Roasting Levels Research Articles

Characterization of Robusta Coffee Powder with Addition of Palm Sugar and Vanilla Powder to Improve The Quality of Robusta Coffee (Coffea canephora Pierre)

Bondowoso Robusta Coffee is a type of Robusta coffee that has a distinctive taste and high quality. The distinctive taste and high quality are obtained from the results of harvest management and post-harvest processing in accordance with Standard Operating Procedures (SOP). This research will be carried out by testing the characteristics of Robusta ground coffee with a mixture of palm sugar and vanilla flavoring to improve the quality of Robusta ground coffee. This was done by knowing the physicochemical and organoleptic properties of the mixed Robusta ground coffee. The aim of this research is to determine the interaction between roasting level and the composition of palm sugar and vanilla powder on the physiochemical and organoleptic properties of 3 in 1 Robusta Coffee. This research uses an experimental plan arranged factorially with the basic pattern of a Completely Randomized Design (CRD) with 4 replications. This design has two factors, the first factor is the roasting level and the second is the mixture composition. The results of this research show (1) The interaction of Roasting Level and Mixture (palm sugar and vanilla powder) has no significant effect on all observed variables such as water content, Brix content, pH value, and powder bulk density. (2) The effect of the main level of roasting has a very significant effect on the observed variables of rainfall density and an insignificant effect on the variables of air content, Brix content and pH value. (3) The effect of the main mixture has a very significant effect on the observed variables of air content, Brix content and powder bulk density and has no significant effect on the variable pH value.

Impact of Coffee Roasting and Grind Size on Acidity and Bitterness: Sensory Evaluation Using Electronic Tongue

Coffee flavor is profoundly influenced by numerous factors, including the origin’s terroir and variety, as well as post-harvest processing, drying, and sorting. Even specialty coffee beans, carefully selected for their high quality, can exhibit a wide range of flavor profiles depending on how they are roasted and ground. Traditionally, the coffee industry has used the Brewing Control Chart, which considers total dissolved solids (TDS) and extraction (E), to guide professionals toward achieving consistent flavors. However, this chart has limitations in representing the complex chemical composition and its influence on the sensory attributes of coffee. This study explores a more comprehensive approach to evaluating coffee quality by utilizing a taste sensing system (electronic tongue) to measure acidity and bitterness for full-immersion brewing. We investigate the impact of brew ratio and grind size on these taste attributes, while also considering the influence of roast level. Our findings demonstrate that finer grind sizes significantly affect TDS and E, while roast level and grind size significantly affect sensory attributes, as measured by the taste sensing system. This approach complements the traditional Brewing Control Chart by providing a more nuanced understanding of how roast level and grind size influence coffee flavor.

Sensory analysis of the flavor profile of full immersion hot, room temperature, and cold brewed coffee over time

With the growing popularity of cold brewed coffee comes a need for brewing efficiency while preserving the desirable flavor profile. Despite the wide use of full immersion brewing techniques, the effect of brew time on the dynamic sensory profiles of full immersion brewed coffee remains underexplored. Here, we investigated the relationship between coffee sensory quality and extraction dynamics, measured as Total Dissolved Solids (TDS) and Extraction (E) of full immersion brewed coffee at various roast levels, and brewing temperatures (4 °C, 22 °C and 92 °C), over brew time using a generic descriptive analysis method. Specifically, different brew time points were selected for different temperatures based on five targeted coffee extraction stages. Furthermore, the unique experimental design also explored a sensory-driven engineering research process. Roast level had the greatest impact on the sensory profile of the coffees, followed by brewing temperature, but brew time, especially the longer brew times as TDS plateaued, had subtler impacts than expected. Twenty-five of 28 sensory attributes were significantly different among the 30 coffee samples, indicating a single source green coffee blend can produce a wide range of complex sensory profiles using different combinations of roast level, temperature, and brew time. Specifically, the intensity of sweetness was negatively correlated with TDS, and 19 other attribute intensities were positively correlated with TDS. Interestingly, we found that certain long time cold brews had similar sensory profiles to those of some short time hot brews, suggesting the sensory profiles of certain hot brews and cold brews could possibly be matched through controlled preparation. Overall, our study demonstrated an approach of integrating food engineering and sensory analysis for product development, and our findings provide valuable insights into the extraction dynamics and sensory quality of full immersion brewed coffee and opens new brewing avenues for the coffee industry.

