Coffea arabica (Arabica) and C. canephora (Robusta, Conilon) have satisfied the requirements of the coffee sector for the last 125 years. In the face of myriad challenges, most notably climate change, the coffee species crop portfolio requires diversification to ensure the long-term sustainability of coffee production. In addition, the specialty coffee sector relies on continual diversification and creativity to satisfy the requirements of its adherents, including the enrichment and diversification of the sensory experience. In this contribution, a review is presented on the status of ‘other’ coffee species to supplement C. arabica and C. canephora, based on research and first-hand experience. The aim is to address misinformation (e.g., global production figures, yields, climate tolerances, and cup profiles) concerning wild and ‘other’ species, identify opportunities, and highlight constraints. In the short-term, Libericoid coffee species, including C. liberica (Liberica) and C. dewevrei (Excelsa) coffee, offer substantial opportunities, especially for climate resilience. Over the longer term, other species (such as C. stenophylla) and inter-species hybrids offer considerable promise. Unlike C. arabica and C. canephora, research and development for other Coffea crop species is in its infancy and will require significant development. One of the other major constraints for Coffea crop species development is access to genetic resources. In the face of climate change, the coffee breeding challenge is now more demanding than ever.

Proceedings: Davis, A.P. Beyond the Orthodoxy: An Overview of the Potential of ‘Other’ Coffee Species for Crop Use and Their Associated Challenges. Proceedings 2024, 109, 4. https://doi.org/10.3390/ICC2024-18155

For many years, coffee has maintained its place in Turkey as Turkish coffee (i.e., boiled, finely ground, unfiltered), and has become globally recognized. However, in recent years, especially for young people, filter coffee has become more popular, instead of Turkish coffee. As is generally known today, climatic conditions and processing techniques have an impact on the constituents of coffee. It is also thought that the finer grinding of Turkish coffee may affect the variability of the coffee contents. The mentioned popularity of the coffee beverage is also causing an increased interest in its nutritional and functional properties as well as its chemical constituents. Therefore, an analytical determination of the coffee ingredients is essential. Taste may be the most important criterion for coffee consumption for most consumers, but the health benefits should not be underestimated. Coffee has an antioxidant effect due to the phenolic compounds present, such as chlorogenic acid. It is also known to prevent cellular damage, which has led to increased interest in its antioxidant properties. The aim of this study was to investigate the total chlorogenic acids (CQAs), caffeine and antioxidant capacities of coffees commonly consumed in Turkey. For this purpose, three green and three roasted coffee samples of the Coffea arabica, Coffea canephora and Coffea liberica varieties were selected for this study and characterized. Different targeted mass spectrometry (LC-MS/MS) methods were developed to encompass the above-mentioned ingredients. The roasting process significantly increased the caffeine content in three roasted samples compared to green coffees. These values ranged from 1.2 g per 100 g dry mass (DM) in green coffees to 2.6 g per 100 g DM in roasted coffees. It could be shown that the most dominant CQA contained was 5-CQA. While the amount of CQA in green coffees is approximately 49–64%, it decreases down to 33–41%, by isomer conversion partly, to 4-CQA and 3-CQA in the roasting process. The highest value was found at 3.5 g/100 g DM. The highest value for the antioxidation capacity was 4.4 g ascorbic acid equivalents/100 g DM roasted coffee and the lowest value was 2.4 g/100 g DM in green coffee. This study was the first attempt to demonstrate the presence of different CQAs, caffeine and antioxidation capacity in coffee beans from the market in Turkey and needs to be followed up further with a larger sample size in future studies.

