SOLAR DRYINGSOLUTIONSFOR CACAO AND COFFEESMALLHOLDER FARMERSIN TABANAN, BALITABLE OF CONTENTS
About the report

3

Executive summary

4

Commodity overview

6

Experiment design

8

Methodology

9

Solar drying solution

12

Cacao

14

Coffee21

Next steps

29

Biji kakao setelah melalui proses fermentasi

ABOUT THE REPORT
Kopernik, with support from the Climate and Land Use Alliance(CLUA), together with smallholder farmers, conducted anexperiment to find efficient methods to dry cacao and coffee
beans in Tabanan, Bali. The report outlines the experiment
process, and presents the findings from the use of a solar dryer
to dry the two commodities. Recommended next steps areprovided, which focus on increasing farmer capacity during thepost-harvest process.
As a key component of the post-harvest process for cacao andcoffee, drying is difficult for farmers, with unpredictable weather
patterns presenting a particular challenge. This issue requires
attention and is critical to address, as it affects farmer incomes
if the drying process is unsuccessful, farmers will be unable to sell
their product. As part of this initiative, we conducted an experimentto identify an effective drying solution by developing a low-costsolar dryer to help farmers to dry their commodities.
The results of the experiment can provide a useful reference forthose who are active in the cacao and coffee sector, as well as
development actors supporting smallholder cacao and coffee
farmers.

3

EXECUTIVE SUMMARY
Smallholders in Tabanan face difficulties in drying cacao and coffee beans due to unpredictable weather patterns.
A simple low-cost technology is required to protect the beans from rain and other contaminants. We conducted
an experiment with a solar dryer, using the following process:
TECHNOLOGY DESIGNDRYINGDATA COLLECTION

DISSEMINATION• Design of the solar dryer.
• Use of locally available
materials to develop the dryer.
• Build the dryer together with
farmers.

Two methods of drying:
Solar dryer• Beans are placed inside thedryer.
Floor drying• Beans are placed on a
tarpaulin and dried on the
ground. This is the typicallyused method by farmers.

• Collect data on dryer
performance, effectivenessand efficiency.
• Measure the quality of thedried beans.

• Conduct a dissemination
event to share findings andlessons from the experimentwith farmers, local
government officials andbusiness actors.

RESULT
NEXT STEPS

4

The solar dryer protected the beans from rain, and reduced farmers’ active work time.
The dissemination event resulted in interest from the local government to replicate thetechnology with funding from the village fund mechanism (dana desa). Kopernik will continue
to provide support by providing guidance on the construction and use of the dryer.

PROJECT LOCATION:
Sanda village, Tabanan,
Bali
PERIOD:Aug – Oct 2020

5

COMMODITY OVERVIEWThis experiment focused on cacao and coffee, which are two of the top commodities produced in tabanan.
CACAO

COFFEE
Yield

833 tons

Yield

228 tons

Land

4,532 haLand

9,585 haSmallholder
farmers

23,375 farmers

Smallholder
farmers

17,387 farmers

Varieties

Sulawesi 1, Sulawesi 2& Local/Lindak

Varieties

RobustaIndonesia is one of the world’s top cacao producers, and in 2019the country exported 380,829 tons of cacao (Bureau of Statistics,
2019). Smallholder farmers are critical to the steady production of
the commodity, and own and manage 99.3% of cacao plantationsin the country.
Bali has 55,903 cacao farmers placing the province amongst the
top 20 producers in Indonesia. Tabanan regency, considered to
be Bali’s center for agricultural produce, has 4,532 ha of cacao
plantations, owned by smallholder farmers.

6

Coffee is one of Indonesia’s largest export commodities. In 2019,
Indonesia exported 279,961 tons of coffee with an economic valueof US$815 million (Bureau of Statistics, 2019), and 96.6% of coffee
plantations are owned by smallholder farmers.
Bali is the tenth largest coffee producing region in Indonesia andhas 71,857 coffee smallholder farmers. Tabanan regency, which is
the largest coffee producing area in the province has
approximately 9,585 ha of coffee plantations.

COMMODITY OVERVIEW
Farmers’ current practice of drying the beans openly on the ground puts the commodity at risk of spoilage due to rain
and other contaminants. We introduced a solar dryer to enable farmers to dry beans efficiently whilst protecting theirbeans.
PROBLEM• The current drying method exposes beans
to rain and other contamination.
• Significant time and effort is required toadminister the open floor drying process.
• No fermentation of cacao beans being
conducted prior to drying.
• Beans are often not dried and sold wet, at alower price.