Perbedaan Metode Pengolahan Pascapanen dalam Memengaruhi Kadar Kafein Roasted Bean Kopi Robusta Argopuro

This study aims to determine the caffeine content of Argopuro Jember robusta coffee beans based on differences in post-harvest processing methods. The research was conducted at the Jember State Polytechnic Agricultural Products Processing (PHP) Laboratory and the Jember State University Integrated Testing Unit Laboratory in June-September 2022. The samples were robusta coffee logs originating from the Argopuro area of ​​Jember. The post-harvest coffee processing process is divided into four (4) methods, namely natural processing (dry process), semi-wet processing, wet (full wash process), and honey processing. Green beans from the results of each processing method are roasted at light, medium, and dark levels. The roasted bean caffeine content test from each post-harvest processing method at each roasting level was carried out descriptively (simple, without repetition). Overall, the caffeine content of the roasted beans produced in this study still meets the SNI 01-3542-2004 standard, a maximum of 2%. The caffeine content of Argopuro Jember robusta coffee roast beans at the light roast level ranges from 1.44-1.65%, 1.38-1.92% for medium roast, and 1.61-1.81% for dark roast. The highest caffeine content in roasted beans at each roasting level is 1.65% (dry process), 1.92% (full wash process), and 1.81% (full wash process), respectively. Meanwhile, roasted beans with the lowest caffeine content with a value of 1.38% are produced using the semi-wet process processing method at a medium roast level. The fluctuations in caffeine values ​​produced in this study indicate that post-harvest processing methods do not affect the caffeine content of roasted beans at light, medium, or dark roast levels.

Optimizing Split-reduced drip fertigation schemes of Arabica coffee based on soil microcosms, bean yield, quality and flavor in dry-hot region of southwest China

As a characteristic cash crop in Yunnan Province, China, Arabica coffee ranks first in the country in terms of cultivation area and production, but has always suffered from poor soil nutrient management and a lack of scientific basis for fertilization. It is not clear how to improve the soil microecological environment using split-reduced drip fertigation at different reproductive stages of Arabica coffee to improve bean yield and quality. Therefore, a two-year (2020–2022) field experiment was conducted on 5-year-old Arabica coffee trees in a dry-hot region with five split-drip fertigation patterns, F450, F600, F750, F900 and F1050. Using the local conventional fertilization (Fertilizer of 900 kg ha−1 year−1 only in berry expansion, and no fertilization in early flowering and berry ripening) as the control (CK). The effects of different fertilization modes on soil microecological environment, bean yield, nutritional quality and characteristic flavor were studied, and a comprehensive benefit evaluation model to assess bean yield and nutritional quality under different fertilization modes was established. The results showed that F900 significantly increased soil nitrate nitrogen, available phosphorus, available potassium, microbial population and enzyme activities at early flowering and berry ripening stages compared to CK, while F900 reduced soil nitrate nitrogen, available phosphorus and available potassium but increased soil enzyme activity and microbial population at the berry expansion stage. Compared with CK, F450 decreased bean yield, caffeine and chlorogenic acid content by 31.83 %, 23.73 % and 13.48 %, respectively, while F750 increased two-year average yield, raw bean fat, caffeine and chlorogenic acid content by 20.52 %, 12.37 %, 5.48 % and 11.17 %, respectively. The two-year average yield of F600 showed less difference from CK. Marginal yield was positive and then negative with increasing fertilizer application. Dry bean yield decreased at a total fertilizer application of 900 kg ha−1 year−1. Correlation analyses showed a positive correlation between soil microbial environment and nutrient quality of coffee beans, while different correlations were found between nutrients and volatiles at dark and medium roasting levels. Cluster analysis revealed that the relative contents of aldehydes, alcohols, phenols, pyridines, and pyrroles were higher under dark roasted condition, while the relative contents of ketones, esters, acids, and pyrazines were higher under medium roasted condition. Based on the Entropy weight-TOPSIS method, F750 had the highest combined benefits in terms of yield increase and quality improvement, and the total fertilizer application decreased by 16.67 % compared to CK, thus F750 treatment was the most suitable split-drip fertigation strategy for Arabica coffee in the dry-hot region of Yunnan. This study provided a reference for drip fertigation systems of Arabica coffee in dry and hot regions.