Proceedings: Özpınar, H.; Morche, J.R.; Rawel, H.M. Determination of Chlorogenic Acid, Caffeine and Antioxidant Capacities in Turkish-Style Coffee Bean Samples. Proceedings 2024, 109, 12. https://doi.org/10.3390/ICC2024-18156

The genetic conformity of the cultivated varieties of coffee is key for the sustainability of coffee growing. In the past years, various studies have shown that genetic conformity was overall low. This situation is mainly due to a lack of professionalization in the coffee seed sector. However, this can impact the economic performance of growers who expect yield, disease resistance, and/or cup quality from their coffee plants. With the sponsorship of Lavazza, RD2 Vision has launched the “Coffee Genetic Discovery”. The aim of “Coffee Genetic Discovery” is twofold: to democratize the genetic analysis of cultivated coffee varieties and provide guidelines for improving the professionalization of the coffee seed sector. Coffee growers (Coffea arabica for this first edition) from 24 countries took part in a draw. One hundred winners benefited from a free genetic analysis of their favorite coffee plants. Each grower received the results individually. Most participants were from Central America and Mexico (50%), followed by Asia (23%) and then Africa (14%) and South America (13%). A total of 73% of the participants had an idea of what their cultivar was, while 27% had no idea. Most submitted samples were from the Core Ethiopian genetic group, which includes Geisha, Chiroso, and Sidra, showing the interest of farmers for cultivars with a high cup quality. Two thirds of the supposed cultivars were genetically conformed, while one third was not. This confirms the need for a more professional seed sector.

Proceedings: Montagnon, C.; Serito, B. Democratizing Coffee Genetics: Outcomes of the “Coffee Genetic Discovery” Project. Proceedings 2024, 109, 32. https://doi.org/10.3390/ICC2024-18159

Due to the European Regulation on Deforestation-Free Products (EUDR), coffee and other commodities and their derived products from deforested areas will be prohibited from being placed on the European Union (EU) market starting in December 2024. With the “EUDR Coffee Check”, a comprehensive tool was developed, in collaboration with the German Coffee Association (DKV), combining a database solution with automated analysis methodologies, combined with a web-frontend, to support the EUDR compliance of the coffee industry. The tool supports the gathering of verifiable information to ensure that coffee is deforestation-free after the 31 December 2020 EUDR cutoff date. To determine deforestation-free status, deep learning-based mapping methods on satellite imagery along with open access local and global datasets were applied to develop a 2020 forest reference map that aligns with the defined EUDR forest categories and the cutoff date. The tool can be used to conduct automatic deforestation checks by comparing coffee farm locations with reference forest maps from 2020 and raises a potential deforestation alert. Potential deforestation alerts are identified as critical cases based on the annually updated series of land use changes and/or deforestations observed within the base 2020 forest areas after the cutoff date. The tool also allows users to conduct a structured risk assessment of the provided geo-coordinates of production areas and the supply chain to document the complete exercise of the required EUDR due diligence process. The tool uses internationally recognized indices and statistics, such as UNDP, UNICEF, World Bank, and many more, to calculate a risk score to evaluate governance and human rights risks such as child labor, forced labor, or corruption associated with the sourcing regions. The presence of forests, deforestation risk, and maps providing information on the protected areas of indigenous people are used to identify the coffee production areas’ proximity and relative risk exposure to provide a full picture of the risk factors in line with the EUDR requirements. In addition to the detailed analysis of deforestation risk alerts, the EUDR Coffee Check provides a questionnaire that guides the user through the structured process to supplement the risk assessment and documentation of legality. Following focused questions and providing potential answers, the user is enabled to evaluate the risk for non-compliance according to the exact requirements of the EUDR and provides guidance on risk mitigation measures, such as the implementation of internal due diligence strategies, the usage of third-party verification schemes to increase reliability through on-site audits, or the usage of traceability platforms. The developed EUDR Coffee Check supports companies to comply with the EUDR due diligence obligations by analyzing, documenting, and reporting on individual shipments and the associated production areas and can be used by operators, traders, or any actor along the supply chain, including authorities, to control the checks at their discretion. The tool is offered at a nominal fee structure based on a customized term of usage.