7

SOLUTION• A solar dryer that enables efficientdrying, and protects beans from rain
and other contaminants.
• A set of fermentation boxes for cacao.

EXPERIMENT• Build the solar dryer together with farmers.
• Ferment cacao beans using fermentation
boxes.
• Dry beans in the solar dryer.
• Compare bean quality of those dried in thesolar dryer, with beans dried using open floor
drying.

EXPERIMENT DESIGN
Together with the farmers, we sorted and fermented cacao beans before placing them in the solar dryer to reach the
moisture level required by the market of 7.5%. For coffee beans, no fermentation was required and the beans weredirectly placed in the solar dryer until they reached a moisture level of 12.5%.
FERMENTATION(CACAO)SORTING+
Beans are sorted to make sureall beans that don’t meet market
requirements are removed.

8

DRYING+
Cacao beans are placed in aset of three-tiered wooden
boxes and fermented for up to
six days, until till they reach atemperature of 44-48 °C.

DRIED BEANS=
Beans are dried in the solar dryer
to reduce moisture content
required by the market; 7.5% forcacao and 12.5% for coffee.

Dried beans are readyto be sold.

METHODOLOGYOur hypothesis was that the solar dryer will dry the beans effectively and protect them from rain and othercontaminants. We tested this hypothesis by comparing the beans dried in the solar dryer, with beans dried using
the open floor drying method.

FERMENTED• Total weight ofwet cacao:
200kg

TREATMENT GROUPCONTROL GROUP

Solar Dryer

Floor Drying
Dryer performance

Cacao:• Beans are fermented for 6
days (44-48 °C).
• Fermented beans are placedin the solar dryer.

• Total weight ofwet coffee
cherries: 80kg

Coffee – honey process*:• Honey processed beans areplaced in the solar dryer.

NON
FERMENTED

Cacao:• Sorted beans are placed in thesolar dryer.

• Total weight ofwet cacao:
200kg• Total weight ofwet coffee
cherries: 600kg

9

INDICATORS MEASURED

Coffee – natural process:• Coffee cherries are placed in
the solar dryer.

100kg
80kg

Cacao:• Beans are fermented for 6
days (to reach 44-48 °C).
• Fermented beans are placedon a tarpaulin on the ground.

Time to dry

100kg
-

Coffee – honey process:• Not applicable for honeyprocessed beans.

Effort required by farmers
Total number of hours spent per day forfarmers to administer the drying process.

Temperature and humidity

Cacao:• Sorted beans are placed on a
tarpaulin on the ground.

Daily indoor/outdoor temperature andhumidity during the drying process.

100kg

100kg

300kg

300kg

Coffee – natural process:• Coffee cherries are placed ona tarpaulin on the ground.

Total number of days taken to reducebean moisture content (cacao 7.5%;
coffee 12.5%).

Bean quality
Quality assessment
Variables include moisture level, color,
mold, slaty and bean count.

*Honey process refers to red beans that are first sorted using a water floating method and then opened with a hulling machine before being placed in the solar dryer. They are not ‘technically’ fermented.

METHODOLOGY
Upon completion of the drying process, we randomized the beans from each group for sampling purposes.
Bean samples from each group were sent to experts, middlemen and artisan buyers to assess the quality of the beans.
Randomized sampling

TREATMENT GROUP
Solar Dryer
The beans are placedon numbered racks
inside the solar dryer.

The number of eachrack/section are written
down on individual piecesof paper.

The pieces of paper withnumbers are placed into a
hat, and five numbers are
selected from the hat to
obtain the five samples thatwill be selected.

The numbers selectedreflect the rack/section
numbers which will be
used for quality testing.

CONTROL GROUP
Floor Drying
Beans are placed ona tarpaulin divided
into 16 numberedsections.

10

The randomly selected
samples from each group aretaken to experts and buyers
for quality testing.

11

SOLAR DRYING SOLUTION
The solar dryer was designed with several innovative features to enable effective and efficient drying of the cacao
and coffee beans.

112Gravel was used for thebase of the dryer to retain
heat.

2

Two exhaust fans were
installed for maintaining
good air circulation.

3

Plastic netting was used forthe body of the drying racks
to avoid rust.

