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Abstract. Demand on high quality coffee for consumption is continually increasing not only in the consuming countries (importers) but also in the producing countries (exporters). Coffee quality could be affected by several factors from farm to cup including the post-harvest processing methods. This research aimed to investigate the influence of different post-harvest processing methods on physical and sensory quality of Java Arabica green coffee beans. The two factors being evaluated were three different post-harvest processing methods to produce green coffee beans (natural/dry, semi-washed and fully-washed processing) under sun drying. Physical quality evaluation was based on The Indonesian National Standard (SNI 01-2907-2008) while sensory quality was evaluated by five expert judges. The result shows that less defects observed in wet processed coffee as compared to the dry processing. The mechanical drying was also proven to yield a higher quality green coffee beans and minimise losses.

Post-harvest processing is known as one of the most important factors that influence coffee flavour quality. Amongst many different fermentation techniques, honey and wine processing are getting more popular in the country these days. Therefore, many single origins coffees processed following these techniques. There are also several manual brewing techniques readily available for Indonesian coffee consumers, and those techniques may give distinctive sensory characteristics to the brewed coffees. This research was aimed to study the effect of manual brewing techniques i.e. Indonesian “tubruk” method, Vietnam drip, cold brew, and aero press on the sensory profiles of two Arabica coffee samples i.e. Aceh Gayo wine process and Bali Kintamani honey process. As many as 10 selected, validated and trained student panellists were employed to assess 33 sensory attributes based on Sensory Descriptive Analysis method. Data analysis was performed using Minitab 17. The result has indicated that 22 to 24 sensory attributes were significantly different (α = 0.05) as influenced by different manual brewing techniques, while different coffees with different post-harvest processing created significant effect particularly in the fermented, berry, woody, and sweet notes.

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Coffee consumption in the world is continuously growing and demanding high quality. Coffee cup quality is a complex matters involving several factors that includes post-harvest processing factor. The objective of this research is to investigate the impact of different coffee post-harvest processing methods i.e. fermentation methods (natural/dry, semi-washed and fully-washed processing), and drying methods (mechanical and sun drying) on the sensory quality of Java Arabica medium-roasted coffee beans. The sensory quality was evaluated through cupping test employing five expert judges. The result revealed that different post-harvest processing factors has a significant influence on coffee sensory quality, particularly on four cupping attributes, namely fragrance/aroma, flavour, defects and final scores. Fermentation using more water and controlled mechanical drying were found to yield a better coffee sensory profile due to less identified defective characters in the cup. Nevertheless, different processing created specific coffee character that would have its own market provided the quality is properly controlled.

Coffee trade is a billion-dollar industry and coffee remains one of the most traded commodities of economic importance to both the countries producing, and the countries consuming coffee. To ensure demand, it is of great importance to constantly maintain and, where possible, improve its quality.Flavour is crucial to coffee quality. However, describing coffee flavour is a very complex task as it is influenced by numerous factors from the farm to cup. These factors influence compositional properties of coffee and have a large impact on the perceived flavour.The ultimate aim of this project was to understand how different components in coffee influence flavour perception. The approach involved an exploration on the sensory and physicochemical profiles of sensorily diverse 26 commercial single-origin 'specialty' coffees. Sensory evaluation of these 26 selected coffees involves assessment on the brews while coffee ground and extracts were analysed for physicochemical profiles. An analytical method was developed and applied for rapid quantification of the targeted volatiles compounds in coffee. The results of sensory and physicochemical evaluation were modelled using a multivariate analysis to explore the relationship between attributes and to know potential sensory markers that could contribute to coffee flavour.Coffee proved to be a highly challenging matrix to study and required special preparation and presentation of individual samples at consistent temperature during sensory evaluation. Nevertheless, sensory profiles for the diverse range of coffees was achieved.Certain coffees were clearly distinctive: Ethiopian coffees registered fruity, citrus and aromatic spice sensory profile notes, Australian coffees exhibited milder profiles, while India Robusta coffees generally possess smoky, woody, earthy and cereals profile.Three analytical stable isotope dilution analysis/gas chromatography-mass spectrometry (SIDA/GC-MS) methods were developed and applied to quantify 27 key volatile compounds which were targeted due to their reported importance to coffee flavour. These methods involved a headspace-solid phase microextraction/gas-chromatography (HS-SPME/GC-MS) of coffee, steam distillation extraction of coffee followed by a HS-SPME/GC-MS and direct liquid injection of a steam distilled extract of coffee to GC-MS.ii The 26 medium-roasted single-origin coffees investigated were quite diverse in physicochemical properties. It was clear that some coffees showed distinct physicochemical characters, for example, Robusta coffee contained doubled the caffeine content, higher concentrations of dicaffeoylquinic acids (diCQAs), higher pH, and higher L*

The “natural coffee” produced through sun-drying has been a common coffee post-harvest processing practice and well-known to exhibit specific sensory characters. However, the sensory profile of coffee in a cup could be influenced by many other factors including the brewing techniques. The objective of this research was to study the effect of different manual brewing techniques i.e. Indonesian “tubruk” method, Vietnam drip, cold brew, and aero press to the sensory profile of two Indonesian “natural coffees” origin i.e. Robusta Gayo and Arabica Kerinci. Evaluation was performed on 33 sensory attributes using Sensory Descriptive Analysis method employing 10 trained student panellists. Data analysis was performed using Minitab 17 and the Unscrambler® X MVA software. The result showed that in total; as many as 21 attributes were rated by the panellist. The two samples showed different sensory profiles, particularly in some sensory attributes assessed. The different manual brewing techniques was also found to have significant impact (α = 0.05) on 17-18 sensory attributes, showing that each technique will be responsible for certain sensory characters perceived by coffee consumer.