Parchment Coffee Research Articles

Improving the drying performance of parchment coffee due to the newly redesigned drying chamber

AbstractThe Colombian coffee growers face many complications when using traditional open‐sun drying techniques such as post‐harvest process delays or incomplete grain dryness because of climate conditions. Therefore, local workshops began fabricating low‐capacity dryers simulating the industrial equipment working principles. One of the most commercialized units is a triple tray rectangular‐shaped dryer with a 31.25 kg capacity of dry parchment coffee per batch, providing the issue with an acceptable solution. However, it was redesigned into a circular shape holding a lower grain bed thickness and a vertical air inlet with a diffusive tray. Both units were simulated using the Thompson and the Michigan State University grain drying mathematical models to obtain their theoretical drying time. Then, a computational fluid dynamics simulation was conducted, attaining the unit's drying air behavior, the circular dryer exhibited notable drying times reduction and even air distribution, optimizing the dryer's performance, representing a benefit for the coffee‐growing farmers.Practical ApplicationsA cylindrical arranged coffee dryer with a vertical air inlet reduces the drying time of the grain, allowing a better rentability of the grower and improves the air distribution inside the equipment, meaning that the moisture removal will occur uniformly, safeguarding that the product's final moisture content meets the required conditions for safe storage.

Physical and Mechanical Properties of Coffee Cherries and Beans in Africa: Review and the State of Arts

Coffee is an important source of income for African smallholder farmers. The world is predominated by three coffee varieties, namely Arabica, Robusta, and Liberica originated in the African countries. However, the low coffee quality attributes can affect the coffee beans' price due to the improper post-harvesting processes. Therefore, this work is aimed to review the physical and mechanical properties of the African coffee cherries and beans on the country-wise level, and review the methods used to measure quality parameters and compare the key coffee quality parameters. This work was qualitatively conducted using secondary data on African Arabica and Robusta coffee from journals, conference proceedings, and reports. Methods used for determining the coffee beans' properties were explored country wise. The coffee attributes of the two coffee varieties were compared through statistical analysis using ANOVA. The review found that the coffee quality depends on geographical characteristics, agronomic factors, and post-harvesting processes. The coffee cherries de-pulping process is linked to the coffee quality to avoid the damage of parchment coffee beans based particularly on the size and shape of coffee cherries and beans. The analysed quality parameters showed that the Ethiopian Arabica coffee beans were larger than the Ghanaian Robusta coffee beans. While the size of Robusta coffee in Eastern African countries, particularly Uganda, is bigger than those in Western countries, especially Ghana. Therefore, the information on the coffee quality attributes can help to improve the performance parameters of the coffee de-pulping machine and enhance the price of African coffee.

Estimation of the ecological foottprint in the production of parchment coffee. Case of the coffee growers of the agricultural coffee cooperative La Prosperidad de Chirinos

Estimation of the ecological foottprint in the production of parchment coffee. Case of the coffee growers of the agricultural coffee cooperative La Prosperidad de Chirinos

Physiological behaviour and nutritional status of coffee (Coffea arabica L. var. Castillo) trees in response to biochar application

AbstractApplying coffee pulp biochar (BC) can be a complementary practice to the application of chemical fertilizers (CF) of crops; however, little evidence of its combined effects on coffee cultivation has been reported. A field trial was carried out during two evaluation years (2019 and 2020) to analyse the effect of the application of different BC doses (0, 4, 8 and 16 t/ha) in combination with four levels of fertilization (0, 33, 66 and 100% of the nutritional requirements) on physiological responses of 3-year-old coffee (Coffea arabica L. var. Castillo) trees. The results indicated that trees with 0 t/ha BC and 0% CF showed the lowest values in all the physiological variables studied (gs = 269.9 and 126.8 mmol/m2/s; Chl = 61.7 and 54.7 At-leaf readings; yield = 0.21 and 0.22 kg of dry parchment coffee (DPC)/tree for 2019 and 2020, respectively). Coffee trees treated with 8 t/ha BC and CF levels of 100% registered the highest results in gs (424.9 and 366.9 mmol/m2/s), Chl (71.1 and 69.8 At-leaf readings), yield (0.41 and 0.57 kg of DPC/tree) in 2019 and 2020, respectively. In conclusion, the application of BC from coffee pulp, especially at a dose of 8 t/ha, generates a positive effect on yield, gs, leaf nutrient concentration and Chl of coffee trees. The use of BC can be an alternative to complement the mineral nutrition of commercial coffee crops to help reduce the application of CF.

