Hindawi

Journal of Food Quality

Volume 2022, Article ID 9184374, 8 pages
https://doi.org/10.1155/2022/9184374

Research Article
Coffee Drying and Processing Method Influence Quality of Arabica
Coffee Varieties (Coffee arabica L.) at Gomma I and Limmu Kossa,
Southwest Ethiopia

Elfinesh Firdissa ,1,2 Ali Mohammed,1 Gezahegn Berecha,1 and Weyessa Garedew1
1
Jimma University, College of Agriculture and Veterinary Medicine, Department of Horticulture and Plant Sciences,
Jimma, Ethiopia
2
Wollega University, Department of Horticulture, Shambu, Ethiopia

Correspondence should be addressed to Elfinesh Firdissa; qananii2013@gmail.com

Received 15 September 2021; Revised 9 March 2022; Accepted 25 March 2022; Published 6 April 2022

Academic Editor: Flora V. Romeo

Copyright © 2022 Elfinesh Firdissa et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
Solar tunnel drying and semiwash processing methods are popular among coffee growers in southwestern Ethiopia. However, the
effect of these processing methods on coffee quality has not been studied in detail. The objective of this study was to evaluate the
effect of processing and drying methods on the quality of coffee varieties at Gomma-I and Limmu Kossa areas in the 2016/2017
growing season. Two processing methods (fully washed and semiwashed) and three drying methods (solar tunnel, artificial, and
natural sun) were compared using three coffee varieties (741, 7440, and 74110) to test their effect on coffee quality. Coffee beans
processed by semiwash method and dried by solar tunnel produced nondefective (primary and secondary) coffee beans compared
with others at both locations. Similarly, coffee beans processed by semiwashed method recorded the highest mean value for shape
and make and body than wet processing method. Best coffee bean color, greenish color, was produced from coffee beans processed
by the fully washed processing method. All coffee varieties processed by semiwashed method produced medium pointed acidity,
the second most acceptable grade value for coffee quality for all drying methods. Coffee beans processed by the fully washed
method produced more flavor than semiwash processing method. Coffee beans dried by sun and solar tunnel drying methods also
produced better flavor than artificial drier. In general, all coffee varieties processed by semiwash method and dried by natural sun
and solar tunnel method produced higher preliminary total quality and total specialty coffee value, graded under specialty grade
Q1. Hence, coffee growers in the study area can use semiwash processing method and solar tunnel dryer as an alternative/
complementary processing method since they produce better or equivalent quality product with full wash and natural sun
drying method.

1. Introduction produces a range of distinctive Arabica coffee and has

considerable potential to sell a large number of specialty
Coffee is one of the most important cash crops for many coffee beans. However, many factors influence the coffee
countries across the world. The crop is produced in more quality and hence its export potentials. Many studies in-
than 80 countries [1], and for many developing countries, it dicated that coffee physical and cup quality is largely de-
is the most important source of foreign currency [2]. In the termined by genetic factor, growing condition, processing
2020/2021 production year, in Ethiopia, the areas covered by methods, and the techniques used for drying [5–9].
coffee production are estimated to be about 856,591.99 ha In Ethiopia, coffee processing is carried out by dry and
with a production of about 584,789.57 tons of green coffee wash (wet) processing methods. Washed coffee processing
[3]. Ethiopia possesses a diverse genetic base of Arabica method has been mainly practiced by commercial coffee
coffee with considerable heterogeneity [4]. The country farms [10]. In washed coffee processing method, both
2 Journal of Food Quality