SOLAR DRYING SOLUTION
Farmers can build the low-cost solar dryer using locally available materials.
Materials
ITEM

SIZE

Polycarbonate

11.8 m x 2.1 m x 5 mm

2 rolls

5 cm x 10 cm x 400 cm

3 units

5 cm x 5 cm x 400 cm

20 units

3 cm x 5 cm x 400 cm

17 units

2 cm x 5 cm x 400 cm

32 units

Wood or light steel

2 cm x 3 cm x 400 cm

94 units

Netting

100 m

1 rollIron plate

240 cm x 120 cm x 1.5 cm

3 units

Sand

1 m3

1 m3

Cement

50 kg

5 sacks

Gravel

1 m3

2 m3

Silicon Glue

300 ml3 tubesExhaust fan

12 cm x 12 cm – 1.6 VA

2 units

Wood or light steel

Specification
•
•
•

13

Capacity: ± 300 kg
Energy source: Heat from the sun
Air circulation: Exhaust fans, ventilation holes on thelower and upper sections of the solar dryer

TOTAL

Total cost : ± IDR 17.000.000

EXPERIMENT RESULTS
CACAO

14

CACAO
According to good agricultural practice guidelines, the post-harvest steps for cacao include sorting of beans, fermentation,and drying.
SORTING•••

15

After harvesting, the cacao pods are cut
laterally to extract the wet beans.
High quality wet beans are characterized by
the absence of insects or presence of sprouts.
The sorting process is conducted at this stage
by separating any defect beans and placental
stalks.

FERMENTATION••

Wet cacao beans are placed inside a three-tiered
fermentation box to develop fragrance and flavor.
The fermentation process is conducted for six
days; two days in the upper box, they are thenmoved to the middle box for two days, and finallythe beans are moved to the bottom box for afurther two days. The beans are then moved tothe solar dryer.

DRYING••The drying process reduces the moisture
content of the beans. The required moisture
content for cacao beans is between 5% - 7.5%.
The drying time in the solar dryer typicallytakes between 4 – 7 days, depending on theweather condition and amount of beansplaced on the drying racks.

CACAOThe results of the experiment showed that the solar dryer reduced the time and effort required by farmers during thedrying process by 75%. The beans in the solar dryer took three to five days to reach a moisture level of 7.5% or below.
Effort by farmers

Time to dry

Minutes spent/day; N=2 farmers

Moisture (%); N=4 Randomized samples(%)

120 mins/day

75%

30 mins/day

Floor Drying

16

Solar Dryer

20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3

Above 20%

Non Fermented(Solar Dryer)
Fermented(Solar Dryer)

Target 7.5%
Non Fermented(Floor Drying)
0

1

2

3

Non Fermented(Floor Drying)
4

days
5

CACAOThe solar dryer was able to reach higher temperatures and reduce humidity during the day.
Drying performance
Average temperature oC, N= 6 days

Average humidity %, N=6 days

(OC)

(%)
100

40
Solar Dryer

35

90

30

Avg. Solar Dryer

25
20

80
Avg. Floor Drying

15

Floor Drying

Solar Dryer
Avg. Floor Drying

70

Floor Drying

10

Avg. Solar Dryer

60

5
0
06.00

17

Time
12.00

18.00

21.00

50
06.00

Time
12.00

18.00

21.00

CACAOThe results of the analysis conducted on the bean samples by experts, premium buyers and middlemen indicate that solar
dried fermented beans are preffered and have a higher price in the market.
TREATMENT GROUPCONTROL GROUP

Solar dryer

Floor drying

ExpertPremium
buyer

Middlemen

Expert

7.3

7.2

7.5

7.5

Color

Brown

Brown

Brown

Brown

Mold (%)

0

0

0

0

Slaty (%)

0

0

0

0

Insects (%)

0

0

0

0

Grade

B

B

B

B

Smell/Scent

-

-

-

Price/kg (IDR)~48.000

Honey-~34.000~25.000

Moisture (%)
Max. 7.5%

The grade relates to thequality of cacao trees (eg.
how well the trees aretaken care of, pests – notthe post-harvest process).
18

Fermented

Non Fermented

Middlemen

ExpertPremium
buyer

Middlemen

Expert

7.5

7.1

7.3

7.6

6.9

Purple

Brown

Brown

Brown

Brown

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

A

A

A

A

C

-

-

Honey & citrus ---~25.000

Premiumbuyer~30.000< 48.000~34.000

Premium
buyer

Middlemen

7.5
Does not accept non-fermented beans

Non Fermented

Does not accept non-fermented beans

Fermented

Purple000A~30.000

Bean count based on the size of bean

Acceptable abnormal beans

Color of bean indicator

Grade

Bean condition

Max.