Small-scale Demucilager Machine for Arabica Coffee (Coffea arabica)

Natural fermentation is time- and water-consuming, laborious, and causes weight loss in the coffee beans. It is the conventional method to remove coffee mucilage in the Philippines that can take up to 48 hours. This study aimed to develop a small-scale demucilager machine and evaluate its demucilaging capacity, demucilaging efficiency, product recovery, damaged parchment coffee, and electrical power consumption. It also aimed to compare the use of the demucilaging machine and the natural fermentation in terms of processing time, human labor, and water consumption. The developed demucilaging machine is a continuously-fed horizontal machine that separates mucilage from the parchment coffee by abrasion. It consisted of the following components: the hopper, which receives the freshly depupled parchment coffee: the demucilaging cylinders, which separate the mucilage to the parchment coffee: the water supply system that delivers water to the hopper and the demucilaging cylinders: the output chute, that discharges the parchment coffee: the power transmission system, transmit power from the electric motor to the machine: and, the frame, that holds other components in place. Evaluation results showed that the machine has a 37.87 kg/hr capacity, 79.0% demucilaging efficiency, 4.87% parchment coffee damage, 96.96% product recovery, and 41.54 W-hr electrical energy consumption at 1.23m/s peripheral speed and 0o inclination. It also reduced processing time from 12-24 hours using natural fermentation to 2.64 hours using the machine. Human labor was also reduced from 4 in natural fermentation to 2 operators using the machine. Water consumption from natural fermentation to machine use is 0.87-1.60 L/kg to 0.22 L/kg, respectively. Lastly, the use of the machine is economically feasible at a custom rate of 1.75 Php/kg with a break-even weight of 11,517.00 kg/yr. The payback period of the machine is 2.49 years with a benefit-cost ratio of 0.62.

Experimental and computational study of fluidized-microwave drying process of shrinking parchment coffee and determination of quality attributes

Abstract This work presents the fluidized bed drying process combined with microwaves applied to Parchment coffee. In order to study different parameters that affect the quality of the grains, a mathematical model that describes energy and mass transfer during the drying process is presented and solved using Finite Elements Method (FEM) through COMSOL Multiphysics software. The model also considered the shrinkage of the grains due to water removal. Experiments were carried out in experimental prototype equipment obtaining the drying curves, which were utilized to validate the mathematical model. To study the impact of the operating conditions on the quality of the processed coffee, total polyphenolic content and antioxidant capacity were determined by Folin-Ciocalteau and free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods, respectively. Finally, nutritional parameters were related to operating conditions by the polynomial regression and desirability function methodology. Optimal operating conditions (1.4 m/s and 500 W) were found, which provides a product of excellent final quality.

Biochemical methane potential of agro-wastes as a renewable source alternative for electrical energy production in Cuba

The present Cuban economic model focuses on renewable sources of energy production, according to sustainable development strategies for 2030. However, the strategies do not consider biogas (or methane) due to, among other reasons, a lack of knowledge of its actual potential. Following the methodology of the batch anaerobic digestion process, the study shows the biomethane potential contained in the most critical agricultural solid wastesgenerated in Cuba, i.e., rice straw, cane straw, corn straw, bean straw, banana straw (leaves), coffee husk, and parchment coffee. Biochemical Methane Potential (BMP) was assayed by lab-scale (585 ml) batch reactors, using the pig manure anaerobic sludge as inoculum under mesophilic conditions (35 ± 2 °C). Physicochemical parameters (total volatile solids, pH, alkalinity, volatile fatty acid concentration, and alkalinity ratio) were determined for processstability, quantifying the biogas production daily. Subsequently, the BMP was calculated for all substrates. The results showed that corn straw (0.42 l CH4 per gram of volatile solids) contained the highest biomethane potential. Stability on all systems was obtained, demonstrating the viability of the inoculum used to start digesters that treat this waste.The total potential methane obtained was 1258 106 m3/year, which is enough to generate 3,750 GWh of power per year—equivalent to 18 % of the total annual electricity generation in the country.

