Parchment Coffee Research Articles

La fertilización mineral como complemento a la fertilización con abono orgánico en el cultivo del café.

Con el propósito de evaluar diferentes fuentes potásicas minerales naturales, en mezcla con pulpa de café descompuesta para emplearlas como fertilizantes en el cultivo del café, en la Estación Experimental de Pueblo Bello, ubicada en el municipio de Pueblo Bello, departamento de Cesar, zona cafetera norte de Colombia; se evaluaron dos fuentes de potasio: Sulfato de Potasio (K2SO4) y Sulpomag (K2SO4.2MgSO4), sobre la producción en kilogramos.ha-1 de café pergamino seco; esta producción fue comparada con la obtenida al fertilizar con fertilizantes inorgánicos, con materia orgánica y un testigo sin fertilizar; el café fue establecido a densidades de 3.922, 6.060 y 7.843 plantas/ha en un sistema agroforestal. De los resultados se obtuvo que en la fertilización del café bajo sombrío pueden adoptarse alternativas como la aplicación de materia orgánica en mezcla con fuentes de potasio como el K2SO4.2MgSO4, comercializado como Sulpomag, siempre que se establezcan altas densidades de siembra. El café establecido a densidades inferiores a 6.000 plantas por ha, puede ser fertilizado con fuentes orgánicas o inorgánicas.

Estimación de humedad de café pergamino utilizando un secador solar automatizado, mediante modelos matemáticos en Jaén-Perú

El café es un producto muy consumido a nivel mundial, debido a que posee un poder estimulante y energizante. Además, el proceso de secado es un factor esencial que influye en la calidad final del producto, en este sentido, el objetivo del presente artículo fue estimar la humedad del café pergamino al emplear un secador solar automatizado, mediante modelos matemáticos. Los modelos empleados fueron del tipo regresión lineal múltiple y regresión no lineal, los mismos que fueron determinados con los softwares R y Curve Expert Professional respectivamente. Los datos necesarios para estimar dichos modelos, fueron recolectados en campo durante cinco días, la cual consistió en aplicar el secador solar automatizado en la parcela de un agricultor del centro poblado de las Naranjas, Jaén, Cajamarca, Perú cuya variedad fue Catimor. Se determinaron cinco modelos: Un modelo de regresión lineal múltiple y cuatro modelos no lineales con un coeficiente de correlación mayor que 0,91. Sin embargo, el modelo empleado para describir la radiación solar en Grecia, es el que mejor describe el comportamiento de la humedad del grado de café pergamino en términos del tiempo de secado en el secador solar automatizado empleando los estadístico de bondad de ajuste.

Modeling of fragment formation of parchment coffee beans for rapid heat and mass transfer during fluidization drying

Fluidization drying technique allows fluidized coffee beans to float, resulting in rapid heat and mass transfer, which have been directly associated with an increase in the moisture gradient, creating bean stress. Bean quality is determined by the degree of bean fragmentation caused by drying, an important standard considered in purchasing and selling. We have modeled the drying process to explain the kinetics of bean fragmentation. Drying temperature affected the drying rate and fragmentation of parchment coffee beans. Specific energy consumption varied with the drying rate. Comparing the experimental results for the predicted average moisture content and the predicted bean fragment formation, using a first-order equation, yielded satisfactory results. Modeling enabled the prediction of drying conditions with the lowest possible specific energy consumption, while the final moisture content and bean fragment percentage met commercial standards. Practical applications The advantage of fluidization drying is rapid heat and mass transfer between material and hot air. In spite of this advantage, a rapid reduction of moisture during fluidization may cause stress to the material, resulting in bean fragmentation. Fragmentation is a physical measurement of bean quality after undergoing the drying process; it is one of the standards that is taken into consideration by buyers and sellers. We have developed a model to explain and predict the kinetics of bean fragmentation during the complex drying process. The predictions of our model can be used as guidelines for drying parchment coffee beans by the fluidization technique.

