How is colombian coffee processed

Acetobacteraceae are commonly reported in commensal and symbiotic relationship with sugar-rich diet insects, such as bees, Drosophila , and ants As the coffee bean pulp presents high sugar content, Acetobacteraceae can disperse into fermentation sites using the insects as dispersion vectors Leuconostoc was also a dominant microbial group in coffee fermentations inside Brazil, Mexico, Ecuador, Taiwan, and India biomes 6 , 9 , 10 , 33 , This confirms Leuconostoc as a core bacterium in coffee-bean fermentation worldwide.

In addition, LAB belonging to the families Streptococcaceae Lactococcus and Lactobacillaceae Lactobacillus and Pediococcus were detected in significant presence during the initial and final fermentation phases, respectively Fig. The presence and dominance of LAB indicates that these microorganisms are adapted to the environmental conditions and stressor factors that coffee fermentation imposes, such as low pH, availability of sugars, and competition with other microorganisms These lactic acid-producing bacteria contribute to the demucilage process of coffee pulp and inhibition of the growth of pathogens, spoilage microbes, and toxin-producing fungi Other LAB members found in low proportions in this study, such as Weisselia and Fructobacillus , were reported with significant presence in coffee fermentations of Brazil and Mexico 6 , These LAB genera possess specific metabolism, such as improved fructose consumption and extracellular polysaccharides production, which may induce metabolite changes in the Colombian process Further investigations are necessary to obtain a comparative microbial diversity and activity between different coffee producing regions.

Pichia nakasei was the dominant group within eukaryotes, followed by Candida sp. Pichia have been reported as a dominant yeast in coffee beans fermentation conducted in Brazil, Tanzania, and China 7 , 8 , 38 , 39 ; however, this is the first study to report the dominance of P. This species have been isolated from fruit or fruit products, and classified into P.

Other fungal groups were found at specific time of fermentation process, including Schwanniomyces , Bensingtonia , Candida vanderwaltii , Martiniozyma asiatica , Physciceae, Tremellaceae, and Lobulomycetales Fig. Because coffee fermentation take places in an open tank, the process is susceptible to contaminations from human contact, air, insects, and dead leafs 41 , In addition, some extremophile yeasts, such as Dipodascus tetrasporeus and Lobulomycetales, were for the first time reported in coffee fermentation process.

These yeast species are generally associated with deep Pacific Ocean sediment and subglacial sediments of the Andean Mountains 43 , 44 , The changes in major non-volatiles sugars, organic acids and ethanol and volatiles acethaldeyde, ethyl acetate and hexyl acetate metabolites were quantified in the course of fermentation time Fig.

The initial composition of Colombian coffee pulp was 0. This observation can be a result of the action of hydrolytic enzymes produced by microbial metabolism, which promotes the breakdown of pectin, cellulose, sucrose, and other coffee pulp complexes carbohydrates, into monomers of glucose and fructose 6 , A residual content of 0. The presence of residual sugars is an evident characteristic of spontaneous coffee fermentations, as previously observed in Brazil, Ecuador, India, and Mexico 6 , 10 , 47 , Course of sugar consumption, metabolite formation, pH, temperature and Brix during Colombian spontaneous coffee beans fermentation process.

No significant changes were observed in the contents of ethanol, citric acid, acetic acid, and succinic acid Fig. On the other hand, lactic acid showed a significant increase, reaching maximum concentration of 0. The steady increase in lactic acid content is correlated to LAB growth that display fermentative metabolism with usually lactic acid as the main metabolic end product This is also an important end-metabolite associated with coffee fermentation, which assist in the coffee-pulp acidification process without interfere in the product final quality 32 , 36 , 49 , The major volatiles measured by GC were acetaldehyde, ethyl acetate, and hexyl acetate Fig.

Among these, acetaldehyde showed a greater variation through the fermentation, ranging from 0. Acetaldehyde is predominantly produced by yeasts of the genus Pichia , which have low alcohol dehydrogenase activity responsible for the conversion of acetaldehyde into ethanol This aromatic molecule is widely known to contribute to fruity sensory notes in alcoholic beverages The direct relationship between acetaldehyde and coffee quality is, however, not yet known.