Performance of feature extraction method combination in arabica coffee roasting classification

Abstract Feature extraction is vital in electronic nose technology, particularly for classification tasks. However, challenges like noise, temperature variations, humidity, drift, and unwanted aromas can introduce inconsistencies in feature extraction, diminishing the machine’s classification capabilities. This study aimed to assess the electronic nose’s performance in recognizing aroma patterns of Arabica coffee at four roasting levels. It involved comparing 63 feature extraction method combinations derived from six primary methods (mean, skewness, kurtosis, standard deviation, maximum, minimum). After extracting features, Linear Discriminant Analysis (LDA) was used for dimensionality reduction and analysis. Subsequently, a Support Vector Machine (SVM) model was trained and validated using Stratified K-Fold Cross Validation to comprehend feature patterns and labels and determine hyperplanes for distinct classes. The results revealed that the best feature combination to classify arabica coffee aromas at various roasting levels was achieved by using a combination of mean, kurtosis, and standard deviation, with an accuracy of 86.11%, precision of 86.73%, recall of 86.11%, and MCC of 0.8159 in a training time of 0.0574 seconds. Utilizing LDA improved accuracy by 9.81% and MCC by 15.01%.

Pengaruh Konsentrasi Sorbitol dan Variasi Tingkat Penyangraian Terhadak Karakteristik Fisikokimia dan Organoleptik Kopi Robusta Cililin

Cililin is one of the robusta coffee producing regions in Indonesia, but there are still many people who do not know robusta coffee from Cililin, so an effort is needed to improve its quality. Coffee that goes through heating stages such as drying or roasting will cause several other chemical ingredients to change. Coffee processing can affect the characteristics and taste of the coffee produced. Soaking with sorbitol solution can retain moisture (humectant) in food and in processing that undergoes high temperature treatment so that it will not cause browning reactions One of the stages carried out in coffee processing using high temperatures is the roasting process. Therefore, a study was conducted to determine the effect of the difference in sorbitol concentration with roasting level on the characteristics of the Cililin robusta coffee products produced. This study consisted of two factors, namely sorbitol concentration (a1=10%, a2=15%, a3=20%) and roasting rate (b1 = Light Roast, b2 = Medium Roast, b3 = Dark Roast). Data processing using Two Way Anova on SPSS application version 26.0. The results showed that concentration had an effect on water content, color test and organoleptic response in color, aroma, and texture attributes, but did not affect the characteristics of caffeine levels, and pH. Roasting rate affects coffee characteristics, namely moisture content, caffeine content, pH, color test, and organoleptic response in color, aroma, and texture attributes. The interaction between sorbitol concentration and roasting rate affects the characteristics of robusta cililin coffee, namely moisture content and color test. However, it has no effect on the characteristics of caffeine levels, and pH. Keywords: Cililin Robusta Coffee, Sorbitol, Roasting Level

Effect of Different Roasting Levels and Manual Brewing Techniques on the Sensory Profile of Liberica Coffee with Honey Process

Liberica coffee is less popular than Arabica and Robusta coffees. One reason is that Liberica coffee has a less pleasant flavor than its other counterparts. Exploration on Liberica coffees and the processing impact on quality is still limitedly published. The objectives of this research are to evaluate the effect of different roasting levels and manual brewing techniques on the sensory profile of Liberica coffee. The green coffee beans used in this study are processed using honey. The Qualitative Descriptive Analysis (QDA) method evaluated sensory profiles, while a preference test was also performed. The brewed coffee’s basic physicochemical characteristics (color, pH, and Total Dissolved Solids (TDS)) were measured. The sensory evaluation applied a factorial Randomized Block Design with two factors, i.e., roasting level (light, medium, dark) and manual brewing technique (V60, French press), while the physicochemical characteristics analysis followed a nested design. The results showed that different roasting levels and manual brewing techniques significantly impacted 11 coffee sensory attributes, pH values, and panelists' preferences. The most preferred Liberica coffee honey processing treatment was light roast level with the V60 manual brewing technique.