natural fermentation (i.e., full washing method) and 2. Materials and Methods
demucilager (i.e. semiwashing method) are being used to
degrade and remove the slimy mucilage compound from the 2.1. Description of the Study Area. The experiment was
bean. In the case of semiwash, the fermentation step is carried out at Limmu Horizon coffee plantation farms lo-
omitted and the mucilage is removed by a demucilage cated at Gomma I (7°57′N and 36°42′E; elevation of
machine and there is no need for any kind of fermentation 1400–2270 masl) and Limmu Kossa (7°57N′ and 36°53′E;
before drying. This method has been reported as modern elevation of 1600–2000°m.a.s.l) of Jimma Zone, Oromia
and known for its simplicity, high water use efficiency [11], Regional State, southwest Ethiopia. The weathering profile of
reduced coffee weight loss [12], and less time requirement Gomma I is characterized by annual mean temperature and
compared with the full-wash method [13]. Because of such rainfall of 21.7°C and 1600 mm, respectively. Limmu Kossa is
an advantage, the semiwash processing method (i.e. the use characterized by annual rainfall of 1920 mm and annual
of demucilager) is currently being popularized and used by average minimum and maximum air temperatures of 12°C
small-scale coffee producers in Ethiopia. However, little and 27°C, respectively. The area is located in the coffee-based
information has been known about the influence of the farming system of the country.
semiwash method on preliminary quality and specialty
quality of coffee in Ethiopia.
2.2. Experimental Treatment. The experiment consisted of
The drying process is very important for keeping the
two processing methods (fully wash and semiwash) and
quality of coffee [14], as drying reduces the humidity content three drying methods (solar tunnel, artificial, and natural
of the bean and impedes the microbial action that is re- sun) using three improved Arabica coffee varieties (741,
sponsible for spoilage during storage. In Ethiopia, small- 7440, and 74110) at two study locations (Gomma I and
holder coffee producers dry their coffee using the natural Limmu Kossa). The different varieties used in this experi-
sun. This method of drying, however, has many limitations, ment were purposely selected due to their popularity in the
including variability in drying duration, high labor demand, study area; they are being cultivated by most coffee pro-
and dependence on weather conditions. The long rainy ducers because of their resistance to coffee berry disease and
season prevailing in southwest Ethiopia created a big high yielding capacity.
challenge for coffee growers to dry their coffee. The artificial
drying process has a great capacity for drying huge quantities
of coffee in a short amount of time and is not affected by 2.3. Sample Preparation. For the purpose of uniform pro-
weather conditions because it uses fuel or wood as a source cessing, red and ripe coffee cherries were selectively har-
of energy. Artificial drying has been used for a long time, vested from each variety at each study site during the peak
despite the fact that the initial cost of this method is very harvesting period, in the month of November. At each lo-
high, and it also requires additional costs for the firewood cation, a total of 54 samples (3 Varieties X 2 Processing
heat source. Methods X 3 Drying Methods X 3 Replications) were col-
To solve such a problem, large commercial coffee farms lected. For the fully washed coffee processing method, ripe
recently started using solar tunnel drier as an alternative coffee cherries were separately pulped by using a coffee
coffee drying method. Solar tunnel dryers are assumed to pulper machine (Aagaard Pregrader, McKinnon, Brazil).
improve product quality (color, texture, and taste) and re- Immediately after pulping, the parchment coffee was sorted
duce postharvest loss, product contamination by insects, from the pulp and soaked underwater to separate the
microorganisms, and mycotoxin, and drying time up to 50% floaters. Then, the heavier parchment coffee was allowed to
compared to the sun drying method [15]. The principle of ferment in the fermentation tank for 24 hours. After
greenhouse is used in the operation of solar driers, where degrading the slippery mucilage, the parchment coffee was
solar energy is trapped by manifolds that raise the tem- further cleaned through washing and soaked with clean
perature of the air. The use of solar dryer also protects the water for 24 hours. After removing the mucilage, the
coffee beans from adverse weather conditions [14]. The parchment coffee was subjected to predrying or partial sun
reduction of moisture content from 55% to 11% in wet basis drying.
within a span of four days has been reported for parchment For semiwashed coffee, the coffee cherries were intro-
coffee dried by solar dryer in Ethiopia [16]. However, little is duced into a demucilaging machine (Mucilage remover,
known about its effect on coffee quality in Ethiopia. Pinhalense, Brazil) to remove pulp and mucilage. Then, the
The quality of coffee also depends on the genetic makeup parchment coffee was washed with pure water to remove the
of the genotype. Variation of coffee quality among coffee remaining mucilage. After removing the mucilage, the
varieties has been reported by many authors [5, 6, 10]. parchment coffee was washed with clean water and subjected
Therefore, this study was initiated with the hypothesis of to predrying. In both processing methods, the predrying was
semiwash processing and solar tunnel drying method has a performed on raised beds, which reduced the moisture
significant effect on the quality of coffee varieties in Ethiopia. content of the parchment coffee by approximately from 60%
Therefore, the objective of the present study was to evaluate to 30%. After predrying, each sample of parchment coffee
the influence of coffee processing and drying methods on the was subjected to three drying methods (natural sun, solar
preliminary quality and specialty cup quality of coffee va- tunnel, and artificial drier) until the moisture content of
rieties at Limmu Kossa and Gomma I commercial coffee 11.5% was achieved for each drying method at each study
farms, southwest Ethiopia. site.
Journal of Food Quality 3