Storage fungi and ochratoxin A associated with arabica coffee bean in postharvest processes in Northern Thailand

Arabica coffee is one of the most popular varieties globally; however, during postharvest and storage, it can be contaminated by fungi which produce mycotoxins such as ochratoxin A (OTA). The goal of this study was to determine fungal contamination and OTA levels of arabica coffee produced from Chiang Rai and Chiang Mai provinces in Northern Thailand. Aspergillus and Penicillium were mainly isolated and evaluated from coffee samples in the postharvest process. Coffee cherries, parchment coffee, and green coffee beans were commonly found contaminated with fungi. Coffee beans were contaminated with Penicillium, Aspergillus section Flavi, Aspergillus section Nigri, and Aspergillus section Circumdati at 1.2–10%. Fungal contamination in parchment coffee was studied using three drying methods. The results showed that coffee dried in a greenhouse had higher fungal contamination than samples dried on concrete ground or on a bamboo table. Whether basic storage packaging of green coffee beans affects fungal contamination was also investigated. Green coffee beans in three packaging types showed similar levels of Penicillium, while of the three packaging types, coffee in a polypropylene woven bag showed significantly less Aspergillus than those in a ramie sack or a plastic mesh bag. Fourteen strains of Aspergillus section Circumdati were isolated from coffee samples and 5 isolates showed green-blue fluorescence under ultraviolet light suggesting a potential of OTA production. The morphology of Aspergillus section Circumdati isolates were studied and five isolates with similar morphological characters were further identified to the species level based on ITS and the β-tubulin gene regions. Sequencing and phylogenetic analysis suggested that four isolates were grouped with A. westerdijkiae and one isolate with A. melleus. Analysis of OTA in parchment coffee, green coffee beans, and roasted coffee was performed using HPLC. The results showed that OTA was detected in only one sample of roasted coffee at 0.39 μg kg−1.

Use of agricultural technology, yields and economic profitability of small-scale producers (Coffea arabica L.)

Objective: The objective of this study was to determine the relationship between use of agricultural technology and levels of crop yield and profitability of coffee farmers (Coffea arabica L.) en Puebal and Oaxaca, Mexico. Design/Methodology/Approach: The field work was carried out in the Mazateca region of Oaxaca and the Cuetzalan region of Puebla, in 2019. The data were gathered by applying a survey, using a statistical sample, with 95% confidence and accuracy of 6% of the average coffee yields. Results: The profitability (BCR) was 0.90, which means that for each invested peso, 0.10 pesos were lost, that is, 10% of the investment. For Puebla farmers, the RBC was 1.0 and for Oaxaca producers, 0.81. The BCR of the producers that sold as parchment coffee was 1.16 for those from Cuetzalan and 1.04 for those from the Mazateca region. The group of producers that have high TUI have a different average yield and profitability than the average of the groups of producers that have medium and low TUI. The explanatory variables of yield and profitability are the TUI, the size of the PU, and human capital. Study Limitations/Implications: This study, in a next stage, could benefit from estimating the rate of technology adoption and the training needs of coffee farmers. Conclusions: Due to the positive effect of TUI and HC on yields and profitability, these can be part of public policy interventions to improve coffee growing.

Sensory quality of parchment coffee subjected to drying at different air temperatures and relative humidities

Coffee quality is influenced by several factors, including the drying conditions. Therefore, this study evaluated the influence of the relative humidity of the drying air on the quality attributes of the coffee beverage. Arabica coffee (Coffea arabica L.) fruits were selectively harvested. The samples were dried in two steps in a fixed-bed dryer at an air speed of 0.33 ms-1. In the first step, drying was performed until the water content was 0.428 g of water g of dry matter-1, without controlling the dew point temperature. The second step was performed until the water content was 0.123 g of water/g of dry matter-1, with dew point temperature control. A total of 11 treatments were tested involving nine combinations of dry bulb temperatures of 35 and 40 °C and dew point temperatures of 2.6, 10.8, 16.2 °C, plus two dryings at 35 and 40 °C dry bulb temperature without dew point temperature control. The samples were evaluated sensorially by three certified specialty coffee tasters. The data were subjected to principal component analysis. In the sensory analysis, the samples received total scores of 83.0 to 85.5 points. The drying conditions significantly influenced the quality of the coffee beverage. Drying at a dry bulb temperature of 40 °C and a dew point temperature of 16.2 °C (25% RH) is indicated for the production of higher quality coffees with a shorter drying time.

