Table of ContentsAcknowledgements List of figures List of Illustrations List of plans Harvesting of pods Storage of pods Breaking of pods Fermentation of cocoa Basket fermentations Heap
Trang 1Cocoa Processing Methods for the Production
of High Quality Cocoa in Vietnam
1
Trang 2Table of Contents
Acknowledgements
List of figures
List of Illustrations
List of plans
Harvesting of pods
Storage of pods
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
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
6: The effect of spreading of beans for two hours, prior to placement in boxes, on fermentation temperatures
7: The effect of spreading of beans for two hours, prior to placement in fermentation boxes, on cut test results
8: The effect of soaking of beans in water, for two hours, prior to drying, on brown bean percentages
List of Illustrations
1: Storage of pods in a bamboo cage
2: Pod storage on the floor of a home
3: Cane basket fermentations
4: Plastic basket fermentations
5: Heap fermentation at Nong Lam University Placing of beans on a banana leaf layer
6: Heap fermentation Covering of beans with banana leaves
7: Covering of heap with Hessian bags to keep the heat in
8: Turning of beans by hand
9: Cocoa fermentation boxes in Ben Tre Provence
10: lining of bottom and sides of box with banana leaves
11: Turning of beans by hand in a 50kg fermentation box
12: Partitioned boxes for fermentation of quantities above 100kg wet beans
13: Drainage holes, for excess moisture, in bottom of boxes
14: Cocoa beans spread on wire mesh, for two hours, prior to placement in fermentation boxes
15: Placental material should be removed when breaking pods and during fermentation
16: Cocoa with good brown coloration after fermentation
17: Over-fermented cocoa showing blackish and mould infected cocoa beans
18: Wet beans cut during a fermentation
19: Sun drying of cocoa on mats in Dak Lak Province
20: Traditional sun drying of cocoa in Ben Tre Province
21: A second traditional sun drying method in Ben Tre Province
Trang 322: 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 harvest cocoa regularlyso that pods do not get over-ripe
Over-ripe pods are more likely to get fungal diseases which affect the beans which should then not be used Pods that have fungal diseases should be picked from the trees and placed on the ground away from the cocoa trees or can be buried This will help stop infection of other pods Mice and rats will also eat ripe pods If pods are left too long on trees, the beans will start to germinate and this is undesirable for the general quality and flavour of the cocoa after fermenting and drying
Pods should be harvested every week during the harvest periods and every two weeks when there are not too many pods When pods are cut from the tree, they should be cut with a sharp implement This is to make sure the pod stem is cut off cleanly, without damage to the flower cushion This is the point where the flower grows and then forms a pod Damage to the flower cushion will mean flowers and pods will not grow on it again A different cutting implement should be used to remove diseased pods from the tree If the same knife is used, it
will help the disease to spread
STORAGE OF PODS
After harvesting, pods should be subjected to storage as in illustrations one or two
3
Trang 4Illustration 1: Storage of pods in a bamboo cage Illustration 2: Pod storage on the floor of a home
It is best to store pods in a cool and dry position, under cover from rain, as this will tend to reduce the possibility of fungal contamination Pods, which become infected with fungi, should be discarded Pods are generally stored for seven to nine days or longer When pods are ready to ferment, you will be able to hear and feel the beans moving inside when the pods are shaken This means that enough moisture has been lost from the pod to allow a good fermentation
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
Farmers should obtain a thermometer to measure the temperature on each day of the fermentation The best results are obtained in fermentations where the maximum temperature reached is between 45oC to 50oC As a general rule, the closer to 50oC, that fermentations reach, the better the quality of the dried cocoa is Typical temperatures for the different types of fermentation are presented in figures 5, 6 & 7 For all types of fermentation, beans should be turned on various days Turning means that the beans should be mixed around with a shovel or hands to help get air into the fermenting cocoa and to help make the fermentation even