During the study period, the ambient air temperature in percent of the evaluation [17]. The sum of these cup quality
the study location was 21–23°C, the room temperature for attributes gives total specialty cup quality scores ranging
the solar tunnel drier was 35–40°C, and the artificial dryer from 0 to 100. Hence, those coffee samples that have got
was 90°C. Finally, the sun drying method takes 8 days, the grade 1 (score ≥85 percent) and grade 2 (score in the range of
solar tunnel dryer 4 days, and the artificial drying method 80–84.75) qualify for specialty coffee and are further
takes 30 hours to dry the parchment coffee to 11.5 percent grouped into specialty 1 (Q1) and specialty 2 (Q2), re-
moisture content after predrying. spectively [17].

2.4. Data Collection and Quality Analysis. For quality 2.5. Statistical Analysis. The collected data were checked for
analysis, each coffee sample having 1 kg dried coffee the assumption of analysis of variance (ANOVA) (nor-
parchment was coded and taken to the Ethiopia Commodity mality, homogeneity, and constant variance) before being
Exchange (ECX), Jimma Branch, for physical and cup subjected to the analysis using the SAS computer software
quality analysis. A coffee hulling machine (Coffee huller, version 9.3. The procedure of Proc general linear model was
Pinhalense, Brazil) was used to de-husk the dried coffee employed to determine the significant effect of the factors
parchment with a moisture content of around 11.5 percent. involved on the preliminary and specialty coffee quality
For physical and cup quality analysis, 350-g clean coffee analysis. The collected data from two production areas were
beans were used for each sample. During physical analysis, combined after checking the homogeneity of error variance
each coffee sample was evaluated for their primary and (i.e., error variance difference between the two locations was
secondary defects, shape and make, color, and odor small). Significant differences between treatment means
according to ECX [17] (Table 1) quality analysis procedure. were determined using the least significant difference (LSD)
The primary defects include fully black beans, full sour test at 5% probability level.
beans, fungus-attacked beans, broken beans, insect-dam-
aged beans, pod/husk, and foreign matter, while the sec- 3. Results and Discussion
ondary defects considered include partial black, partial sour,
floater, immature, foxy, under/over dried beans, faded/ 3.1. Primary and Secondary Defects. The primary defect was
starved beans and stinkers, faded/coated beans, and light/ significantly affected by the interaction effect of location with
starved beans [17]. processing methods, drying methods, and varieties. At both
For cup quality analysis, 100 g of coffee sample was locations, less primary defect was recorded from coffee
roasted at 160–200∘C for 8–12 min using a roasting machine varieties processed by the semiwashed method (Table 4).
(4 Barrel Roaster; Probat, Emmerich am Rhein, Germany) Except for the artificial dryer at Gomma I, the coffee drying
adjusted to medium roasting. The roasted beans were tipped methods employed produced less primary defect at both
out into a cooling tray and rapidly cooled by blowing cold air locations (Table 5).
through the beans for 4 min and then ground with a coffee The relatively absence of primary defects may be due
grinding machine (K32SB2; Mahlkonig, Hamburg, Ger- to proper harvesting of red ripe cherries during har-
many). Next, 13.75 g of ground coffee was diluted in 250 mL vesting followed by proper handling during processing
of hot water (93°C) to prepare an infusion. Five cups of steps. However, the little difference observed among the
brewed coffee of each coffee sample were prepared for treatment combination could be associated with the
analysis, and a team of three professional cuppers, who fungus and insect damage observed on coffee beans in the
operate in ECX, tasted and gave a score for each of the five study area. These damages were observed in both loca-
cups. tions during coffee harvesting periods. In addition,
The cup quality was determined on the basis of the level broken beans that resulted during processing and drying
of acidity, body, flavor, and cup cleanness of the brew time might be attributed to the difference. Different
according to the standards of ECX [17] (Table 2). Thus, the studies reported that defects may be occurred during
sum of four cup quality attributes (cup cleanness, acidity, different stages of coffee production such as harvesting,
body, and flavor) accounts for the preliminary cup quality processing, and drying of coffee beans, which results in
score of 60 percent, while the physical analysis (primary, cup quality deterioration [18, 19]. Tolessa [20] reported
secondary, shape and make, color, and odor) accounts 40 that well-harvested and properly processed coffee beans
percent of the score. have no or very few broken beans and are free of foreign
Hence, preliminary total quality scores (physical and cup matters such as sticks, stones, and leaves.
quality), between 0 and 100, were used to grade the coffee The interaction effect between location and drying
beans into different grades according to the standard of ECX method was also significantly influenced the secondary
[14] (Table 3). defects of coffee beans. Similar to primary defect, except
Those coffee samples with grades from l to 2 in the artificial dryer at Gomma I, the coffee drying methods
preliminary assessment (Table 3) were further assessed for employed produced less secondary defect at both loca-
the potential of specialty coffee based on the standards of tions (Table 5). In general, semiwashed processing
ECX [17]. Those samples were further evaluated for their method and solar tunnel drying method produce non-
fragrance, flavor, after taste, acidity, body, uniformity, bal- defective (primary and secondary) coffee beans compared
ance, clean cup, sweetness, and overall, each account for 10 with the other processing and drying methods at both
4 Journal of Food Quality