Design of coffee roaster with controlled temperature system to maintain the sustainability of coffee roasting process

One of the most important process in producing coffee beverage is the roasting stage. Nowadays, roasting process is done using mechanic process by giving high temperature to coffee beans. However, the temperature is not controlled and the capacity tend too high or low, expensive and need a qualified coffee roaster to do this stage, which is not suitable for small and micro bussiness. This research aimed to answer those problems by designing a roasting machine that could control the temperature with a capacity of 4 kg per process. Result showed that the roasting machine could roast the coffee bean in 52 minutes to achieve the medium to dark roast level, and it is suitable for the small and micro bussiness according to the roasting profile and from the economic analysis this machine is feasible. Moreover, this coffee roaster is energy efficient and could provide a better livelihood for the user to produce the roasted beans even with no roasting experience.

Pengaruh Metode Pengolahan dan Level Roasting Terhadap Karakteristik Kopi Robusta Argopuro Jember

Jember, located in East Java, is renowned for its exceptional production of robusta coffee. The objective of this study was to analyze the physical properties of roasted robusta coffee beans sourced from Argopuro, Jember. The study utilized a fully Randomized Factorial Design incorporating two factors: processing method and roasting intensity. The processing method comprised four levels: natural process, honey process, semi-wet process, and full-wash process. Concurrently, the roasting level treatment consisted of three levels: light, medium, and dark. The observations encompassed the density of green beans, the density of roast beans, and the yield of roast beans. The green beans utilized in this investigation adhered to the quality criteria specified in the Indonesian National Standard (SNI) Grade 2. The research findings indicated that the processing technique had no substantial impact on the density of green beans. Neither the processing method nor the roasting level treatments had a different effect on the density or yield of the roasted beans. Nevertheless, the application of different roasting levels did result in a significant effect on both the density and yield of roasted coffee beans. The natural process approach yielded the maximum green bean density, weighing 365 kg/m3. The dark roast level resulted in the maximum bean density across all processing methods, including the natural, honey, semi-wet, and full-wash processes. The specific values for each method were 735.3 kg/m3, 637.3 kg/m3, 698.4 kg/m3, and 637.5 kg/m3, respectively. Moreover, the light roast level achieved the maximum output of roast beans, reaching 88.83%.

Determination of Caffeine, Chlorogenic Acid, Total Phenolic Contents, and Antioxidant Capacities for Arabica and Robusta Coffee from Vietnam

In Vietnam, the cultivation and production of coffee have been expanding over the past few decades and are known as an important part of the national economy. However, the scientific data regarding the internal compositions of coffee have still been limited, especially the changes during the processing, typically the roasting period. The present study aimed to demonstrate an insight into the variations in chlorogenic acid, caffeine, total phenolic contents (TPCs), and trolox equivalent antioxidant capacities for two common coffee species, that is, Robusta and Arabica, and three roasting levels, that is, light, medium, and dark. Generally, Robusta coffee performed higher chlorogenic acid, caffeine, and TPCs, resulting in dominant antioxidant capacities compared to Arabica. High Pearson correlation coefficients (calculated by SPSS) were found for most pairs of parameters, r > 0.80. Regarding roasting levels, a descending order was highlighted for most analytical parameters: light > medium > dark. Two parallel processes in the roasting period were revealed by observing the antioxidant capacities, that is, thermal degradation and formation of other antioxidants by the Maillard reaction. Principal component analysis (SIMCA-P 11) was attempted to discriminate the available coffee samples by their species and roasting levels, indicating proper classification (the cumulative variance is 95.3%).

Retraction Note: Use of electrochemical methods to determine the effect of brewing techniques (Espresso, Turkish and Filter coffee) and roasting levels on the antioxidant capacity of coffee beverage.

[This retracts the article DOI: 10.1007/s13197-022-05460-x.].

Performance Test, Noise, and Economic Analysis of Coffee Roasting Machines Rotating Cylinder

The roasting process carried out in this study was at the medium roast level, using a rotating cylindrical coffee roasting machine that used an electric heat source. This research aims to determine the performance and economic analysis of a rotating cylinder coffee roasting machine. Descriptive analysis in this study includes coffee roasting machine performance data (roasting temperature, moisture content, electrical energy requirements and noise) and economic performance data (NPV, IRR and BCR). The results of observing the performance of the machine obtained a roasting temperature of 205°C and a moisture content of 4.42%, in accordance with the Indonesian national standard (SNI) and the need for electrical energy in the heater was 3.18 kWh and in the motor of electric was 1.17 kWh. In this study, the noise analysis obtained showed the number 90 dB, which means it is less effective for operators in that environment. Meanwhile, the results of the economic analysis were obtained NPV, IRR and BCR respectively are IDR 225,363,266; 21.6 %; 5.18.