Color

Remarks

Total beans/100g

AA

< 85

Mold

4%

Black

Very badA

86 - 100

Purple3%

PurpleBad

B

101 - 110

Insects

1%

Partly Brown

Good

C

>110

Slaty

2%

Brown

Very GoodCACAO
Summary of the key factors: among the four experimentation groups, solar dried fermented beans showed good results
where it required less effort by farmers during the drying process and can be sold at a higher price.
Time to dry

EffortMoisture content

Price

Fermented

✓✓

✓✓✓

✓✓

✓✓✓

10

Non fermented

✓✓✓

✓✓✓

✓✓

✓

9

Fermented

✓✓

✓

✓✓

✓✓✓

9

Non Fermented

✓✓

✓

✓✓

✓

6

Solar Dryer(Treatment Group)

Floor Drying(Control Group)

✓
✓✓
✓✓✓

19

= Poor= Moderate= GoodCACAO
Based on the experiment results, we recommend that farmers sort, ferment, and dry the beans in a solar dryer to meetthe requirments of premium buyers which can result in a higher selling price.
Post harvest processing
Sorting

Fermentation

Solar drying• Sorting good beans (removing defectiveones) early on will affect the overall
quality of the dried beans and lead to ahigher price.

• The fermentation process creates a depthof flavor.
• Premium buyers require well fermented
dried beans to produce high-quality cacao
products.
• A proper fermentation process is best donein a wooden box covered with banana
leaves.

• Drying beans in a solar dryer protects
beans from rain and other contaminants.
• Farmers spend less time and effort toadminister drying process.

20

EXPERIMENT RESULTS
COFFEE

21

COFFEE – NATURAL PROCESSThe number of days to reach the required moisture level of 12.5% was the same for the solar dryer and open floor drying
methods. However, the solar dryer reduced the time and effort required by farmers during the drying process by 75%.
Effort by farmers

Time to dry

Minutes spent; N=2 farmers

Number of days; N=1 each process

120 mins/day

Average moisture
content: 11,65%

Average moisture
content: 11,1%

18 days18 days

Floor Drying

Solar Dryer

75%

30 mins/day

Floor Drying

22

Solar Dryer

COFFEE – NATURAL PROCESS
There was no significant difference in the drying performance between the solar dryer and open floor drying methods forthe natural process coffee beans. This was due to frequent rain and limited sun exposure at the time of the experiment.
Drying performance
Average temperature oC, N=21 days

Average humidity %, N=21 days

40

100
Solar Dryer

35

90

Avg. Solar Dryer

30
25
20

80
Avg. Floor Drying

Solar Dryer
Avg. Solar Dryer

Avg. Floor Drying

70

15
Floor Drying

1060
Floor Drying

5
0
06.00

23

12.00

18.00

21.00

50
06.00

12.00

18.00

21.00

COFFEE – HONEY PROCESS
Honey process beans are highly desired by premium coffee buyers and have a higher value in the market. We conducted
an additional experiment using the honey process combined with the solar dryer. The beans reached the required moisturelevel within 8 days (compared to 21 days for the natural process).
Honey process

De-pulping•

24

Opening of the coffee cherry skinusing a pulping machine prior todrying.

Testing

Solar drying••

The beans are dried with the mucilage layer
still intact.
During the drying process, the mucilage
layer will absorb the air moisture that will
make the beans sticky resembling the
texture of honey.

•

The dried beans were assessed bythree different buyers; Conventionalbuyer, premium buyer, and middlemen.