Table 1: Standard parameters and their respective values used for washed coffee raw (physical) quality evaluation (ECX, 2015).
Raw value (40%)
Shape and make
Defects (20%) Color (5%) Odor 10 (%)
(5%)
Primary (count) (10%) Point (Pts) Secondary (wt) (10%) Pts Quality Pts Quality Pts Quality Pts
1 10 ≤5% 10 Very good 5 Bluish 5 Clean 10
2–5 8 ≤8% 8 Good 4 Grayish 4 F. clean 8
6–10 6 ≤10% 6 F. good 3 Greenish 3 Trace 6
11–15 4 ≤12% 4 Average 2 Coated 2 Light 4
15–20 2 ≤14% 2 Small 1 Faded 1 Moderate 2
>20 1 ≤14% 1 Strong 1

Table 2: Standard parameters and their respective values used for washed coffee cup quality evaluation (ECX, 2015).
Cup quality value (60%)
Cup cleanness (15%) Acidity (15%) Body (15%) Flavor (15%)
Type Point Type Point Type Point Type Point
Clean 15 Pointed 15 Full 15 Good 15
Fairly clean 12 M. pointed 12 M. full 12 Fairly good 12
1 cup defect 9 Medium (M) 9 Medium (M) 9 Average 9
2 cup defect 6 Light 6 Light 6 Fair 6
3 cup defect 3 Lacking 3 Thin 3 Commonish 3
>3 coffee defect 1 Not detected 1 Not detected 1 Not detected 1

Table 3: Grading standards of Ethiopian washed commercial coffee fully washed processing method, while grayish color coffee
(ECX, 2015). beans were obtained from coffee beans processed by sem-
Grade Total value (raw value + cup quality value) iwashed method (Table 6). This variation can be attributed to
Grade 1 ≥85
the different quantities of water applied in fully washed and
Grade 2 75–84 semiwashed processing methods. The best coffee bean color
Grade 3 63–74 can be obtained by removing the mucilage by fermentation
Grade 4 47–62 underwater [10].
Grade 5 31–46
UG (P) 15–30
UG (NP) 15–30 3.4. Body. The body of coffee beans was significantly
influenced by coffee varieties and processing methods
(Table 6). Coffee beans with more body were recorded from
locations. Coffee samples processed by demucilager with variety 741 to 7440, while the lower body was recorded from
soaking produced superior overall standards compared variety 74110. However, all coffee varieties were categorized
with those processed with natural fermentation [10]. under grade value of medium- to full-to-medium mouth
feels [17]. Coffee beans processed by semiwashed method
3.2. Shape and Make. The shape and make of the coffee produced more body than wet processing method. The
beans were significantly influenced by varieties and pro- semiwash processing method produced the medium-full
cessing methods. Higher mean value for shape and make was body, which is the second most acceptable cup quality value
registered for variety 741 (4.47) and 74110 (4.44), while the for coffee bean quality [17]. The three drying methods have
lowest mean value (4.22) was from variety 7440. Similarly, not shown a significant effect on the body of the coffee bean.
coffee beans processed by the semiwashed method produced
a higher mean value (4.50) of shape and make compared
3.5. Acidity. All coffee varieties processed by semiwashed
with the full wash processing method. In both cases,
method produced medium pointed acidity, second most
however, all the varieties and processing methods were
acceptable grade value for coffee quality next to pointed [17],
categorized under good and very good grades for shape and
for all drying methods employed (Table 7). On the other
make with a more uniform appearance (Table 6). Gure et al.
hand, the lowest mean value (9.50, medium grade value) was
[10] also indicated that varieties and processing methods
registered for variety 74110 processed by fully washed
significantly influenced the shape and make of coffee beans.
method and dried by artificial drying method. This result
indicated that relatively more acidity could be obtained for
3.3. Color. The type of coffee processing method used has a coffee varieties processed by the semiwashed method than
significant effect on bean color (Table 6). Greenish color the fully washed method. This difference can be due to the
coffee beans were obtained from coffee beans processed by different steps undertaken; more water use in the fully
Journal of Food Quality 5