Proceedings: Rothe, P.; Celik Schoreels, I.; Phuntsho, P.; Henke, J. EUDR Coffee Check: A Tool to Support the Coffee Sector to Become Compliant with the European Union Regulation on Deforestation-Free Products (EUDR). Proceedings 2024, 109, 21. https://doi.org/10.3390/ICC2024-18160

There is a lack of innovation and process development in the post-harvest processing of coffee. The prevailing methods, such as wet washing, semi-dry/honey and natural drying, are still used to improve the sensory quality of coffee. Little attention has been paid to mitigating natural resource issues such as the availability of clean water and wastewater pollution. The aim of this research was to develop a simple process for upgrading Coffea canephora var. Robusta coffee with low water consumption and low effluent pollution. A controlled fermentation process was developed with optimal standard parameters. Process water requirements were reduced by 80% and effluent emissions were reduced by the same factor. A single-origin Robusta coffee drink was evaluated by sensory experts. The sensory profiles and roasting profiles were also evaluated. This innovative process resulted in the development of a pleasantly balanced single-origin Robusta coffee (not blended with other coffees) with a full body and rich flavour profile.

Proceedings: Mhlanga, E.G. A New Post-Harvest Process of Upgrading Coffea canephora (Robusta) Coffee Beans. Proceedings 2024, 109, 18. https://doi.org/10.3390/ICC2024-18161

The coffee supply chain generates over 10 million tons of waste annually, with 70% comprising the fruit pulp and skin. This study investigates using coffee cherry flour from fresh coffee husk as an alternative ingredient in pastries with baking powder and baker’s yeast. We characterized the nutritional and physicochemical properties of this flour, developed high-fiber recipes, and evaluated the effects of substituting wheat flour with varying proportions of coffee cherry flour in plain cakes and sweet yeast breads. We found that coffee cherry flour reduced yeast dough volume increase and pastry specific volume in the coffee cherry flour pastries but enriched them with higher mineral and dietary fiber content compared to the wheat flour pastries.

Proceedings: Reineke, A.-J.; Stadelmeyer, K.; Acuña-Gutiérrez, C.; Jiménez, V.M.; Chacón-Ordóñez, T.; Acosta, O.; Müller, J. Evaluation of Coffee Cherry Flour as a Functional Ingredient in Pastries. Proceedings 2024, 109, 31. https://doi.org/10.3390/ICC2024-18162

In 2016, the International Agency for Research on Cancer (IARC) classified the drinking of very hot beverages above 65 °C as “probably carcinogenic to humans” (Group 2A), with esophageal squamous cell carcinoma (ESCC) particularly associated with the habit. As this finding may have practical implications for the coffee industry, there appears to be a need to critically reassess the often extremely high standard brewing and serving temperatures used in coffee preparation. This study presents a summary of the most recent IARC assessment on very hot beverage consumption and investigates the influence of brewing temperatures (80, 86, and 93 °C) and roasting degrees (light, medium, and dark) on the sensory profile of manual drip coffee. As the evidence linking very hot beverage consumption to increased ESCC risk has grown stronger, the IARC classification is likely to be upgraded in coming years. As the roast intensity increased, assessors preferred coffees brewed at lower temperatures and most of them were not able to distinguish brews extracted at different temperatures. Given these results, the potential for lowering the brewing temperature in commercial settings is clear. This approach not only enhances consumer safety, but also positions businesses as leaders in health-conscious practices, potentially redefining standards across the industry for the optimal temperature of coffee serving that aligns with both flavor and health research findings.

