.
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.
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.
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.
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.
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.
Coffee is normally shipped as green beans and is prone to water absorption and desorption.
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.
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.
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.
Additional information on coffee:
a) Main reason for wetness is direct wall contact with the cargo. Hence use 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.
d) Minimum claims creation can only be ensured by changing shipments to CY/CY status, which is only feasible for certain selected areas of origin (with respective infrastructure given for shippers).
e) It does also 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 another 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.