Table 4: Interaction effect of location and processing methods on primary defect of coffee beans and preliminary total quality.
Location Processing methods Primary defect Preliminary total quality
Fully washed 9.55b 83.55bc
Gomma I
Semiwashed 9.77ab 84.41ab
Fully washed 9.11c 82.52c
Limmu Kossa
Semiwashed 10.00a 84.74a
LSD (0.05%) 0.39 1.08
CV (%) 6.71 1.86
Mean values followed by the same letter within a column are not significantly different at P � 0.05.

Table 5: Interaction effect of location and drying methods on primary and secondary defect and preliminary total quality of coffee beans.
Location Drying methods Primary defect Secondary defect Preliminary total quality
Sun 9.89a 9.89a 84.44ab
Gomma I Solar tunnel 10.00a 9.67a 85.22a
Artificial 9.11b 8.56b 82.27c
Sun 9.56ab 9.56a 84.11ab
Limmu Kossa Solar tunnel 9.56ab 9.33a 83.33bc
Artificial 9.56ab 9.44a 83.44bc
LSD (0.05%) 0.51 0.59 1.28
CV (%) 6.71 7.18 1.86
Mean values followed by the same letter within a column are not significantly different at P � 0.05

washed processing method might lead to removing the acid locations (Table 5). Particularly, at Gomma I the coffee beans
content of the coffee beans. This finding is in line with the dried by solar tunnel dryer were graded under grade 1. In
previous studies [10] who reported that coffee beans pro- general, all coffee varieties processed by semiwash method
cessed by de-mucilage machine produce high acidity levels. and dried by the natural sun, and solar tunnel produced
Similarly, the study indicated that sun and solar tunnel more total preliminary quality value compared with other
drying methods registered more acidity than artificial drying methods employed (Table 7). Coffee beans processed by the
methods. Solar dryer improves the coffee quality [14, 16]. semiwash method and dried by the natural sun, and the solar
tunnel was graded under grade 1.
3.6. Flavor. The flavor of the coffee beans was significantly
affected by the coffee processing and drying methods
3.8. Total Specialty Cup Quality. Total specialty cup quality
employed. Coffee beans processed by the fully washed method
was significantly influenced by the four-way interactions of
produced more flavor than the semiwash processing method
location, variety, processing, and drying methods (Table 9).
(Table 8). It produced a fairly good flavor, the second most
The highest mean value (85.50) was registered for variety
acceptable grade value in cup quality next to good [17]. Coffee
74110 grown at Limmu Kossa and processed by semiwashed
beans dried by sun and solar tunnel drying methods also
method and dried by sun-drying method, which was cate-
produced better flavor than artificial drying (Table 8). This
gorized under specialty Grade Q1. On the other hand, the
finding is in line with previous studies [10] who reported that
lowest mean value 81.41 was registered for variety 7440
fully washed coffee samples have good flavor cup quality. The
grown at Limmu Kossa and processed by fully washed
present finding supports the study by Musebe et al. [21], who
method and dried by artificial drying method, which was
reported that sun drying could produce high-quality coffee
categorized under specialty grade Q2.
under good ambient conditions. Solar tunnel dryer is also
The findings of the present study indicated the highest
used to reduce spoilage and improve product quality, which
total specialty cup quality for variety 74110 grown at Limmu
could improve the flavor of coffee beans. The solar dryer
Kossa and processed by semiwashed method and dried by
produces clean beans and smell as the coffee beans are not in
sun-drying method. According to the present study, semi-
contact with dust or Earth, and contamination from animal
washed processing method showed an economical and ef-
excrement or other refuse is avoided [16].
fective method for producing the highest total specialty cup
quality compared with the fully washed method. The present
3.7. Preliminary Total Quality. The total preliminary quality study is in line with the work of Gure et al. [10] who reported
of coffee beans was influenced by processing methods. The that coffee samples processed by demucilager with soaking
semiwash processing method produced a higher total pre- showed superior overall standards compared with those
liminary quality value compared with fully washed coffee processed with natural fermentation. Similarly, sun and
beans at both locations (Table 4). Natural sun and solar solar tunnel drying methods showed superior for producing
tunnel drying methods produced better total preliminary the highest total specialty cup quality coffee compared with
quality value compared with artificial drying method at both the artificial drying method. The study’s finding is in
6 Journal of Food Quality