COFFEE
The results of analysis of bean samples sent to various buyers show that honey processed beans are preffered and priced
higher in the market among conventional and premium buyers. The premium buyer considered the honey processed beans
to be ‘fine robusta’ – a highly valued and sought-after quality of coffee.
TREATMENT GROUPCONTROL GROUP

Solar dryer

Floor drying

Solar dryer

Natural Process

Natural Process

Honey Process

Conventionalbuyer

Premium
buyer

Middlemen

Conventionalbuyer

Premium
buyer

Middlemen

Conventionalbuyer

Premium
buyer

Middlemen

-

-

20

-

-

17.5

10.3

10.3

18

Grade

93

79.75

-

92

80.1

-

93

83

-

Defects (%)

7

10

7

8

10

0

7

0

4

Price/kg (IDR)~25.000

Moisture (%)
Max. 12,5%~28.000 ~19.500~25.000~28.000 ~30.000

Tasting scale

Bean grade

Indicator

Scale

Indicator

Scale

Fragrance

Dry/Break (6-10)

Bitter/Sweet

Low Bitter/Hi Sweet (6-10)

6-10

Mouthfeel

Rough/Smooth (6-10)

FlavorAftertaste

Brackish/Savory (6-10) + Uniform Cups

Salt/Acid

Low Salt/Hi Acid (6-10)

BalanceClean Cups

Comparing 5 cups

~35.000 ~20.000

Conventional buyer and middleman grade thebeans based on defect count and moisture level.

Grade levels of premium buyer applying cupping and tasting process.
Indicator for cupping~28.000

Indicatorbean= Overallquality

Bean grade
Scale

Grade

Total beans/100g

50 (average)

Good

91-10060 (good)

Moderate

81 - 90

Poor

< 80

70 (very good)

6-10

80 (Fine)

Comparing 5 cups

90 (Outstanding)COFFEE
Summary of the key factors: honey processed coffee beans combined with a solar dryer showed good results where
it took less time to dry, required less effort by farmers, and can be sold at a higher price.
Time to dry

EffortMoisture content

Price

Solar Dryer(Treatment Group)

✓✓

✓✓✓

✓✓

✓✓

9

Floor Drying(Control Group)

✓✓

✓

✓✓

✓✓

7

Solar Dryer

✓✓✓

✓✓✓

✓✓✓

✓✓✓

12

Natural Process

Honey Process

✓
✓✓
✓✓✓

26

= Poor= Moderate= GoodCOFFEE
Based on the experiment results, we recommend farmers to first sort their coffee to remove defective cherries,
and diversify their coffee post-harvest process to include the honey process combined with the solar dryer method in orderto reach higher-end market segments with a higher selling price.
Post harvest processing
SortingDryingHoney process+• Sorting good beans (removing
defected ones) using a water
floating process early on will reduce
the risk of beans being bought at alower price.

27• Putting the coffee cherries througha pulper and drying them in the solar
dryer will result in higher quality
beans.

Roasting, cupping and tasting of honey-processedbeans by premium buyer.

28NEXT STEPS
Upon completion of the experiment, we conducted adissemination event to share our findings and lessons learned
from the experiment with farmers, buyers and local government
officials. There was a high level of interest among the attendees
to adopt the solar dryer. Farmers and the head of a farmers’ groupshared their experiences of being unable to dry cacao and coffee
beans during the rainy season, which led to bean spoilage andnegatively impacted their income. From the farmers’ perspective,
the solar dryer would effectively address their drying challenges,
especially during the rainy season.
Moving forward, Kopernik will:• Conduct discussions with other local government officials,
village authorities and farmer groups to introduce thetechnology and improved post-harvest processing and thepotential benefits for farmers. and to determine whether thevillage fund mechanism (Dana Desa) can be utilised to provide
solar drying technology for coffee and cacao farmers in thearea.
• Seek funding to provide continued support to farmers in
Tabanan in the post-harvest process for coffee and cacao andto connect them to markets, especially to premium buyers.

Dissemination event in Desa Sanda, Pupuan, Tabanan, Bali

29

ACKNOWLEDGEMENTS
This report was written by Nanda Riska, Associate Director of
Solutions Lab and Mohamad Dwi Ergianto, Analyst at Solutions
Lab, Kopernik.
We are deeply grateful for the support of Gede Robi Supriyanto forsharing his insights and expertise throughout the experiment,
providing the experiment location, and making linkages to farmers
and government officials. A huge thank you to Edi of Senimancoffee, Pak Peni of Rikolto, Pak Gusti from Kopi Banyuatis, Rolf andOlivia of Ubud Raw Chocolate for spending so much of their timeand providing their in-depth knowledge and expertise as part ofthe experiment process. We thank Bli Wayan for his tireless workand commitment at all stages of the project.
Thank you to the Climate and Land Use Alliance for making thisproject possible through their partnership and funding support.

30

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