Effects of Coffee Form and Distributor Hole Angle on The Fluidization Behavior and Specific Energy Consumption in The Fluidized Bed Machine

The fluidized bed technique was applied to use with the Robusta coffee in this research. fluidization behavior and specific energy consumption were investigated under various coffee forms and distributor hole angles. Moreover, the minimum fluidization velocity (Vmf) was also determined. Experiments are carried out in a sample bed height of 5 cm with ambience air. In this study, two coffee forms (Ripe coffee cherries; RCC and parchment coffee; PC) and three distributor hole angles (45º, 60º and 90º) are examined. The experimental result shown that the fluidization behavior is influenced by coffee form and distributor hole angle. The RCC and distributor hole angle of 60º provided the low pressure drop throughout the superficial air velocity. The low values of Vmf and SEC were also achieved in the RCC and distributor hole angle of 60º.

The effect of drying temperature on cup quality of coffee subjected to mechanical drying

The objective of the work was to study the effect of drying temperature on cup quality of the robusta coffee subjected to mechanical drying in comparison with conventional sun drying. The robusta coffee processed by wet (parchment coffee) and dry (cherry coffee) methods were subjected to drying at different temperature regimes (40 oC, 50 oC and 60 oC) in a rotary mechanical dryer. The results of the study indicated that as the drying temperature increased, the time of drying reduced. Sun drying of parchment coffee took 48 hours (approximately seven days) to attain the desired moisture content of 11-12 per cent, while mechanical drying reduced the drying time to 16 to 24 hours. Similarly, cherry coffee subjected to sun drying took 88 hours (approximately 15 days), while mechanical drying reduced the drying time to 32 to 48 hours. The cup quality rating of coffee dried by different drying methods revealed that sun-dried robusta parchment coffee scored the highest cup rating. As the drying temperature increased, the cup quality ratings decreased. A similar cup quality rating was also observed with cherry coffee. These results indicate a considerable reduction of drying time when coffee beans are dried in a mechanical dryer. However, there is a need to regulate the drying temperature, which otherwise would negatively impact the quality of coffee. The drying temperature should not exceed 40oC for preserving the innate quality of robusta coffee because the high drying rates provoked by high temperatures can cause damage to the coffee quality due to the damage caused to the cell membranes. Overall, mechanical drying is more advantageous to sun drying in-terms of drying hours (indirectly reduces dependency on manpower) and preservation of innate quality of the coffee.

Energy Evaluation of the Mechanical Drying of the Grain of Coffea arabica from Honduras

The aim of this research work was to evaluate the methods of mechanical drying of coffee beans (Coffea arabica) from energy evaluations. The control variables were the drying of the grain and energy was used as the response variable, measured in Tonnes of Oil Equivalent (TEP), Barrels of Oil Equivalent (BEP), and Tonnes of Carbon Dioxide Equivalent (Ton CO2eq). The evaluations on the three methods of mechanical coffee drying indicate that the rotary dryer requires 1.0 TEP equivalent to 1.017 kg CO2eqkg-1 in dry parchment coffee (CPS), however, the vertical drying method requires 1.12 TEP (0.616 kg CO2eqkg-1 in CPS) and the static dryer requires 0.5 TEP (0.33 Kg CO2eqkg-1 in CPS). Furthermore, the biomass energy consumption in the rotary dryer is 12.60 MJkg-1, in the vertical dryer it is 7.46 MJkg-1, and the static dryer is 3.91 MJkg-1. These results indicate that the rotary dryer uses 91.95% of the biomass energy, the vertical dryer uses 90.31%, and the static dryer 90.68%. Concluding that rotary drying has a higher biomass energy consumption and reduces CO2 emissions kg-1 in dry parchment coffee, this method is also preferred by cuppers, as it preserves the sensory qualities of the coffee and contributes to reducing the impact. the environment in the consumption of electrical energy and the reduction of CO2 emissions. However, these predictors need more work to validate reliability.

Design of a separation machine using pneumatic system combined with sieve vibration for removing parchment coffee from Robusta green coffee bean

The hulling process for coffee bean extraction may not effectively release the bean from parchment. This might negatively affect the aroma or taste of coffee in the coffee beans roasting process. Consequently, the objectives of this work were to design and construct a machine for separating parchment coffee from Robusta green coffee bean using a pneumatic separation system combined with sieve vibration. The performance of the separation machine was investigated under different operating conditions such as air velocity, vibration frequency, and the angle of sieve inclination. The samples were fed into the machine at a feed rate of 20 kg/h. The testing conditions were set at air velocities of 2 to 4 m/s, vibration frequencies of 36 to 40 Hz, and sieve inclination angle of 4° to 8°. The results showed that the purity and separation efficiency of parchment increased with increasing air velocity. Conversely, decreasing vibration frequency and sieve angle increased the purity and separation efficiency. The appropriate conditions for parchment coffee separation from Robusta green coffee bean using a pneumatic-sieve vibration system were 4 m/s air velocity, 36 Hz vibration frequency, and 8° sieve angle with the highest overall effectiveness of 92%.