Validación del manejo integrado de Hypothenemus Hampei Ferrari (Coleoptera: Curculionidae) en el Huila, Colombia

El café es el principal producto agrícola de exportación de Colombia, siendo el Huila el mayor proveedor actual. La plaga más limitante es la broca de café. El objetivo de este trabajo fue validar en el campo las estrategias de control usadas en el manejo integrado de la broca. Para esto, se tomó un lote de café en el municipio de Pitalito y se dividió en cuatro parcelas experimentales, correspondiendo a los siguientes métodos de control: M1 Control biológico, M2 Control químico, M3 Control cultural y M4 Testigo manejo implementado por el agricultor. Se evaluó la infestación de broca en el campo y en café pergamino seco, por medio de un muestreo aleatorio simple. Mediante el estimador de razón de los frutos infestados por cada 100 frutos se determinó que el M3 Control cultural fue descriptivamente menor con respecto a los demás métodos de control en el campo. De manera consecuente, el M3 presentó el menor porcentaje de infestación en café pergamino seco. Cuando se implementó el control cultural, se registró en el campo una reducción del 74,55% en el estimador de razón y del 54% en el porcentaje de infestación en café pergamino, con respecto al M4 manejo del agricultor. Esta investigación permite recomendar el control cultural como la mejor estrategia de control de la broca, así mismo, transferir estos resultados a los caficultores de Huila. El control cultural consistió en la cosecha oportuna y en el repase con recolección de frutos del suelo asistidas con dispositivos “canastillas”.

Socioeconomic characterization of coffee farms of the department of Nariño, Colombia

The adoption of technologies generated for the coffee crop, depends to a great degree on factors such as the availability of resources and the producer s scholarship which determines the importance of socioeconomic conditions in the coffee productive system structure. The objective of this investigation was to analyze the main coffee grower s social and economic characteristics in the 220A and 221A Narino Department ecotopes. 159 producers (86 from the ecotype 220A and 73 from the ecotope 221A), were selected randomly based on a sampling frame of 16.767 coffee farms, with the purpose of applying the survey questionnaire. In the statistical analysis, 58 categorical variables were used, they were subjected to a multivariate analysis using the multiple correspondence method and hierarchical classification analysis. The 220A ecotope was characterized by having coffee areas between 1 and 3 hectares, houses with eternit and zinc roofs, cement floors, electric power, aqueduct and sanitary unit. The performance is between 1.001 and 2.000kg.ha1, the cost of production is less than COP1.500,000 (USD44,83); the coffee growers attend training sessions and their family nucleus is made up of 4 - 7 people. In the ecotope 221A the houses with tile roof, cement floors, electricity, aqueduct and sanitary unit predominate; wastewater is disposed of in septic tanks. Good agricultural practices (GAP) aren’t used, the yields are less than 1.500kg.ha-1 (dried parchment coffee) and the cost of production is less than $1.500.000 ha-1. year-1

Caracterización fisicoquímica y microbiológica de aguas mieles del beneficio del café

En el procesamiento del café, sólo se aprovecha el 5 % del producto fresco y se generan residuos como aguas mieles (AM), que pueden llegar hasta 40 L/kg de café pergamino seco y al ser vertidas pueden provocar contaminación de alto impacto ambiental. Consecuentemente, el objetivo fue caracterizar fisicoquímica y microbiológicamente dos muestras de AM (M1, M2) con el fin de evaluar el potencial en la extracción de biocomponentes. Los parámetros medidos a las dos muestras de agua fueron Demanda Química de Oxígeno (DQO), nitrógeno, amonio, cromo, oxígeno disuelto (OD), pH, conductividad, acidez volátil, fósforo, cloruros, sólidos, color y, adicionalmente se cuantificaron mesófilos, coliformes totales y estafilococos. Se identificaron diferencias significativas entre las muestras y un efecto del procesamiento del café, sobre las características evaluadas. M2 mostró mayor concentración de OD, conductividad y cambio de color respecto al control, mientras que M1 tuvo mayor concentración para los demás parámetros evaluados. Cromo y amonio estuvieron por debajo del límite de detección de la prueba empleada, por el contrario, la DQO fue superior a lo reglamentado para aguas domésticas. En el análisis microbiológico, se encontraron mesófilos en ambas muestras, y M2 presentó coliformes y estafilococos. Con lo anterior se evidencia que el método de procesamiento de café afecta los parámetros de calidad de las aguas residuales y por ende se deben implementar metodologías de tratamiento y/o aprovechamiento acordes a las características intrínsecas de cada proceso.

