Tea consists of the fermented and dried leaves, leaf buds and tender stems of the evergreen tea bush of the Theaceae family. Tea is a high quality semiluxury item, the stimulant action of which results from its content of 2.5 - 5% of thein. At certain intervals, the tea bushes are cut back to a height of 1 m. Tea is always harvested as two leaves and one bud. Tea is cultivated in plantations (tea gardens).

The principal tea cultivating countries are in the tropics and subtropics. Unlike green coffee beans and raw cocoa, tea is exported in ready-to-use form. It is a cargo which demands the utmost care. Shipping period starts approx. 6 weeks after harvest, with the tea shipped at the beginning of a season being the most valuable. Later varieties of tea are mostly of lower quality. The crop is harvested all year round, with the following exceptions:

Green tea: With green tea, the freshly picked leaves are steamed, rolled and dried so that the green color of the chlorophyll is retained. The fermentation process is omitted.

Figure 1: Processing flowchart for green tea

Figure 2: Processing flowchart for black tea 
(processing in country of production), 
"orthodox" production

CTC differs from orthodox production solely in that, after rolling and before fermentation, the tea is uniformly shredded with a CTC machine, so shortening the overall production time by approx. 50%. This method yields powerfully flavored, quick brewing teas which, while they are not of very high quality, are particularly suitable for producing tea bags.

A distinction is drawn between the China tea plant (e.g. from China, Japan and Taiwan) and the Assam tea plant (e.g.. from India, Sri Lanka, Indonesia and Vietnam), each variety yielding both leafy and broken grades of tea. Teas are also classified and graded depending upon the size of the tea leaves. The youngest, small top leaves (= pekoe tips) provide the most valuable teas, while the older, large bottom leaves provide less valuable grades.

The product may be shipped as soon as 3 - 4 weeks after harvest, but 1.5 - 2.5 months may elapse before shipping. The tea shipped at the beginning of the season is the most valuable. Shipping tea later after harvest than this may result in quality degradation during transport, which may particularly affect the light southern Indian tea.

Otherwise, tea has a long storage life of 18 months or more provided that proper transport and storage conditions are maintained. However, this does not apply to aromatized teas.

Figure 3: Tea gardens in Grusinia



Figure 4: Tea plant in Grusinia, a highland tea: in order to make picking easier, the evergreen tea plant, which can grow to a height of 4 - 20 m, is kept as a bush.

Figure 5: Tea branch



Figure 6: Tea grades as a function of leaf size

1 - Pekoe tip, thin, wiry, often with a light covering of silky hairs

2 - Slightly twisted, often with white to golden yellow tips

3 - Somewhat coarser leaf

4 - Coarse leaf

5 - Very coarse leaf

Figure 7: Assam tea

Figure 8: Finest Ceylon harvest F.P. (flowery pekoe leaf grade)

Figure 9: Darjeeling tea: a black, fragrant tea from northeastern India, one of the best varieties of Indian tea [Bramah Tea and Coffee Museum, London]

Figure 10: Formosa oolong tea: a black, semifermented tea from Taiwan which has the largest leaf size. It provides a light, peach-flavored infusion [Bramah Tea and Coffee Museum, London].




Figure 11: Green tea from China: Phi Mu Tan




Figure 12: Bird's nest of green tea: tea store in San Francisco




Figure 13: Bamboo cane containing pressed tea: China Yunan Famous Aroma Bamboo




Figure 14: Tea brick



Figure 15: Preparation for tea tasting: more than 250 grades of tea must be tasted each day by the tea taster [Speicherstadt, Hamburg].

Figure 16: Tea chests, which are usually made from plywood, are reinforced at the corners by strips of metal [Bramah Tea and Coffee Museum, London]



Figure 17: Tea chests from Japan: the aluminum foil can be seen at the top of some of the chests [Bramah Tea and Coffee Museum, London]



Figure 18: Japanese green tea; the Japanese account for 80% of consumption. These sales packages each hold 30 tea bags [Bramah Tea and Coffee Museum, London].

China tea is also shipped in tinplate containers which are sealed with solder and additionally wrapped with bast mats.

Sample chests are marked with a cross and a special stamp to indicate this status. Sample chests must be stowed separately and accessibly. Tea chests which have been additionally packaged and sealed in the country of origin are described as "country coopered packages", while those which are so packaged only on arrival at the port of destination are described as "dock coopered packages" [50].

Ship, truck, railroad, aircraft (transport of sample chests to port of destination for purposes of comparison). Tea, especially Darjeeling, is increasingly being transported by air and is known as "air freighted" tea.