Table 6: The effect of variety and processing methods on the shape and make, color, and body of coffee beans.
Variety Shape and make Color Body
741 4.47a 3.56 11.00a
7440 4.22b 3.31 10.58a
74110 4.44a 3.44 9.75b
LSD (0.05%) 0.21 NS 0.47
CV (%) 10.48 13.62 11.85
Processing methods
Fully washed 4.26b 3.66a 9.89b
Semiwashed 4.50a 3.20b 11.00a
LSD (0.05%) 0.18 0.18 0.47
CV (%) 10.48 13.62 13.62
Mean values followed by the same letter within a column are not significantly different at P � 0.05.

Table 7: The interaction effect of variety, processing, and drying methods on acidity and preliminary total quality.
Coffee variety Processing method Drying method Acidity Preliminary total quality
Sun 10.00cd 83.50bcde
Wet processing Solar tunnel 11.50ab 83.33cde
Artificial 11.00abc 82.83cdef
741
Sun 12.00a 86.67a
Semiwashing Solar tunnel 12.00a 85.67ab
Artificial 12.00a 83.33cde
Sun 10.00cd 82.33ef
Wet processing Solar tunnel 10.00cd 84.00bcde
Artificial 12.00a 82.50def
7440
Sun 12.00a 85.00abc
Semiwashing Solar tunnel 12.00a 84.83abd
Artificial 12.00a 84.50abcde
Sun 10.00cd 83.33cde
Wet processing Solar tunnel 10.50bcd 84.67abcd
Artificial 9.50 d 80.83f
74110
Sun 10.50bcd 84.83abc
Semiwashing Solar tunnel 11.50ab 83.17cde
Artificial 12.00a 83.17cde
LSD (0.05%) 1.27 1.27
CV (%) 10.39 1.86
Mean values followed by the same letter with in a column are not significantly different at P � 0.05.

Table 8: The influence of processing and drying methods on flavor of coffee beans.
Processing methods Flavor
Fully washed 11.17a
Semiwashed 9.22b
LSD (0.05%) 0.40
CV (%) 10.28
Drying methods
Sun 10.50a
Solar tunnel 10.25ab
Artificial 9.83b
LSD (0.05%) 0.49
CV (%) 10.28
Mean values followed by the same letter within a column are not significantly different at P � 0.05.
Journal of Food Quality 7

Table 9: The interactive effect of location, variety, processing, and Conflicts of Interest
drying methods on total specialty coffee cup quality.
No potential conflicts of interest are reported by the
Location
Processing Drying author(s).
Variety Limmu
methods methods Gomma I
Kossa
Sun 85.00ab 84.83abcd Acknowledgments
Fully washed Solar tunnel 83.66efgh 83.58efgh
Artificial 82.91hijk 82.83hijk Special gratitude goes to Limmu Horizon coffee plantation
741 PLC for allowing us to conduct the experiment in their coffee
Sun 84.00cdef 84.75abcd
Semiwashed Solar tunnel 83.66efgh 84.25bcde processing plants and providing coffee samples for quality
Artificial 82.08kl 83.58efgh analysis. The authors would also like to thank Ethiopian
Sun 83.41efgh 83.25fghij Commodity Exchange (ECX), Jimma branch office, for
Fully washed Solar tunnel 83.50efghi 82.16kl giving permission for making coffee quality analysis and all
Artificial 82.33jkl 81.41l panelists involved in coffee cupping. This work was financed
7440
Sun 83.50efghi 83.50efghi by Jimma University College of Agriculture and Veterinary
Semiwashed Solar tunnel 83.91defg 82.91hijk Medicine.
Artificial 82.33jkl 82.83hijk
Sun 84.75abcd 82.58ijk
Fully washed Solar tunnel 84.75abcd 83.58efgh References
Artificial 82.25kl 83.41efghi
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