An Agent-Based Model Driven Decision Support System for Reactive Aggregate Production Scheduling in the Green Coffee Supply Chain

The aim of this paper is to contribute to the thread of research regarding the need for logistic systems for planning and scheduling/rescheduling within the agro-industry. To this end, an agent-based model driven decision support system for the agri-food supply chain is presented. Inputs in this research are taken from a case example of a Mexican green coffee supply chain. In this context, the decision support agent serves the purposes of deriving useful knowledge to accomplish (i) the decision regarding the estimation of Cherry coffee yield obtained at the coffee plantation, and the Parchment coffee sample verification decision, using fuzzy logic involving an inference engine with IF-THEN type rules; (ii) the production plan establishment decision, using a decision-making rule approach based upon the coupling of IF-THEN fuzzy inference rules and equation-based representation by means of mixed integer programming with the aim to maximize customer service level; and (iii) the production plan update decision using mathematical equations once the customer service level falls below the expected level. Three scenarios of demand patterns were considered to conduct the experiments: increasing, unimodal and decreasing. We found that the input inventory and output inventory vary similar over time for the unimodal demand pattern, not the case for both the increasing and decreasing demand patterns. For the decreasing demand pattern, ten tardy orders for the initial production schedule, an 88% service level, and nineteen tardy orders from the estimated production results, a 77% service level. This value falls below the expected level. Consequently, the updated aggregate production schedule resulted in ten tardy orders and an 88% service level.

Integrating diversity of smallholder coffee cropping systems in environmental analysis

PurposeCoffee represents an important trade asset internationally. Around 70% of global coffee production is provided by 25 million smallholders farmers. In recent decades, coffee systems have been transformed into more intensified systems of coffee monoculture. The general objectives of this paper are to provide a better picture of the traditional coffee cropping systems and postharvest processes on-farm and to assess the environmental impacts, integrating the diversity of smallholder cropping systems.MethodsA Life Cycle Assessment from cradle to farm gate was performed for three cropping systems representative of Colombian coffee cultivation according to the associated crops and shadow trees: coffee alone (CA), coffee with transition shade (CTS), and coffee with permanent shade (CPS). The system studied includes inputs, agricultural production and postharvest operations using the wet method. The final product of farms is parchment bean coffee at farm gate. The technology used is representative of the average practices of smallholder coffee growers in the region. To address multiple functions of coffee, three functional units (FU) were selected: area by time (ha*year−1 unit area), productivity (ton of parchment coffee) and farmers income (1000 USD$). Seven midpoint categories were selected: climate change, acidification, terrestrial eutrophication, freshwater eutrophication, marine eutrophication, freshwater ecotoxicity, and water resource depletion.Results and discussionWe present the life cycle inventory and impact assessment results from three types of cropping systems CA, CTS and CPS. For all FU, the CPS system has the lowest potential impact, excepted for marine eutrophication. CPS also has the highest coffee yields, however it has also the highest costs. Even if cropping system diversification is only one of multiple factors that influence environmental performance, agroforestry seems to be a promising path to reduce and mitigate environmental impacts by decreasing off-fam contributions (input fabrication).ConclusionsResults show the possibility that diversified cropping systems have an influence when assessing potential environmental impacts of coffee at farm gate and differences found might be influenced by shading in traditional coffee systems. Future work is needed to consider the real potential of CTS cropping system including land use and carbon dynamics. Assessments including social indicators and the rest of the value chain in particular coffee industrial transformation and utilization are also needed since the consumption stages are also a key driver to reduce the environmental footprint of coffee.

Determination of plantain crops associated with coffee environmental impacts on agroecosystems by means of Life Cycle Assessment: case study in the Southwest of Antioquia (Colombia)

Plantain and coffee are basic foodstuff of Colombian family standard basket, constituting important sources in the dynamism of the economy of the country. Given the importance of these products, five environmental impacts: global warming, aquatic eutrophication, terrestrial acidification, aquatic ecotoxicity and use of soil were evaluated in three plantain crops associated with coffee in Antioquia Southwest (Colombia), for this purpose RECIPE 2008 method with a cradle to gate approach was used. Surveys and interviews applied to owners and employees of the farms, and to agents related to the production chains were carried out to obtain primary data, secondary data were taken from Ecoinvent 3.1 database. Consumption of resources and emissions were assigned to a functional unit of 1 kg of plantain and 1 kg of dry parchment coffee. Production systems consisted of four stages: establishment/propagation, production, postharvest and distribution. Plantain system generated less impact than coffee, and the stages that contributed the most to the environmental burden on impact categories in both crops were establishment/propagation and production. This is mainly due to the manufacture and the use of fertilizers.

