Coffee Fermentation with Fruits: A New Trend in Specialty Coffee

Coffee fermentation with fruits is a new trend in the specialty coffee market. Coffee producers are innovating in production and processing to meet the demand for exotic flavor profiles and high cupping scores. Fermentation naturally starts occurring just after a coffee cherry is picked, and sometimes before, if the humidity is high enough. It is when microorganisms, like yeasts and bacteria, in and around the cherries interact with the sugars in the mucilage, the sticky layer between the seed and the pulp, and break them down into simpler molecules, producing liquid products and volatile compounds. The microbes and the chemical reactions they induce can affect the chemical compositions of the coffee beans and thereby their cupping quality.

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Recent experiments have led some producers to include fruit when fermenting coffee. One such example is where cherries are fermented in a sealed, airtight tank for anaerobic fermentation along with a pre-established percentage of whole fruits or extracts, often sugar cane juice or citrus fruits. This mixture is then fermented in the tank for a predetermined period of time. The tank’s sealed environment allows for the buildup of carbon dioxide, which creates an anaerobic environment that encourages the growth of specific microorganisms that produce unique flavor attributes and sensory characteristics between coffee brews.

Controlling fermentation is still a relatively new and under-researched part of coffee processing. Scientists are just beginning to explore how it impacts a coffee’s final cup profile. Many feel that more research is needed on fermentation in general, before fruit fermentation can be fully understood. However, the growing demand for fermented coffee means that it can fetch a high price, potentially benefiting farmers. And the process by which the beans are prepared requires much less water than traditional methods, making it more environmentally friendly.

This article will explore the process of coffee fermentation with fruits, its benefits, and how it can be done. It will also discuss the role of microbes in coffee fermentation and their impact on coffee quality. Finally, it will provide tips on how to make the best coffee using fermented fruits.

The Process of Coffee Fermentation with Fruits

Fermenting coffee with fruits involves adding whole fruits or extracts to the fermentation tank along with the coffee cherries. The fruits can be any type of fruit, but sugar cane juice and citrus fruits are the most commonly used. The fruits are added to the tank in a pre-established percentage, and the mixture is then fermented in the tank for a predetermined period of time. The sealed environment of the tank allows for the buildup of carbon dioxide, which creates an anaerobic environment that encourages the growth of specific microorganisms that produce unique flavor attributes and sensory characteristics between coffee brews.

The process of coffee fermentation with fruits can be broken down into the following steps:

Harvesting: Coffee cherries are harvested when they are ripe and red.
Sorting: The cherries are sorted to remove any damaged or unripe cherries.
Depulping: The outer skin of the cherry is removed, leaving the mucilage intact.
Fermentation: The cherries are placed in a sealed, airtight tank along with a pre-established percentage of whole fruits or extracts, often sugar cane juice or citrus fruits. The mixture is then fermented in the tank for a predetermined period of time.
Washing: The fermented cherries are washed to remove any remaining mucilage.
Drying: The washed cherries are dried in the sun or using a mechanical dryer.
Roasting: The dried cherries are roasted to produce coffee beans.

Benefits of Coffee Fermentation with Fruits

Unique flavor profile: Fermenting coffee with fruits can produce unique flavor attributes and sensory characteristics between coffee brews. The fruits can add sweetness, acidity, and complexity to the coffee.
High cupping scores: Fermented coffee beans can fetch a high price, potentially benefiting farmers. The growing demand for fermented coffee means that it can be sold at a premium price.
Environmentally friendly: The process by which the beans are prepared requires much less water than traditional methods, making it more environmentally friendly.

How to Ferment Coffee with Fruits

Fermenting coffee with fruits can be done using the following steps:

Harvest ripe coffee cherries.
Sort the cherries to remove any damaged or unripe cherries.
Depulp the cherries, leaving the mucilage intact.
Add a pre-established percentage of whole fruits or extracts, often sugar cane juice or citrus fruits, to the fermentation tank.
Seal the tank and ferment the mixture for a predetermined period of time.
Wash the fermented cherries to remove any remaining mucilage.
Dry the washed cherries in the sun or using a mechanical dryer.
Roast the dried cherries to produce coffee beans.

The Role of Microbes in Coffee Fermentation with Fruits

Microbes play a crucial role in coffee fermentation with fruits. They interact with the sugars in the mucilage and break them down into simpler molecules, producing liquid products and volatile compounds. The microbes and the chemical reactions they induce can affect the chemical compositions of the coffee beans and thereby their cupping quality.The microbes that are involved in coffee fermentation with fruits can be divided into two groups: yeasts and bacteria. Yeasts are responsible for the production of alcohol, while bacteria are responsible for the production of organic acids. The specific types of yeasts and bacteria that are present in the fermentation tank can vary depending on the type of fruit that is used, the temperature of the fermentation, and the duration of the fermentation.

Recent research has shown that the use of specific starter cultures can help to control the fermentation process and produce consistent flavor profiles. Starter cultures are mixtures of specific yeasts and bacteria that are added to the fermentation tank to encourage the growth of specific microorganisms that produce desirable flavor attributes and sensory characteristics.

Tips for Making the Best Coffee Using Fermented Fruits

Use high-quality coffee beans: The quality of the coffee beans is crucial to the final cup profile. Use high-quality coffee beans that have been harvested and processed correctly.
Use fresh fruits: Use fresh fruits that are in season and have been harvested at the peak of ripeness. The quality of the fruit will affect the final cup profile.
Control the fermentation process: The fermentation process should be carefully controlled to produce consistent flavor profiles. Use specific starter cultures to encourage the growth of specific microorganisms that produce desirable flavor attributes and sensory characteristics.
Experiment with different fruits: Experiment with different fruits to find the flavor profile that you prefer. Different fruits can add sweetness, acidity, and complexity to the coffee.
Roast the coffee beans correctly: The coffee beans should be roasted correctly to bring out the unique flavor profile of the fermented fruits. The roast level should be adjusted to suit the flavor profile of the coffee.
Store the coffee beans correctly: The coffee beans should be stored correctly to maintain their flavor profile. Store the beans in an airtight container in a cool, dry place away from light and heat.

Conclusion

Fermenting coffee with fruits is a new trend in the specialty coffee market. It involves adding whole fruits or extracts to the fermentation tank along with the coffee cherries. The fruits can add sweetness, acidity, and complexity to the coffee, producing unique flavor attributes and sensory characteristics between coffee brews. The process of coffee fermentation with fruits is still a relatively new and under-researched part of coffee processing. However, the growing demand for fermented coffee means that it can fetch a high price, potentially benefiting farmers. The process by which the beans are prepared requires much less water than traditional methods, making it more environmentally friendly. By following the tips outlined in this article, you can make the best coffee using fermented fruits and enjoy the unique flavor profile that it offers.