It is possible to speculate that an intense diffusion during fermentation may have a complementary function in the development of fruity notes of Colombian coffees. Further studies on this relationship are needed. A total of 20 minor volatile metabolites were detected through the fermentative process by GC—MS, including 5 organic acids, 3 alcohols, 1 aldehyde, 4 esters, 2 ethers, 1 furan, 2 hydrocarbons,1 phenol, and 2 terpenes Table 2. The main metabolites found at the beginning of the fermentation process were 1,2-benzenedicarboxylic acid, 9,octadecadienoic acid, and 1-pentadecanal.

However, the concentration of these compounds was significantly reduced with the fermentation period, possibly due to evaporation or microbial use as precursors in metabolic routes 3.

On the other hand, the content of 1-hexanol, 2-heptanol, nonanal, isoamyl acetate, 2,2,6-trimethyloctane 2-hydroxy-benzoic acid, linalool, and limonene, which can be formed from microbial activity, increased gradually through the fermentation process.

In this respect, LAB and yeasts have a pivotal influence through the generation of different aroma-influencing molecules via central carbon and nitrogen metabolism 3. Some microbial groups reported in this study, including Pichia nakasei , Candida sp.

For coffee, however, more studies are necessary to evaluate the direct impact of this compound on the final product quality. The Colombian coffee beans constitution had 7. The coffee bean composition remained unchanged after the fermentation and drying processes. This indicates that microbial activity and drying process do not interfere in the composition of major compounds inside the coffee beans.

The major organic acids and sugars concentration in the fermented coffee beans is similar to those found in Brazil and Ecuador 10 , 36 , and are considered key precursors of coffee-impacting molecules generated during the roasting 5. A total of 15 volatiles were detected by GC-MS in fresh unfermented and fermented coffee beans, including organic acids, alcohols, aldehydes, alkanes, terpenes, and aromatics Table 3. Interestingly, most of these compounds have increased significantly after the fermentation process.

In particular, the increase of aldehydes e. As the volatile compounds present low olfactory threshold, their incorporation in the chemical composition of the beans can attribute desirable and pleasant floral, fruity and citric sensory notes to the final beverage.

On the other hand, some compounds, such as styrene and limonene, may have been originated from the seed germination during the processing 3 , In summary, the Colombian spontaneous coffee beans fermentation process was characterised by the dominance of Leuconostoc and Pichia nakasei.

The metabolic activity of these microbial groups resulted mainly in the production of lactic acid and acetaldehyde. In addition, other microbial groups were present, contributing to the formation of a complex array of metabolites. Interestingly, 56 fungal and bacterial genera were reported for the first time in the coffee fermentation process.

These microorganisms are mainly associated with local environments and migration from proximal biomes, indicating the formation of microbial niche-specific and metabolic activity in the Colombian spontaneous coffee fermentation process. Our data contribute to a better understanding of microbiome composition and open perspectives on their application in the enhancement of coffee fermentation process, such as production of high-quality coffee beans, selection of specific microbial groups for flavour modulation, and potential candidates for biological markers of Colombian coffees.

Extracted DNA quality was cheked on a 0. Shanghai, China. ACE, Chao 1, Shannon, and Simpson index were used to analyze the richness and biodiversity of the microbial communities.

Then, the supernatant was diluted at a ratio with distilled water and filtered using a 0. Major volatile compounds were quantified by gas chromatography GC.

The volatiles present in the headspace were manually extracted with a 1. Nitrogen was the carrier gas used, at a flow rate of 1. The volatile compounds were identified comparing the peak retention times against standards.

The quantification of volatile compounds was expressed as ethanol equivalent. Volatiles were identified comparing each mass spectrum either with the spectra from authentic compounds or with spectra in reference libraries. The relative abundance of each volatile compound present in the headspace was showed as peak area times 10 5.

Then, beans were grounded using an electric coffee grinder. Unfermented coffee beans were included as a control. For HPLC analysis, a cold extraction was done by adding 0.