Effect of the roasting level on the content of bioactive and aromatic compounds in Arabica coffee beans

Effect of the roasting level on the content of bioactive and aromatic compounds in Arabica coffee beans

Evaluation of spontaneous fermentation impact on the physicochemical properties and sensory profile of green and roasted arabica coffee by digital technologies

There is a growing demand for specialty coffee with more pleasant and uniform sensory perception. Wet fermentation could modulate and confer additional aroma notes to final roasted coffee brew. This study aimed to assess differences in volatile compounds and the intensities of sensory descriptors between unfermented and spontaneously fermented coffee using digital technologies. Fermented (F) and unfermented (UF) coffee samples, harvested from two Australia local farms Mountain Top Estate (T) and Kahawa Estate (K), with four roasting levels (green, light-, medium-, and dark-) were analysed using near-infrared spectrometry (NIR), and a low-cost electronic nose (e-nose) along with some ground truth measurements such as headspace/gas chromatography–mass spectrometry (HS-SPME-GC-MS), and quantitative descriptive analysis (QDA ®). Regression machine learning (ML) modelling based on artificial neural networks (ANN) was conducted to predict volatile aromatic compounds and intensity of sensory descriptors using NIR and e-nose data as inputs. Green fermented coffee had significant perception of hay aroma and flavor. Roasted fermented coffee had higher intensities of coffee liquid color, crema height and color, aftertaste, aroma and flavor of dark chocolate and roasted, and butter flavor (p < 0.05). According to GC-MS detection, volatile aromatic compounds, including methylpyrazine, 2-ethyl-5-methylpyrazine, and 2-ethyl-6-methylpyrazine, were observed to discriminate fermented and unfermented roasted coffee. The four ML models developed using the NIR absorbance values and e-nose measurements as inputs were highly accurate in predicting (i) the peak area of volatile aromatic compounds (Model 1, R = 0.98; Model 3, R = 0.87) and (ii) intensities of sensory descriptors (Model 2 and Model 4; R = 0.91), respectively. The proposed efficient, reliable, and affordable method may potentially be used in the coffee industry and smallholders in the differentiation and development of specialty coffee, as well as in process monitoring and sensory quality assurance.

Classification of Nek Ali Coffee’s customers using the fishers method

This study uses discriminant analysis which aims to determine a model or formula that determines consumer groups who are interested in powdered, coffee bean, or instant coffee variants from several influencing variables, including coffee caffeine content, sugar content contained in coffee, coffee roasting level, quality coffee, coffee price, consumer age, consumer health, time of day consumer activity, and durability. The subjects of this research were the consumers of Nek Ali's Coffee with a total of 82 samples. The data obtained in this study were analyzed using discriminant analysis of three groups, namely the consumer group who are interested in coffee powder, coffee beans, and instant coffee. This study uses Discriminant Fisher's through SPSS software, the discriminant model or formula is obtained, as follows:Y1 = (0.08)X1 + (0.948)X2 + (0.332)X3 + (0.633)X4 + (0.576)X5 – (0.003)X6 + (1.825)X7 – (1.140)X8 = 0Y2 = (0.012)X1 + (0.868)X2 + (0.351)X3 + (0.591)X4 + (0.621)X5 – (0.002)X6 + (1.841)X7 – (0.592)X8 = 0Y3 = (0.081)X1 + (0.944)X2 + (0.349)X3 + (0.607)X4 + (0.581)X5 – (0.002)X6 + (1.971)X7 – (0.592)X8 = 0

The Determination of Triacylglycerols and Tocopherols Using UHPLC-CAD/FLD Methods for Assessing the Authenticity of Coffee Beans.

The authenticity of coffee beans was addressed in this study using an analytical method with minimal sample preparation to achieve simple oil extraction and through the implementation of cost-effective equipment. For this purpose, methods using UHPLC with CAD and FLD detectors were applied to detect triglycerides and tocopherols in coffee, respectively. The coffee samples included two main varieties: Arabica from Brazil, Colombia, Ethiopia, and Uganda, as well as the Robusta variety from Cambodia, Guatemala, India, and Vietnam. The samples were either in their green state or subjected to different roasting levels. The used methods successfully distinguished the Arabica and Robusta variants targeted in this study based on their tocopherols and TAG profiles, with the latter being particularly effective for discriminating the origins of the Arabica coffee, while tocopherols excelled at differentiating the origin of the Robusta coffee. TAGs and tocopherols were not affected by the type of roasting, from medium to very dark, suggesting it is possible to distinguish between coffee varieties independently from their degree of roasting. The obtained results hold valuable implications for future research regarding coffee fraud and authenticity.