Tea is predominantly transported in standard containers. Containers intended for loading have to be watertight and must not be contaminated in any way. Containers whose floors release a foreign odor, are contaminated by any substances or are too damp should be rejected. Below deck stowage is required, to rule out the possibility of exposure to rain or seawater or of overheating by day and cooling at night. Tea in containers should be stowed away from sources of heat.

Carton dimensions are adapted to container dimensions and allow the containers to be filled virtually to total capacity. These two features mean that the standard container can be used without difficulty as FCL cargo.

Hooks must not be used because they can tear or puncture the chests, resulting in loss of the contents. Do not use slings or cargo nets. Handling on pallets has proved most effective because this reduces the risk of breakage since the chests can be stacked in a uniform block.

Figure 19: Sorption isotherm for tea, Darjeeling, at 10°C


Figure 20: Sorption isotherm for tea, Lapsang Souchong, at 10°C


Figure 21: Sorption isotherm for tea dust at 15°C

Tea is extremely sensitive to moisture/humidity. Moisture, for example due to rain, seawater or condensation water, results in mold growth and mustiness. Moldy or musty tea is unusable, its musty flavor making it worthless.

Tea chests require dry holds with good ventilation facilities and must not exhibit any damage due to sweat. Dripping sweat causes severe soiling of the tea chests, the contents of which must then be repackaged. Dunnage must accordingly be carefully laid in the hold and the ship's sides covered with mats, so that the tea chests cannot come into contact with steel parts. Mats or packaging paper must be laid over the chests at potential drip points.

Moisture damage may even originate during processing. Tea chests which have come into contact with water become speckled or the uppermost layer of chests becomes uneven.

If moisture damage is suspected, testing is performed using the silver nitrate method, to find out whether chloride solutions (seawater) or fresh water (condensation or rain) are the cause.

The water content of black tea must not fall below 2%, as the product otherwise becomes hay-like and its essential oils readily volatilize, while on the other hand, it must not exceed 9% [2] as it then has a tendency to grow mold and become musty.

The wood of the chest should have a water content of 10 to at most 12%, corresponding to an equilibrium moisture content of 60 - 70%. The same applies to any wooden flooring/ceiling in containers/holds.

Tea requires particular temperature, humidity/moisture and possibly ventilation conditions (SC VI)(storage climate conditions).

If the product is at "shipping dryness", i.e. if there is no risk of degradation by mold etc. due to water content, ventilation is not required. If this is not the case, the following ventilation measures should be implemented:

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

Protect from odor tainting by ventilation equipment (see RF Odor).

It belongs to the class of goods in which respiration processes are suspended, but in which biochemical, microbial and other decomposition processes still proceed, which, especially as a result of postfermentation, are associated with consumption of O₂ and evolution of CO₂.

Tea chests are extremely sensitive to mechanical stresses. The very thin plywood sheets from which they are made break, burst and tear under even very slight stresses and such breakage then generally damages the internal aluminum foil and parchment paper resulting in losses of aroma and reduced tea quality.

Use of hooks must be prohibited because they can tear or puncture the chests, resulting in loss of the contents. In order to avoid causing damage, chests should also never be transferred with slings or cargo nets, but should instead be handled on pallets.

Mechanical damage is often caused by exceeding stack heights. When in intermediate storage, 50 kg chests may be stowed 5 high. However, on board an ocean-going vessel or in containers, they should only be stowed 4 high (stack height approx. 2 m) as they are subjected not only to static loads, but also to dynamic stresses (mechanical stresses) due to the motion of the ship/handling operations. Total loss generally occurs at stack heights of 7 - 8 units. According to [11], palletized chests should be stacked no more than 3 high. Pallets holding chests must not be overstowed with other pallets.

Frequent handling or severe mechanical stresses (e.g. due to excessive stack heights) may result in breakage of the chests and thus loss of volume.

Chests of tea are at particular risk of infestation by pests (e.g. tobacco beetles, copra beetles, drugstore beetles or cockroaches) during storage at the port before shipping. Storage conditions should thus be investigated at the port of loading. If beetle infestation is suspected, one or two tea chests should be selected from each batch in the warehouse. These chests should then be wrapped in two or three layers of oiled paper, with the seams being sealed with adhesive tape. Once wrapped, these chests should be stowed separately from the remainder of the tea cargo. If beetle infestation is then observed in the main batch at the port of discharge, the sample chests may provide an indication as to whether infestation occurred before loading (samples also infested) or after loading (samples not infested). If no assessors are available, this measure may serve as a stopgap. The cargo must also be inspected for attack by rats and mice.