Cocoa Processing Methods for the Production

of High Quality Cocoa in Vietnam

Breaking of pods

Fermentation of cocoa

Basket fermentations
Heap Fermentations
Box fermentations
Effect of pod storage
The effect of spreading beans after pod breaking
Soaking of beans after fermentation
Summary of fermentation procedures
Drying of cocoa
Quality standards
Construction of solar driers and fermentation boxes
Plans for solar driers
Plans for fermentation boxes. List of figures
Figure Page
1: Temperatures of cocoa in a 50kg basket fermentation

2: Temperatures of cocoa in heap fermentations

3: Temperatures of fermentations in box capacities of 250kg, 100kg, 50kg and 25kg

4: The effect of pod storage on the fermentation temperatures of cocoa.

5: The effect of pod storage and fermentation time on the percentage of fully brown beans in the cut test.


22: A solar drier recommended for the Mekong Delta region of Vietnam with cocoa on the drying bed
23: Cocoa dried by the traditional sun drying methods (7 & 8 days) compared to cocoa dried on a
solar drier (5 & 6 days)

24: Cut test chart for determining cocoa bean quality ACKNOWLEDGEMENTS

The author wishes to thank AusAID and the Vietnam Ministry of Agriculture and Rural Development for
approving the project and AusAID’s funding.

Thanks also to the staff of Can Tho University, Nong Lam University and Western Highlands Agricultural
Science Institute who contributed their time and labour to the project activities.

Department of Science and Technology (DOST) in Ben Tre Province is thanked for their assistance in farmer
surveys and the selection of smallholder sites for solar drier evaluation.

Smilja Lambert of Mars, Inc. is thanked for her assistance with project activities, her technical advice and
liaison with the Vietnamese research Institutes involved.

Success Alliance is also thanked for their assistance in providing information regarding the cocoa industry in
Vietnam and in the establishment of solar driers and fermenting boxes at their demonstration farm sites in Ben
Tre Province HARVESTING OF PODS
After planting of seedlings, cocoa trees usually take about two years before ripe pods start to be produced.
During harvesting, only ripe pods should be picked as beans from unripe pods will not ferment properly. Pods
which are damaged or have fungal infections should be discarded and not included in the harvest. It is best to


BREAKING OF PODS

Pods should be broken with a blunt object such as a piece of wood to avoid damaging the beans. It’s best to
avoid using a knife to cut pods, as beans may also be cut by the knife and this will affect their quality after
fermenting and drying. Pods should not be broken in the rain, as this will wash away the pulp surrounding the
beans and this will affect the fermentation. Beans which are black or have shoots on them or flat beans, which
have not grown properly, should be discarded.

After breaking of the pods, the beans can be spread out in the sun, on a concrete or plastic sheet surface for
approximately two hours (Illustration 3). This allows more moisture loss from the cocoa and a better
fermentation will occur.

Illustration 3: Spreading of cocoa on wire mesh prior to fermentation. FERMENTATION OF COCOA

Fermentation of cocoa can be conducted in a number of manners. The ways it can be fermented include: in
baskets (illustrations 4 & 5), in a heap covered with banana leaves (illustrations 6, 7 & 8) and in boxes
(illustration 10, 11 & 12). In all cases, the bottom and sides of the box or basket should be covered with
banana leaves, however banana leaves on the bottom should be not too thick and should be also perforated
by a knife to make sure that the liquid from the cocoa pulp will be well drained. Insufficient drainage of pulp will
result in a bad fermentation. The top layer of fermenting cocoa should also be covered with banana leaves or
jute bags. This inhibits too much air penetration into the fermenting cocoa also stops too much moisture from
being lost. If too much moisture is lost, the cocoa will not ferment properly. An additional reason for lining the
baskets and boxes and covering the fermenting cocoa is the problem of losing heat by dissipation during the
fermentation. This would cause the cocoa to not attain the high temperatures required for a good fermentation.
Therefore it is very important to cover cocoa beans during a fermentation. Jute bags conserve heat better than
banana leaves, so jute bags or a combination of banana leaves and jute bags are recommended.


Basket Fermentations
25
30
35
40
45
50
012345
Day of Fermentation
Temperature
o
C
Basket, no spreading
of beans prior to
placing in basket
Basket beans spread
before placing in
basket

Figure 1: Temperatures of cocoa in 50kg basket fermentations.