Drying kinetics of organic parchment coffee beans (Coffea arabica L.) using microwave fluidised bed: Semi-theoretical modeling

The aim of this study was to model the drying kinetics of microwave and fluidised bed of parchment coffee bean (Coffea arabica L.) using a semi-theoretical approach. A completely randomized design with six treatments: three with microwave drying (MD) and the rest combined with fluidized bed drying (MFBD) was carried out. The drying curves were established until reaching a final moisture content between 10 to 12% w.b. The results indicated that the drying time decreased as the microwave power level increased. When MFBD was used, drying times increased approximately 4-fold compared to MD treatments. The values of effective diffusivity for coffee beans treated with MD and MFBD ranged from 0.913 to1.72×10-9 m2.s-1 and 0.23 to 0.42×10-9 m2.s-1, respectively. Although all the models presented high goodness of fit, the two-term model presented the highest R2 (0.9855 – 0.9978) and lowest RMSE (0.0128-0.0285). In general, all models adequately fitted the experimental data so they can be used to predict the drying kinetics, therefore they could be very useful in equipment design and optimization of the coffee drying process.

Effect of coffee cherry maturity on the performance of the drying process of the bean: Sorption isotherms and dielectric spectroscopy

The study of the dynamic sorption isotherms of parchment coffee revealed that the maturity stage has an effect on the water availability of the bean, and that such dependence might affect the bean drying. The cultivar had an impact on the dispersion at high water activity values (aw > 0.8); hence, depicting dissimilar conditions before the drying is actually performed. The Guggenheim-Anderson-de Boer (GAB) sorption model revealed that stages 2, 3 and 7 present higher monolayer moisture content (Xm), K values close to one for all stages indicated a multilayer behaviour close to free water mobility and low C values for stages 2 and 7 represented a stronger water binding to the monolayer for these stages. Under static conditions and the drying conditions defined according to the moisture content of the beans, the unripe stages depicted an accelerated water activity decay that might promote stalling after roasting due to low values of the attribute (aw < 0.4). In a second phase of the study, the dielectric spectroscopy technique was used to evaluate the effect of the maturity and the drying category, and the response depended on the drying category rather than on the maturity stage except for the drying category with the higher moisture content range. The dielectric constant was utilized to predict both the moisture content and the water activity of the beans. The kernel-based ridge method with radial basis function for the moisture content and sigmoid function for the water activity model had good performance (R2: 0.82–0.88). A feature selection model based on a pipelined framework to include the whole spectra selected the 0.3 GHz to 0.9 GHz range as the optimal estimator, which was consistent with the performance of the single frequency models at 0.3 GHz. Although the errors were lower for the feature selection model, the single frequency is preferable as it has minimal complexity. As a non-linear dependence was evidenced, the machine learning strategies were necessary to respond to this condition. Consequently, the technology could be considered for the assessment of the water features of the bean during coffee drying or the storage of green coffee.

Fungal Diversity and Evaluation of Ochratoxin A Content of Coffee from Three Cameroonian Regions

The present study had the objective to assess the ochratoxin A content of coffee through chromatographic analysis and design a method using PCR-DGGE to analyze at the same moment the totality of fungal flora present in the coffee samples in order to determine their geographic origin. 96 samples of coffee were collected from the west region (Bafoussam and Dschang), centre region (Bafia), and east region (Batouri) of Cameroon during two years (2017 and 2018). Two treatments (dry and wet routes) were evaluated at three different steps of coffee processing (parchment coffee, green coffee, and husk coffee). The characterization of the fungal profile was done with PCR-DGGE and sequencing. The levels of OTA were assessed using HPLC analysis. The results indicated that the toxinogenic mycoflora associated with coffee beans was mainly Aspergillus niger, A. carbonarius, and A. ochraceus. PCR-DGGE data revealed that each sampling site is characterized by a specific fungal profile. Despite the influence of the treatment on the fungal population of coffee, bands common to samples coming from the same site were observed. These bands could therefore constitute potential biological markers to trace back to the origin of coffee. OTA was detected in most of the coffee samples analyzed and only few samples contented OTA at levels higher than the maximum tolerable limit for food intended for human consumption. The OTA content of coffee was significantly influenced by the sampling step and the sampling period.