Proceedings: Lachenmeier, D.W.; Morgado, J.; Maia, A.; Farah, A. Managing Cancer Risk from Very Hot Beverages: Influence of Brewing Temperature on Sensory Characteristics of Coffee. Proceedings 2024, 109, 13. https://doi.org/10.3390/ICC2024-18163

‘Freshly roasted’ has long been considered the ultimate indicator of coffee quality. This study challenges this concept by arguing that coffee, as a complex processed agricultural product, undergoes a critical developmental ‘maturation’ phase after roasting that is significant for its sensory experience. Thus, this study investigates whether there is (i) a discernible sensory effect and (ii) a perceptible consumer preference for ‘freshly roasted’ coffee beans by means of a triangle test (ISO 4120:2021) combined with a hedonic preference test (ISO 8587:2013) on 42 untrained participants. The triangle test results indicate that there is a significant difference between the samples, and a slight majority expressed a preference for not ‘freshly roasted’ coffee, encouraging a more nuanced approach to the issue.

Proceedings: Zimmermann, Y.C.; Schwarz, S. Freshly Roasted Coffee Re-Evaluated: A Pilot Study on the Impact of Post-Roast Maturation on Sensory Experience. Proceedings 2024, 109, 8. https://doi.org/10.3390/ICC2024-18164

The genetic diversity of wild Coffea species holds immense potential for the enhancement of cultivated coffee trees, offering solutions to challenges such as disease resistance, climate adaptability, and yield improvement. This study leverages modern genomic approaches to investigate evolution and variations among wild Coffea species. By employing advanced sequencing technologies and comparative analysis, the aim was to understand the molecular evolution of these wild species, identifying key genes and genetic markers which contribute to desirable traits. This research integrates comprehensive genomic data analysis with field studies to provide an understanding of the genetic diversity within wild Coffea populations. The aim of this research is to target significant genetic variations that can be harnessed to develop superior coffee cultivars, ensuring sustainability and resilience in the face of changing environmental conditions. This study not only highlights the importance of preserving wild Coffea species but also underscores the role of genomic research in unlocking their potential for coffee breeding programs. By bridging the gap between conservation and cultivation, this work paves the way for future innovations in coffee agriculture.

Proceedings: Guyot, R.; Gonzalez, L.; Bezandry, R. Wild Coffea Species: A Modern Genomic Approach to Unravel Variations for Future Cultivated Coffee Improvement. Proceedings 2024, 109, 23. https://doi.org/10.3390/ICC2024-18165

Dichloromethane (DCM) is extensively used around the globe in various applications, such as in closed industrial installations for food processing or pharmaceutical extractions (vitamins, antibiotics, etc.). In the coffee sector, it is used as an extraction agent for the decaffeination process of green coffee beans. Due to its low boiling point, ranging at approx. 40 °C, DCM can be easily removed subsequent to caffeine extraction by applying state-of-the-art solvent stripping processes. The intention of this study is to assess how much DCM, if any, is present in decaffeinated coffee packages as sold to the consumer, as well as how much of the extraction solvent residue is transferred into the finally prepared, consumable coffee beverage. This study sets out to highlight DCM contents of decaf coffees, directly taken from six EU countries’ supermarket shelves. In addition, DCM mass transfer rates from roasted coffee matrices into the corresponding, variously prepared beverages (drip percolated coffee, French press) are determined. All analyses were performed applying a Headspace-GC-MS technique. All presented data demonstrate that DCM residues in the 34 coffee samples analysed have contents well below the DCM maximum residue limits for roasted coffee both in the European Union (2 mg/kg) and the USA (10 mg/kg), with an average of 0.127 mg/kg, median value of 0.059 mg/kg and P95 of 0.444 mg/kg. Furthermore, this study shows that DCM mass transfer rates from the coffee matrices into the corresponding beverages have, for drip coffee, an average of 24.7% and median of 26.8%, and for French press, an average mass transfer of 41.9% and median of 43.1%.

Proceedings: Fabian, M.; Süße-Herrmann, O.; McGaffin, G.; Hielscher, J. Mass Transfer of Dichloromethane from EU Retail Roast and Ground Decaffeinated Coffee into Prepared Beverages. Proceedings 2024, 109, 33. https://doi.org/10.3390/ICC2024-18166