Samples were centrifuged, filtered using a 0. Analyses were performed using the SAS programme, version 7. ICO, I. Report on coffee total production by all exporting countries in thousand 60 Kg bags. Available at, www. Lara-Estrada, L. Effects of altitude, shade, yield and fertilization on coffee quality Coffea arabica L. Caturra produced in agroforestry systems of the Northern Central Zones of Nicaragua.

Google Scholar. Pereira, G. Exploring the impacts of postharvest processing on the aroma formation of co ff ee beans — A review. Food Chem. Article Google Scholar. Microbial ecology and starter culture technology in coffee processing. Food Sci. Lee, L. Coffee fermentation and flavor - An intricate and delicate relationship. Avallone, S. Microbiological and biochemical study of coffee fermentation.

Masoud, W. Yeast involved in fermentation of Coffea arabica in East Africa determined by genotyping and by direct denaturating gradient gel electrophoresis. Yeast 21 , — Isolation, selection and evaluation of yeasts for use in fermentation of coffee beans by the wet process. Food Microbiol. Carvalho, D. D, Pereira, G. Food Technol. De Bruyn, F. PubMed Google Scholar. Conducting starter culture-controlled fermentations of coffee beans during on-farm wet processing: Growth, metabolic analyses and sensorial effects.

Food Res. Evangelista, S. Improvement of coffee beverage quality by using selected yeasts strains during the fermentation in dry process. Current state of research on cocoa and coffee fermentations. The result is coffee with balanced acidity, sweetness, and body. Walking between Caturra crops on Finca Monteblanco. Rodrigo tells me that he and Claudia are only producing small amounts of cold fermented coffee — they have the capacity to produce four bags every three days.

But he says that it is profitable and that customers are enthusiastic about the cup profile and quality. If washed coffee is in demand and a well-established method in Colombia, why are some producers choosing to experiment with other techniques?

The decision depends on individual resources, including infrastructure and economic support. However, for some producers, a new processing method can mean better cupping scores, increased market access, and greater profit. Then we started to do some experiments with honey processing and we realised that the cup profile increased. From a cup that originally scored 82, we got an point cup profile.

With new methods comes risk: it takes time to learn a new technique, money to invest in equipment, and there is the danger of ruining a lot with improper processing. Here, technicians evaluate the quality of coffee and can provide feedback and advice to producers. Coffee flowers at Hacienda El Obraje.

New processing methods can allow producers to offer high-quality coffees with a unique selling point, such as natural or cold processed Colombian coffees rather than more typical washed ones from this country. This is one way to gain attention from the industry and increase market access. Our first step was to show a great product. A good product opens doors.

Rodrigo tells me that producers should aim to have buyers visit their farms to make direct purchases, and that this depends on producing high quality coffee. Washed and natural coffees dry on raised beds. The specialty world is a low percentage of purchasing in world production. Producing high-quality coffee can also open the door to national competitions and allow beans to be chosen by baristas for professional championships.

For example, Rodrigo earned the top score in the cup-quality contest by fertilizer company Yara Colombia in All of the producers I met are focused on high quality and dedicated to improvement. They were willing and able to take a risk on experimentation.

Enjoyed this? This is the Colombian method. When washing with water, the pulp, fruit and skin is removed. In the second method, the cherry is put to dry as is. The cherry undergoes a fermentation process. When dry, the skin is removed from from the coffee beans. This process is less common and more delicate for, if not dried properly, one bad coffee bean can ruin the whole batch with a bitter taste. The taste is just that of the coffee pit. It ferments and the bacteria metobolizes the sugar which influences the taste of the bean.

They then remove the skin and the rest of the remains and what remains is a taste that has been influenced by the fermentation process. There is a sweet taste that hides the sweetness and a creaminess that is typical of naturally-cleaned coffee beans. So, if you are looking for a sweeter and less intensce coffee taste, the natural is probably a better choice.

Once the coffee beans are dry, they have to go through a threshing process where the outer skin of the seed is removed from the seed. Once this has been done, the coffee beans can be roasted.