4.5 Minute Read
Jose Pastor Huerta
PECA Coordinator Nicaragua
During the post-harvest process for washed coffees, beans pass through a series of steps that are vital to maintaining the quality of the product. One of the most important stages is the fermentation process, where sugars in the mucilage of the de-pulped coffee are broken down by yeast and bacteria, allowing the mucilage to be washed off with much greater ease.
Many institutions recommend that coffee growers use a variety of tools to identify the perfect moment to stop fermentation and proceed to washing. There are different traditional methods to achieve this, including by touch, or by permeating the surface of the coffee fermenting in the tank with an object to see if the beans collapse in on themselves or maintain a divot. There are many factors that can impact fermentations times, but weather is one of the most important variables. If the temperature is cold during harvest, the fermentation process would customarily take between 12 and 14 hours. Cherries are de-pulped between 4 and 6 pm, and then the washing process is performed the following morning from 5 to 7.
When Caravela began working in Nicaragua, the initial recommendations from our PECA team were to extend fermentation times from around 12 hours to between 24 and 40 hours, depending on the temperature. Coffee producers were initially reluctant to make these changes, having always been told that lighter colored parchment would be considered higher quality by exporters, while parchment possessing a yellowish hue due to prolonged fermentation would be perceived as less valuable. However, many coffee growers started to adopt these new techniques recommended by our PECA team, with very interesting results.
We started carrying out experiments with different fermentation times, working with producers on their farms. After the harvest, we analyzed the quality of each coffee in the experiment with respect to consistency, complexity, and scoring. We examined trends and relationships between fermentation times and quality scores and used these analytics to provide recommendations to coffee growers.
Today, most coffee growers that we work with in Nicaragua are carrying out a fermentation processes of more than 24 hours. We continue encouraging them to experiment to identify the ideal fermentation time based on their specific climatic and farm conditions.
Conducting fermentation experiments in Nicaragua has impacted coffee growers in many ways. It has deepened producer understanding and knowledge. Although these famers have produced coffee for many years, a focus on innovation and quality is new territory for them as they switch from more conventional techniques. Experiencing positive results has stimulated their interest and curiosity. Today, coffee growers are even more open to experimentation, and understand that quality improvement is a matter of testing, trying, making mistakes and learning from them.
Along with acquiring new knowledge, growers have also seen increased economic value as their quality grades have improved, which directly raises the prices they receive for their coffee. We have seen notable changes in the profile of Nicaraguan coffees over time. With longer fermentation times, Nicaraguan coffees have evolved to be demonstrably fruitier, while possessing a fuller body and more consistent flavors.
Farmers who have improved their quality are now more competitive in the specialty market, automatically positioning themselves for the opportunity to be recognized at the international level. These coffees now hold their own against other outstanding coffees grown in Colombia, Guatemala, and other origins that can boast long-term acknowledgement of their quality. Not only is the coffee being noticed, but coffee growers are themselves receiving the accolades that they deserve for being innovative and proactive.
These experiments on Nicaraguan coffee farms allowed farmers to improve their quality compared to previous years. Harvest after harvest, farmers are more interested in carrying out experiments and different processing methods.
Feedback from our PECA and QC team has been of vital importance to guarantee the success of this project. We offered coffee growers feedback through meetings and talks in every region where we work. Coffee growers have now changed their beliefs that low fermentation times mean better quality.
Over the course of this project, we conducted fermentation in containers made of different materials, such as concrete or ceramic tanks, plastic sacks, and plastic tubs and barrels. Based on the extended fermentation experiments, we saw better results in coffees fermented in plastic barrels. This happens because the temperature of the coffee mass is homogeneous throughout the whole fermentation process as these plastic barrels contain the coffee beans tightly together and tend to be smaller in size compared to tanks. Due to this new finding, coffee producers have been looking to replace their fermentation tanks.
Based on the data that we collected from the experiments, matched with the observations on the farms, we can assert that there is a trend demonstrating that the best cupping scores came from coffees that were fermented for more than 24 hours. We did an analysis of all the coffees delivered to us during the last harvest in Nicaragua and registered their fermentation times, which were then compared to their cupping scores. We could see a direct correlation between these fermentation times and cupping scores. For instance, those coffees that scored an average of 85 points, were only fermented for around 23 hours and those with higher average scores like 87 points, were fermented for around 32 hours.
Fermentations times do affect quality and coffee complexity. However, there are many other factors that can influence the coffee and its shelf life. For instance, tree management - including nutrition, fertilization, and plague and disease control - are important variables that affect quality. For this reason, some of the experiments didn’t always yield the expected result.
Many producers experienced the benefits of longer fermentation times and are now implementing these different techniques to achieve better quality. Our QC team, in addition to our customers, have also seen an improvement in the Nicaraguan coffees that we select and sell. These coffees with new and more complex profiles have opened a huge door to the specialty coffee market, with the opportunity to receive a wider variety of coffees from Nicaragua.
Fermentation time is an important variable that coffee growers can manipulate to better highlight the attributes of their coffee. However, there must be good phytosanitary and tree nutrition management for the effects of this increased fermentation time to be effective.
In the future, we plan to continue conducting fermentation experiments but look forward to tweaking some of the variables. For example, we plan to ferment in different environments, such as open or closed, continuous fermentation or split, controlled temperatures and control mass volumes. The results of these will hopefully provide producers with even more detailed fermentation information, allowing them to improve quality harvest after harvest.