Trang 5throughout the cocoa When more air gets into the cocoa, as a result of turning, the rate of fermentation will increase and temperatures will go up a few hours later As a general rule, beans need only be turned on day two of the fermentation However, if the rise in temperature is slow, the farmer can increase the number of turns given e.g days three or four, and this will cause the temperature to rise
BASKET FERMENTATIONS
Illustrations 4: Cane basket fermentations Illustration 5: Plastic basket fermentation
In basket fermentations, as in other fermentations, the sides, bottom and top surface are lined with banana leaves This prevents the cocoa from drying out and also acts as insulation to hold in heat Figure five gives temperature measurements of basket fermentations where one set of pods have had seven days storage and another set, seven days storage plus spreading in the sun for two hours
Basket Fermentations
25 30 35 40 45 50
Day of Fermentation
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 45.3oC and this would be considered to be high enough
to also produce a good quality cocoa Basket fermentations are not recommended for quantities of beans less
5
Trang 6than 25kg If a farmer can’t harvest enough cocoa for a 25kg fermentation, the pods should be sold to a processor who has sufficient pods
HEAP FERMENTATIONS
This type of fermentation is the simplest of all and does not require a farmer to have to construct fermentation
boxes This type of fermentation is the most common type conducted in West Africa, although box and basket fermentations are conducted there as well In Vietnam, we are trying to make a cocoa like that of West African cocoa
Illustration 6: Heap fermentation at Nong Lam Illustration 7: Heap fermentation University Placing of beans on a banana leaf layer Covering of beans with the banana leaves
Illustration 8: Covering of heap with Hessian bags Illustration 9: Turning of beans by hand after two days
to help keep the heat in fermentation (note browning of beans on outer layer)
Trang 7Heap Fermentations
25 30 35 40 45 50
Day of Fermentation
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
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Trang 8Illustration 12: Turning of beans by hand Illustration 13: Partitioned boxes for fermentation
in a 50kg fermentation box of quantities above 100kg wet beans
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
25kg 33cm 26cm 30cm
100kg 70cm 43.5 39cm
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
Trang 9larger 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
Day of Fermentation
250kg Box 100kg Box 50kg Box 25kg Box 25kg Heap
Figure 3: Temperatures of fermentations in box capacities of 250kg,
100kg, 50kg, 25kg and a heap fermentation of 25kg
In figure three, a comparison of temperature rises, during fermentation are presented A 25kg heap fermentation is also included Results demonstrate adequate temperature rises in each of the box sizes and the heap fermentation This indicates the suitability of a range of box sizes and heap fermentations
THE EFFECT OF POD STORAGE
Pod storage is convenient for farmers as it can allow them to collect pods over several harvests or sources until they have enough to conduct fermentations In addition to this, results are presented below which demonstrate that fermentations, of beans from stored pods, are more rapid and result in higher brown bean counts than fermentations conducted with beans from fresh pods
Effect of Pod Storage on Fermentation Temperatures
20 25 30 35 40 45 50
Day of Fermentation
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
Trang 10Percentage Brown Beans from Fermentations of Fresh Pods
and Pods stored for seven days
0 10 20 30 40 50 60
Fermentation Time
Fresh Pods Stored Pods
Figure 5: The effect of pod storage and fermentation time on the
percentage of fully brown beans in the cut test
Pod storage also causes a much larger percentage of brown beans to occur in dried cocoa as shown in figure five The number of fully brown beans is also seen to increase with length of fermentation time The fresh beans were allowed to ferment for eight days compared to six days for the stored pods Figure five shows, that even after eight days fermentation, the percentage of brown beans from fresh pods (34%) was much lower than those from stored pods at six days fermentation (49%) As buyers often pay premium prices for cocoa with high levels of brown beans, this is another reason to apply the practice of pod storage
THE EFFECT OF SPREADING OF BEANS AFTER POD BREAKING
After pods have been broken, beans can be spread out on wire mesh or a concrete floor or sheets of plastic This procedure leads to further moisture being lost and an even greater rate of fermentation and temperature rise than that from pod storage alone
Effect of Spreading Beans on Cocoa Fermentation
25 30 35 40 45 50
Day of Fermentation
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