Thin-layer drying of parchment Arabica coffee by controlling temperature and relative humidity.

This paper presents thin‐layer drying of parchment coffee (Coffea arabica). Thin‐layer drying of parchment coffee was conducted under controlled temperatures (50°C, 60°C, and 70°C) and relative humidities (10%–30%). The temperature of the drying air was important for drying at a high temperature, which results in the rapid removal of moisture and reduced time for drying. Nine thin‐layer drying models (Newton, Page, Henderson and Pabis, logarithmic, two‐term, modified Henderson and Pabis, two‐term exponential, approximation diffusion, and modified‐Midilli) were fitted to the experimental data for parchment coffee. The drying parameters of parchment coffee were related to temperature and relative humidity. The best model was the modified‐Midilli model, which can be used to design the optimal dryer. The effective moisture diffusivity of parchment coffee drying was determined by minimizing the sum of squares of the deviations between the experimental data for the moisture content and the predicted values of thin‐layer drying. The effective moisture diffusivity as a function of the temperature at each relative humidity was expressed by the Arrhenius‐type equation.

Effect of drying and mechanical pre-drying previous to storage in the quality of coffee grain (Coffea arabica L.)

The aim of this study was to evaluate the effect of drying and pre-drying conditions of samples of parchment coffee stored during 6 months under controlled conditions of relative humidity of 70% and temperature of 25°C quantifying the Electrical Conductivity (EC), Potassium Leaching (KL) and Fatty Acidity (FA) of the grain. The coffee drying consisted on combined processes using air temperatures of 50°C and 60°C and two periods of 4 and 8 hours in the mechanical pre-drying and subsequently taken to commercial moisture content under patio drying, and two control treatments consisting of complete mechanical drying and complete solar drying. The results of the tests showed the following values: 6.35 - 16.34 Sm cm-1 / g DM (EC), 2.0 - 4.45ppm / g DM (KL) and 0.76 - 1.57mL KOH / 100g MS (FA), where the statistical analysis shows that there is no effect of the drying type on the studied variables. However, the highest accumulated averages in the storage time were observed for the complete mechanical drying. The values did not show deterioration of the cellular structure attributed to the frame of reference of drying with high temperature or prolonged storage. The tests of Electrical Conductivity (EC) and Fatty Acidity (FA) shows sensitivity to the storage time while the Potassium Leaching (KL) test did not constitute an indicator of grain deterioration attributable to thermomechanical stress or storage time.

Bioclimatic analysis of three buildings for wet processing of coffee in Colombia

Este estudio tuvo como objetivo llevar a cabo una comparación bioclimática de instalaciones de beneficio húmedo en Colombia, con tres tipologías típicas de la zona cafetera colombiana, a través de simulación computacional, específicamente evaluando los efectos del calor y vapor generados por el secado mecánico, y el área de ventilación natural sobre la temperatura y la humedad relativa en estas instalaciones. Se observó el efecto del área de ventilación natural, a mayor área de ventilación natural, menor temperatura y humedad relativa, es decir, se observó que la tipología b se comportó mejor bioclimáticamente que la tipología a. El ambiente interno de la tipología a (tipología escalonada), tuvo un mayor riesgo biológico de proliferación de hongos y bacterias, con una temperatura promedio de 27,5 °C, y una humedad relativa interna promedio de 70,6%. En el tipo c, como su secadora mecánica sobresale del edificio, y expulsa el vapor y el calor producidos en el proceso de secado al ambiente externo, mostró las mejores condiciones bioclimáticas para el café pergamino, con una temperatura promedio de 23,5 °C y una humedad relativa interna promedio del 65,5% la mayor parte del tiempo.