The Diverging Understandings of Quality by Coffee Chain Actors—Insights from Colombian Producers and Austrian Roasters

This paper addresses the understandings of quality recognized by diverse actors along the coffee chain with focus on specialty coffee producers. In the specialty coffee niche, the assessment of (physical) quality acts as a coordination device among chain actors that enables the identification of divergences on how quality is practiced. This paper aims to uncover how quality attributes (e.g., physical, symbolic) are understood (perceived) by value chain actors and are interwoven with quality conventions (e.g., market, green). Explorative interviews were carried out with Colombian producers located in selected coffee regions. A cupping exercise (tasting of coffee) was organized with producers. Afterwards, another informal cupping was done with roasters in Vienna, Austria. By coupling the concepts of quality attributes and conventions, the paper proposes a theoretical framework that connects quality attributes, conventions and the links to value addition (i.e., from parchment coffee to roasted coffee). Results show that the understandings of quality produce risky battles and ruptures among producers to follow certain conventions. The divergences, risky battles and ruptures in the understandings of quality acknowledged by producers are not only based on “roaster-driven” quality definitions penetrating the producers’ community, or the (individual) knowledge gained by producers, but also on the regulatory framework pursued by producers in a country with a strong coffee federation aiming to legitimize and safeguard the product’s reputation. To what extent is sound experimentation allowed, and direct exchange and interaction between producers, buyers and roasters desirable? Specialty coffee represents a differentiation alternative for small producers located in remote rural areas. Therefore, a transparent and inclusive dialogue between chain actors is required to reduce the divergences in the understandings of quality to balance the value appropriation along the chain.

Spatializing the Coffee Yield Model SAFERNAC with Soil Fertility Data Across Tanzania

The aim of this work was to explore the behavior and usability of the new model SAFERNAC over coffee growing areas throughout Tanzania. Soil fertility data from 1,131 georeferenced points in three zones were fed into the model under four distinct approaches – baseline (no input), organic (manure), inorganic (NPK) and combination of manure and mineral fertilizer. The simulated yields were descriptively compared per zone. They were loaded into QGIS 3.2, interpolated using the Inverse Distance Weighting (IDW) algorithm and the resultant raster maps clipped on basis of digitized boundary shapefiles. Baseline yields were effectively computed from 99.2% of the surveyed sites. The model showed high sensitivity to pH, which has a greater influence on P than N or K. Calculated yields decreased in the order Zone 2 &gt; Zone 1 &gt; Zone 3. The difference in yield between NPK 160:80:80 alone and a combination of NPK 80:40:40 (half dose) plus 5 tons manure was neither quantitatively nor spatially significant. SAFERNAC has proved its usability across the Tanzanian coffee soils, in simulating yield of parchment coffee. The combination approach (organic materials and mineral fertilizers) is most appropriate, as it can reduce the fertilizer cost by about 50% without seriously compromising the expected yields.

Cinética de secagem de café natural e descascado a baixa temperatura e umidade relativa com emprego de uma bomba de calor

Objetivou-se com este trabalho avaliar a cinética de secagem dos grãos de café natural e descascado e ajustar modelos matemáticos aos dados experimentais empregando um protótipo de bomba de calor. A metodologia científica utilizada neste experimento foi uma pesquisa a nível de laboratório empregando o método quantitativo. Os grãos de café foram submetidos a pré-secagem em terreiro suspenso e quando atingiram os teores médios de água inicial de 35,20 e 44,87% (base úmida), para o café natural e descascado, respectivamente, foram encaminhados para secagem no protótipo de sistema de secagem com bomba de calor. A secagem foi conduzida em camada fixa, utilizando 900 g de grãos de café natural e 700 g de café descascado. Submeteu-se a secagem em quatro condições de temperatura de bulbo seco, temperatura de ponto de orvalho e umidade relativa, em delineamento inteiramente casualizado, em três repetições. A partir da determinação da razão de umidade foram ajustados diferentes modelos matemáticos para a descrição da cinética de secagem dos grãos de café. O tempo de secagem do café natural e descascado utilizando o sistema de bomba de calor pode ser considerado baixo para todas as condições de secagem, dado as características morfológicas e do alto teor de água inicial do produto. O modelo de Midilli descreveu satisfatoriamente a cinética de secagem do café natural e descascado em baixa temperatura, utilizando o sistema de bomba de calor. A taxa de secagem é maior para as maiores temperaturas apenas na fase inicial do processo.