In the two examples given in figure 1, the first had beans placed into the basket straight after pod breaking.
The second treatment had beans spread out on a plastic sheet for two hours prior to placing in the basket.
In both cases, the pods had been subjected to seven days storage prior to breaking.

The second treatment resulted in a much more rapid rise in temperature and this would be better for bean
quality. The first treatment did reach a temperature of 45.3
o
C and this would be considered to be high enough

50
0123456
Day of Fermentation
Temperature
o
C
At Nong Lam
University (100kg)
At Can Tho University
(25kg)

Figure 2: Temperatures of cocoa in heap fermentations

Results of two quantities of beans are presented. The first fermentation was conducted at Nong Lam
University with a quantity of 100kg of wet beans. The second was conducted at Can Tho University using 25kg
of wet beans. In both cases, pods were stored for approximately seven days before they were broken. The
treatment of spreading beans was not conducted but still could be recommended, as temperatures reached
were not very high. The resultant dried cocoa, from these fermentations, was of suitable quality and heap
fermentations can be recommended for farmers who wish to avoid the cost of constructing fermentation boxes.
With heap fermentations, a minimum quantity of 25kg of wet beans is recommended. Quantities, smaller than
this, will not reach high enough temperatures. BOX FERMENTATIONS Illustration 10: Cocoa Fermentation Boxes Illustration 11: Lining of bottom and sides of
In Ben Tre Province (50 & 100kg Capacity) box with banana leaves Illustration 14: Drainage holes, for pulp liquid removal, in bottom of boxes This is the most common type of fermentation conducted around the world and is also used in West Africa.
Box fermentations can be used to ferment quantities of cocoa from 25kg up to any amount a farmer harvests.
For box construction, for different quantities of beans, the following sizes recommended are presented in table
one. Boxes are made from timber 15cm wide and 2.5cm thick. If timber of this thickness is not available, the
boxes can be made of plywood but should be insulated with polystyrene, on the outside, to hold in the heat.
Plans for box construction are given later in the document.

Table 1: Box sizes for fermentation of various bean quantities.
Amount of cocoa Box dimensions (internal dimensions)
Length Width Depth
25kg 33cm 26cm 30cm
50kg 49.5cm 29cm 35cm
100kg 70cm 43.5 39cm
250kg 80cm 80cm 40cm

During fermentation the temperature should be monitored, as is the case in all fermentation methods. In box
fermentations of quantities of beans 100kg or less, turning can be done by hand (Illustration12). In the case of

8
larger quantities of beans e.g. 250kg, partitioned boxes (Illustration 13) are used. In this case, turning of beans
is performed by shovelling them from one side of the partition to the other.

Box Fermentations
25
30

35
40
45
50
0123456
Day of Fermentation
Temperature
o
C
Fresh Pods
Pods stored for 7
days

Figure 4: The effect of pod storage on the fermentation temperatures of cocoa.

During pod storage, the beans within the pod loose moisture. This allows more air to penetrate the cocoa once
the pods are broken and start to ferment. More air causes the fermentation to happen more rapidly and
temperature rises are faster than if pods are broken when they are freshly harvested. Figure four
demonstrates the much more rapid rise in temperature for cocoa pods that have been stored for seven days.
The faster fermentation and temperature rise results in an improved quality cocoa. Therefore pod storage
times of seven to nine days are recommended for farmers in Vietnam.
9
Percentage Brown Beans from Fermentations of Fresh Pods
and Pods stored for seven days
0
10
20

35
40
45
50
0123456
Day of Fermentation
Temperature
o
C
Beans not Spread
Beans spread for 2
hours

Figure 6: The effect of spreading beans for two hours, prior to placement in
boxes, on fermentation temperatures.

The results presented in figure six demonstrate an accelerated rate of fermentation and temperature rise
caused by spreading of the beans for two hours, in the sun, prior to placement in fermentation boxes. In both

10
cases, the pods had been stored for seven days. This demonstrates that this practice will result in a more
rapid fermentation than that obtained from pod storage alone.