Application of an Energy Efficient Hot Air Recirculation Controlled Closed System Environment for Parchment Coffee Dehydration in Puerto Rico

The high and increasing costs associated with propane gas, diesel and electricity used by mechanical dryers have negatively affected the coffee processors in Puerto Rico. In 1991 the cost to process one hundred pounds of parchment coffee was $14.13, while in 2011 was over $35.00. From all the sectors within the coffee industry in Puerto Rico, the processors are the ones that have experience the largest increases in operational cost, over 145% in the past years, mainly due to post harvesting drying. To address this specific challenge, the Department of Agriculture of Puerto Rico (DAPR) assigned funds to research coffee dehydration energy efficient alternatives that would reduce the costs to the coffee processors of the island. As part of this effort, a hot air recirculation controlled closed-system (HARC2S) was designed and constructed at the University of Puerto Rico at Mayagez. The basic concept of the HARC2S is to condition the hot air that has already passed through the coffee bean mass and direct it back to the mechanical dryer. The hot air conditioning consist in removing part of the moisture from the recirculation air with a heat exchanger that uses water at ambient temperature, to increase the moisture absorbing capacity of the air before it re-enters the mechanical dryer. Experimental results of the HARC2S, under various operational configurations, provided substantial drying energy savings ranging from 12% to 59%. The range variation in energy savings is due to the system operational configurations and possible variations of the parchment coffee bean ripeness state from the various batch experiments. Investing in the development and implementation of this technology will provide not only sustainable operation of the coffee processors facilities, but will also sustain close to 20,000 jobs with potential employment growth representing over a $41 million annual income to the local economy.

Application of an Energy Efficient Hot Air Recirculation Controlled Closed System Environment for Parchment Coffee Dehydration in Puerto Rico

The high and increasing costs associated with propane gas, diesel and electricity used by mechanicaldryers have negatively affected the coffee processors in Puerto Rico. In 1991 the cost to process onehundred pounds of parchment coffee was $14.13, while in 2011 was over $35.00. From all the sectorswithin the coffee industry in Puerto Rico, the processors are the ones that have experience the largestincreases in operational cost, over 145% in the past years, mainly due to post harvesting drying. Toaddress this specific challenge, the Department of Agriculture of Puerto Rico (DAPR) assigned funds toresearch coffee dehydration energy efficient alternatives that would reduce the costs to the coffeeprocessors of the island. As part of this effort, a hot air recirculation controlled closed-system(HARC2S) was designed and constructed at the University of Puerto Rico at Mayagüez. The basicconcept of the HARC2S is to condition the hot air that has already passed through the coffee bean massand direct it back to the mechanical dryer. The hot air conditioning consist in removing part of themoisture from the recirculation air with a heat exchanger that uses water at ambient temperature, toincrease the moisture absorbing capacity of the air before it re-enters the mechanical dryer.Experimental results of the HARC2S, under various operational configurations, provided substantialdrying energy savings ranging from 12% to 59%. The range variation in energy savings is due to thesystem operational configurations and possible variations of the parchment coffee bean ripeness statefrom the various batch experiments. Investing in the development and implementation of thistechnology will provide not only sustainable operation of the coffee processors facilities, but will alsosustain close to 20,000 jobs with potential employment growth representing over a $41 million annualincome to the local economy.

Investigation of Coffee Seed Physical Purity, Seed Health and Effect of Storage Time on Viability

High seed quality is essential for optimum stand establishment in Coffee. As a result, it is necessary to have seed physical, germination percent, physiological and health tests that permit rapid, objective and accurate evaluation of seed quality. This study evaluated the effect of storage time on physical, physiological, germination percent and health quality of seed lots of five coffee varieties obtained from research and commercial company. This test is conducted under ideal laboratory conditions and in the nursery site. After sample collected pure, pea-beery, cracked and shriveled seeds were measured before determining standard germination and vigor. The highest pea berry was recorded at JARC on the variety 75227(18.63), and the lowest was at LCP on the variety 74165 (8.81). In parchment coffee seed, the percentage of physical defects during seed processing affects germination and seedling viability. The standard germination test in the moisten-soft paper continues to be the most common measure of seed quality in coffee. In addition, this test requires more than two weeks before a determination of seed germination was possible. Ideally, seed quality tests efficiently differentiate between poor and good seed lots in a short period. There was high germination percent in the first planting time were recorded after one month storage than other two consecutive storage time. Normal germinated seedling reduced with in increases seed storage time and the incidence of seed/ soil -born pathogenic fungi. The germination test of seeds from laboratory under petri-dish with moist soft paper and at the nursery site also had low vigour and did not produce suitable seedlings for planting evaluated after three month storage. If after one month storage time of coffee seeds germinated more than older seeds (as our study indicates), then seedlings derived from younger may have a competitive advantage over seedlings derived from older one. In the present study, pre-emergence seedling mortality (Rotten) was greater in third month storage than in first month old seeds. This mortality partially accounted for the lower germination percentage in three month old seeds because only seeds that emerged above the soil surface were considered to have germinated is an indication of reduced vigor. In my study, in coffee seeds, seedlings from relatively low stored seeds were generally better able to withstand environmental stress than those from old seeds. Coffee seed sample from two sources stored safely to optimize coffee seedling production at the appropriate time and season with ideal climatic conditions for planting in the field.

