Culturing and Quality Coffees

Updated: Nov 28

With respect to fermentation and its different techniques, it is important to highlight that in some places such as Colombia, a great variety of experiments with fermented coffees are already beginning to be carried out.


Taking into account that the most common in the fermentation of coffee is what is known as spontaneous fermentation, which is about leaving the coffee cherry in contact with the external organisms of the fermentation, without interfering in the process, thus obtaining gains in the creation of new flavors as well as added values. In addition to this, it is possible to obtain differentiated and specialty coffees.


Talking about culturing or infused coffees is a relatively young, complex, and controversial topic that dates back to more or less the year 2015 with research on the ways and processes of fermenting coffee.


Coffee fermentation is not only a fashionable topic within the coffee industry but the secret behind the quality of a cup of excellence. Coffee lovers have decided to throw away the old myths surrounding the traditional coffee fermentation process and try new methodologies of controlled fermentation.


When defining the concept of culturing there are two different positions:

  • One relates to the process that takes place during fermentation, adding yeasts or microorganisms that enhance the coffee.

  • The other point refers to the use of fruits or spices during the fermentation process, for example, in cherry coffee, in the drying or immersion process of green coffee beans.


In both cases, what they have in common is the search for new flavors and attributes in the cup, in this way, they are obtaining differentiated cups of the highest quality with sweet and fruity accents and aromas, very much appreciated by consumers. But in order to understand what we are talking about, it is necessary to know what the coffee fermentation process consists of and the different ways to carry it out. Traditionally, coffee has been processed using three methods: washed, natural, and honey processing. However, in recent years we have witnessed the appearance of some non-conventional and alternative processing techniques.


Now, the producers that dare to use processes such as culturing are characterized by their rigorousness and the knowledge that they have of their cultivation, their varieties, and the place where they are located, among other factors that contribute to the final result in the cup.


For those who are not familiar with the coffee fermentation process, here is a quick summary:


Coffee fermentation is driven by enzymes found naturally in the coffee cherry, while yeasts and bacteria break down the sugars in the mucilage. Specifically, there are thousands of species of yeasts and bacteria living on fruit, flowers, soil and even in the air. These different microorganisms thrive in different conditions, such as in warm or cold temperatures and in anaerobic or aerobic environments. Some are considered negative, while others are considered positive. Due to these differences, the way in which we ferment coffees in Colombia will differ from how we would do it in Ethiopia, this is due to the fact that we must take into account the different climates and conditions. According to the norms of the organization, microorganisms that do not form part of the microflora should also be considered as processing aids.


Control points for a correct controlled fermentation of coffee:


If a coffee grower wants to obtain high-quality cups of coffee through controlled fermentation processes, he/she should pay attention and apply the following control points:


  • 80% of the cherries harvested should be ripe berries: This ensures a higher mucilage content with higher sugar content.

  • The water used for fermentation must be of good quality and with a pH between 6 and 8. Dirty water confers dirty flavors to coffee cherries.

  • The water should be spring water and not rainwater: Rainwater is water with a very low mineral load. When in contact with the coffee it extracts minerals from the cherries and prevents the development of certain desirable flavors.

  • The ambient temperature should remain below 20°C during the fermentation process.

  • The fermentation time should be determined according to the ambient temperature where the farm is located.

  • The fermentation time should not exceed 42 hours.

  • Washing: The fermented coffee should be washed with good quality water. Between 2 and 4 washes should be done according to the cup profile that is desired: To obtain coffees with intense flavors, sweet, fruity, and tartaric acidity, one or two soft washes should be done. To obtain much smoother cups with caramel notes, 4 washes should be made before drying the coffee.

  • Dry the coffee immediately after washing it in layers of a maximum thickness of 4 cm.

  • The processes of controlled fermentation in Arabica coffee varietals such as Bourbon, Geisha, Tabi, or Maragogipe, provide better cups than genetically improved coffee varieties.


Thus, setting goals is fundamental for the success of the process, and achieving yields. Culturing can elevate the natural flavors of the bean, creating contrasts between the natural flavor of the coffee and the flavors generated by the work of the producer.


It should be emphasized that there are many ways of doing this, but there is no single recipe. It should be emphasized that the producers that begin with these processes make an investment, research, and development that are nurtured over time.


In turn, this immediately raises other questions:

What should be considered infused coffee? What about the addition of fruit during or after fermentation? Or the storage of green coffee in barrels?


In light of the fact that infused coffee beverages are often an easy gateway for consumers to learn more about specialty coffee, in fact, there are several benefits that infused coffees can have for both producers and consumers:


Producers who grow lower-quality coffee, which would otherwise command lower prices, can add value through infusion.

Producers who grow fruits, flowers, or herbs on their farm can add value to their crop through infusion, and become more sustainable with intercropping.

Reaching new consumer segments can increase the size of the global specialty coffee market and get more people to drink it.

Infused coffee can also introduce new and different flavors to markets that might not otherwise be open to coffee. Many people start drinking coffee with sugar, sweeteners, or syrups, but infusion gives us another option.

Infused coffees can work well as a component of alcoholic or non-alcoholic cocktails.


Now, what coffee can be considered infused coffee?


It all boils down to the addition of ingredients and aromas that can be essential oils, spices, acids, herbs, fruits, vegetables, or any other ingredient that ends up in the final cup once extracted, considering that it can happen during fermentation, in the drying patios, in the cellar or storage, or in aromatic barrels.


However, it is not only that coffee has to undergo an infusion process when it is green, it can be infused after roasting or after grinding. For example, if we add a rose water aromatizer to the coffee during any stage of the preparation and then taste the rose water in the final coffee, it can be considered aromatized or infused. In the same way, if we add tartaric acid and we verify that the tartaric acidity is present in the final notes of the coffee, it would be an infused coffee.


So, we can detect these factors by the aroma compounds that are present, by the components in the oil matrix, or by both. Any addition of flavorings during fermentation that directly transfers to the aromatic compounds of the green coffee survives roasting and ends up in the cup should be considered an infusion.


Time will tell how far culturing can go. For the moment, the limits seem to be wide, and the opportunities are very great for producers with creativity and discipline.

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