Effect of Spreading Beans, prior to Fermentation, on Cut Test
Results in the Dried Beans
10
20
30
40
50


11
Percent Brown Beans in Cut Test
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
567
Day of Fermentation
% Brown Beans
un-soaked
Soaked

Figure 8: The effect of soaking of beans in water, for two hours, prior to drying,
on brown bean percentages
o
C; Day 3, 45-50
o
C; Day 4, 45-50
o
C, Day 5, 40-45
o
C; Day 6, 40-45
o
C. If the cocoa
does not reach these temperature ranges on any given day, a turn should be applied as this will increase the
fermentation and temperature rise. If the temperature drops below 40
o
C from day 4 onwards, the cocoa should
be immediately placed on the dryer, otherwise the cocoa will develop “off” flavours. A procedure of soaking
beans in water, prior to placement on the drier, is also recommended.

During fermentation, when the beans are turned, any clumps of beans should be broken up by hand,
otherwise these beans will not ferment properly. Any pod placenta or other matter, in the beans, should be
removed during the fermentation and turning. 12Illustration 15: Placental material should be
removed when breaking pods and during fermentation.

Towards the end of a fermentation, wet beans can be cut in half and inspected for colour. Properly fermented
beans are brown on the outside (Illustration 16). Over-fermented cocoa tends to turn a blackish colour and

In Vietnam, cocoa grown in the Western Highlands can be sun dried by the methods shown in illustrations 19,
20 & 21 at almost all times of the year. This is because weather conditions are usually dryer than in the
Mekong Delta region.

Illustration 19: Sun drying of cocoa Illustration 20: Traditional sun drying of cocoa
on mats in Dak Lak province in Ben Tre province

Illustration 21: A second traditional sun drying method in Ben Tre province. 14
In the Mekong delta region, the weather is more tropical and higher rainfall occurs. With the traditional
methods of drying demonstrated in illustrations 20 and 21, there is a problem in that the cocoa has to be
shifted undercover during rain and at night. Also, with the basket drying shown in illustration 20, the baskets
need to be moved around during the day to position them in the sun. During periods of heavy rain, the cocoa
may not be able to be sun dried sufficiently and mould contamination will occur. This will lead to a down-
grading of the cocoa and buyers will pay less for it.

These problems can be overcome by the use of a solar drier as shown in illustration 22. These driers use
rocks painted black to collect heat from the sun and vent the hot air through the drying bed. They also have a
roof which can be lowered when it rains and at night and this saves having to move the cocoa around.
Therefore less time and labour is required for drying of cocoa. It is recommended that the drying beds are not
loaded at more than 50kg wet beans per sq. meter. Loading at amounts higher than that could result in mould
contamination of the cocoa. Plans for these solar driers are given at the end of this document. Illustration 22: A solar drier recommended for the Mekong Delta region of
Vietnam with cocoa on the drying bed.

Illustration 24: Cut test chart for determining cocoa bean quality Defective beans include slaty, insect damaged, flat beans, over-fermented and mouldy beans. According to
international standards mouldy beans should not exceed 3%; slaty beans should not exceed 3% and insect
damaged, germinated or flat beans 3% by count. 16
In Vietnam, buyers prefer to purchase cocoa with around 80% of brown beans and usually pay a premium for
this type. Adherence to the methods of fermentation advised should result in cocoa with this percentage of
fully brown beans.

CONSTRUCTION OF SOLAR DRIERS AND FERMENTATION BOXES

Solar driers should be constructed on a concrete base; 6.5M in length, 1.5M in width and 100mm thick. The
length of the concrete base should run in a North – South direction so that the two wings are heated evenly by
the sun travelling East – West.

A diagrammatic representation of a solar drier placed on a concrete base and the dimensions for a 100kg wet
bean capacity (2 sq M drying bed) is given in diagram 1.

The polycarbonate sheets were obtained from John Patterson of the company Suntuf (email:
; telephone (61-7) 324 51301), or from P.T. Impack Pramata Industri, (email:
; telephone: (6221) 653 11045). The polycarbonate sheets SolarTuff of
P.T. Impack Pramata Industri are now available in Vietnam.
The following instructions should be followed when erecting a solar drier.
1. The sheet is marked with a “THIS WAY UP” sticker. The sheet must be installed with this sticker
facing up to the sun. Do not remove these stickers until construction is complete. If the sheeting is to