Performance of a Big Scale Green House Type Dryer for Coffee Drying Process

Dying is one of important steps in coffee processing to produce good quality. Greenhouse is one of artificial drying alternatives that potential for coffee drying method cause of cleans environmental friendly, renewable energy sources and chippers. Indonesian Coffee and Cocoa Research Institute has developed and testing a big scale greenhouse type dryer for fresh coffee cherries and wet parchment coffee drying process. Greenhouse has 24 m length, 18 m width, also 3 m high of the front side and 2 m high of the rear side. The maximum capacity of greenhouse is 40 tons fresh coffee cherries. Fiber Reinforced Plastic (FRP) used as greenhouse roof that combined with I and C profile of steel. Fresh coffee cherries and wet parchment coffee from Robusta variety use as main materials in this research. The treatment of this research was 30 kg/m2, 60 kg/m2 and 90 kg/m2 for coffee density. String process has done by manual, two times a day in the morning and in the afternoon. As control, fresh coffee cherries and wet parchment coffee has dried by fully sun drying method. The result showed that a big scale greenhouse has heat drying efficiency between 29.9-58.2% depend on type and density of coffee treatments. On the full sunny day, greenhouse has produced maximum drying air temperature up to 52oC. In radiation cumulative level 4-5 kW-jam/m2 per day, 12.9-38.8 tons fresh coffee cherries or wet parchment coffee with 58-64% moisture content can be dried to 12% moisture content for 6 up to 14 days drying process. Slowly drying mechanism can be avoided negative effect to degradation of quality precursor compound. Capacity of the dryer can be raise and fungi can be reduce with application of controllable mechanical stirring in the greenhouse. Keywords: greenhouse, coffee, drying, quality

Carbon footprints and carbon stocks reveal climate-friendly coffee production

Coffee production is impacting the climate by emitting greenhouse gasses. Coffee production is also vulnerable to climate change. As a consequence, the coffee sector is interested in climate-friendly forms of coffee production, but there is no consensus of what exactly this implies. Therefore, we studied two aspects of the climate impact of coffee production: the standing carbon stocks in the production systems and the product carbon footprint, which measures the greenhouse gas emissions per unit weight of coffee produced. We collected data from 116 coffee farms in five Latin American countries, Mexico, Guatemala, Nicaragua, El Salvador, and Colombia, for four coffee production systems: (1) traditional polycultures, (2) commercial polycultures, (3) shaded monocultures, and (4) unshaded monocultures. We found that polycultures have a lower mean carbon footprint, of 6.2–7.3 kg CO2-equivalent kg−1 of parchment coffee, than monocultures, of 9.0–10.8 kg. We also found that traditional polycultures have much higher carbon stocks in the vegetation, of 42.5 Mg per ha, than unshaded monocultures, of 10.5 Mg. We designed a graphic system to classify production systems according to their climate friendliness. We identified several strategies to increase positive and reduce negative climate impacts of coffee production. Strategies include diversification of coffee farms with trees, the use of their wood to substitute for fossil fuel and energy-intensive building materials, the targeted use of fertilizer, and the use of dry or ecological processing methods for coffee instead of the traditional fully washed process.