Effect of fermentation on the physicochemical characteristics and sensory quality of Arabica coffee.

This work aims to assess the physicochemical characteristics and final sensory quality of Yellow Catuai IAC 62 Arabica coffee fermented with Saccharomyces cerevisiae. For such a purpose, a Composite Central Rotational Design (CCRD) was performed to investigate how fermentation time,temperature and pH conditions, moisture content and concentration of sugars and organic acids affect its sensory quality on two different roast levels in accordance with Specialty Coffee Association (SCA) protocols. It was found that fructose concentration decreased from 12g/L to around 5g/L during fermentation, regardless of temperature condition. Furthermore, longer fermentation times and higher temperatures have lowered sucrose and glucose concentrations from 4 to 2g/L and 7g/L to zero, respectively. Glycerol concentration was higher as time and temperature increased, and optimal conditions ranged at temperatures between 24°C and 32°C from 35 to 45h of fermentation time. pH decreased as fermentation time elapsed, but there was a more significant reduction due to higher temperatures, starting at around pH 5 and, lower than 4 under extreme conditions. Contents of organic acids such as acetic, propionic, succinic, and lactic acids, were measured at the final stage of each fermentation process under studied conditions. It was observed that coffee samples achieved final scores ranging from 81 to 85 (SCA score), even in longer times and extreme temperature conditions, thus all samples have been classified as specialty coffees. This work described the initial step towards parameterizing fermentation processes, given that the response variables of temperature and fermentation time, were optimal and enhanced the sensory quality of coffee as beverage. Saccharomyces cerevisiae, a commercial product which has already been made available for producers, can ensure an increase in the sensory quality of coffee.

Olfactory Evaluation of Geisha Coffee from Panama Using Electronic Nose

Geisha arabica coffee from Panama is featured in the world specialty coffee market. Its quality is assessed by sensory analysis with a panel of experts over several days. However, there is a risk of commercial fraud where cheaper coffees are mixed with pure specialty coffees. For these reasons, having an electronic nose (EN) device proves advantageous in supporting the cupping panel. It allows a greater number of fragrance and aroma analyses to be conducted per day, providing more objective results. In this study, an experimental EN equipped with a metal oxide semiconductor (MOS) gas sensor array was used. Olfactory evaluation of ground and infused Geisha coffee of different roast levels, brewing process, and purity was studied by EN, sensory analysis and chromatography. The sensory analysis perceived significant differences in fragrance and aromas in the light and dark roast levels of the samples. A total of 57 volatile organic compounds (VOC) were studied by gas chromatography. The EN data were analyzed chemometrically with principal component analysis (PCA) and predictive partial least squares (PLS). The data variances for two components were explained with values greater than 82%. The EN demonstrated its ability to differentiate the three levels of roasting, two production processes, and adulteration in the analyzed samples.

Concentration gradient inversion via sedimentation of coffee grounds in full immersion brewing

In full immersion brewing methods, the coffee grounds are fully submerged in water during the brew and then filtered out prior to consumption. If the brew is not agitated, most of the coffee grounds quickly float to the surface, but then eventually sediment to the bottom as they de-gas and become less buoyant. Although this behavior is readily observed, little research has investigated the impact of the transient sedimentation process on the concentration profile of total dissolved solids (TDS) within the brew. Here, we report that unagitated full immersion brews undergo a concentration gradient inversion midway through the brewing process and that the time scale of the inversion depends sensitively on the roast level of the coffee grounds. Systematic measurements of the TDS versus both depth and time reveal that the brew contains a region of nearly twice the concentration near the top air/liquid interface at the beginning of the brew, but then the higher concentration region inverts to the bottom of the container as the brew progresses. Time-lapse photography observations indicate that the time scale of the gradient inversion is consistent with the average rate of sedimentation, which occurs up to a factor of three slower for darker roasts. A key implication of our results is that sensory evaluations obtained via the traditional “cupping” method used widely in the coffee industry might be confounded by differences in TDS for different roast levels.