Economic Optimization of Nutrient Application to Coffee in Northern Tanzania Using SAFERNAC

The aim of this work, as an extension to SAFERNAC model, was to establish economically optimum combinations of N, P and K application to Arabica coffee in the Northern coffee zone of Tanzania. The study was conducted in Hai and Lushoto districts between 2010 and 2012. Prices of nutrient inputs and those of parchment coffee were introduced into the original SAFERNAC model, which was used to obtain yields from a soil of known properties receiving different levels of input N, P and K from both organic and inorganic sources (ISFM). The costs of these were derived from experience in Northern Tanzania, while coffee prices were estimated to range between 1250 and 2500 TZS kg-1. The result was economically optimum N:P:K ratios that give highest net returns and value : cost ratios in situations of low, medium and high soil fertility. It was also shown that farmers’ decision to deviate from the optimum and the allowable level of such deviation, depend much upon the prices of nutrient inputs in equivalent terms. In the medium-fertility situation (which applies in the study districts), the highest yield increment was noted with the maximum amount of N and P. The optimum application rate was 310 kg N and 200 kg P per ha, where the profit margin (the gap between gross returns and costs) is highest. This is an indication that soil-available K is likely to suffice the needs of the crop for optimum productivity, but this is largely dependent on the K fluxes in different soil types. The optimum rates were tested with actual soil data in the two study districts, against 5 tons of farmyard manure and a combination of the two. At both the coffee prices of 1250 and 2500 TZS kg-1, ISFM intervention (combination of organic and inorganic inputs) was more profitable than the other options, while coffee production showed to be more profitable in Hai than Lushoto.

Parametric Thermodynamic Models of Parchment Coffee Beans during HARC2S Dehydration

Parametric thermodynamic models have been developed to predict the temperature and moisture content wet base (M.C. (w.b.)) of parchment coffee beans during dehydration process in a hot air recirculation controlled-closed system (HARC2S). The principals of energy and mass transfer conservation during dehydration are the basis of the models. Experimental data of the moist air dry-bulb temperatures, relative humidity, and barometric pressure of the air entering and leaving the coffee beans are used to calculate the air thermal physical properties. These properties are used in the temperature prediction model. The coffee mass aspect ratio as determined by the HARC2S organic material chamber, predicted temperature, water-coffee effective diffusivity coefficient, and initial measured moisture content are required in the M.C. (w.b.) model. The experimental temperature data profile behavior appeared to be of a lumped-capacitance nature, while the M.C. (w.b.) experimental data had a linear constant rate decent behavior during dehydration. The linear decent appears to be an inherent characteristic property of the HARC2S dehydration process. The models prediction average errors as compared to the experimental data were, ± 1.8803% error for the temperature, and ± 1.8599% error for the M.C. (w.b.). The coffee processors will directly benefit from the developed thermodynamic models. They will have the capacity to continually monitor the parchment coffee beans temperature and M.C. (w.b.), while keeping the environmental integrity of the HARC2S during dehydration processes. The integrity is maintained by not opening the HARC2S until the desired M.C. (w.b.) of 10% to 12% is reached. Maintaining the environmental integrity of the HARC2S has the following advantages: (1) system energy efficiency is maintained within quasi-adiabatic environment; (2) coffee contamination from foreign objects is eliminated; (3) potential of bacterial and/or fungal growth are minimized. Thus, using the HARC2S has the potential benefit of insuring coffee bean safety and quality.

Quality of the coffee dryed on grounds with different surfaces and thickness layers

The present work aimed to evaluate the quality of coffee submitted to drying on grounds with different surfaces andthickness layers of grains, at Universidade Federal de Lavras, in July 2006. This experiment was carried out in a completelyrandomized design, factorial scheme 4x3x2, with four forms of coffee processing (mixture coffee, parchment coffee, cherry and unripeand floater), three types of grounds (earth, concrete and asphalt byproduct) and two thicknesses for coffee drying (thin and thick),amounting to 24 treatments. Two replicates per each treatment were utilized, amounting to 48 experimental units. About 15000 litersof coffee were picked over a cloth and dried on the different surfaces. Out of this total, 2400 liters were spread directly to the surfacesfor drying (mixture coffee). About 4800 liters were washed and separated by density difference. The portion floater and the portioncherry and unripe were dried separately on the surfaces. Finally, 9600 liters of coffee were washed, husked and dried on the surfaces.The coffee was turned 16 times a day by following the sun’s movement. After drying, samples of the coffees were taken, processed andsubmitted to evaluation of quality through the following analyses: sensorial and physical chemical analysis, Phenolic compounds,total titrable acidity, total solids, electrical conductivity, leaching of potassium, reducers and non reducers and total sugars. The resultsindicate that the type of coffee and the thickness layers have make strong influence in the chemistry and physical-chemistry characteristicsof coffee, and the sensorial analysis shows that the washed coffee dried in thin layers on concrete and asphalt surfaces provide betterbeverage quality.