Modern technology has transformed the usual techniques for the treatment and processing of coffee. An example of this is the numerous changes suffered in the fermentation method applied to remove the mucilage surrounding the grain.
One of the fermentation techniques that continues in trend in the wonderful coffee world is carbonic maceration, a method applied in the wine industry. Still, since 2015, its use has been extended to coffee to improve the beans’ attributes.
There are many other forms of coffee fermentation, and it will depend on what the producer wants to obtain. For example, the submerged fermentation technique is when water is added to the pulped coffee. Different systems are also used to apply fermentation; these can be open or closed, static or agitated, among others.
The carbonic maceration process is currently employed to add value to elite coffee and incorporates novel flavors and sweetness that favor the cup profile.
Fermentation is a controlled process in which a chemical reaction is provoked by different natural components and microorganisms, mixing the water and sugars found in the coffee cherry. Microorganisms such as bacteria, yeasts, and many others break down sugars into acids or alcohols.
Find out all about carbonic maceration
Carbonic maceration provides a different profile at the final rate. Coffee becomes a more aromatic product, with sweet notes and body. The process is applied as follows:
- The whole coffee cherry is placed in a closed and airtight container.
- Oxygen is removed from the container, and carbon dioxide (CO2) is added.
The function of carbon dioxide is to slow down the process of sugar breakdown and prolong fermentation, causing an increase of pressure in the environment. It is recommended to use a valve to release pressure without oxygen entering the system.
Unlike open fermentation, the absence of oxygen during the maceration process allows bacteria proliferation and limits the reproduction of yeasts. Bacteria break down sugars into carbon dioxide and alcohol.
Maceration is an advantageous technique that reduces the long periods of fermentation that cause vinegar notes, allowing acidity levels to progress slowly. For this reason, there is less acidity of alcohol.
One of the peculiarities of carbonic maceration is that fermentation occurs within the coffee cherries’ cellular structure. The final products are pleasant to the palate, and you can appreciate the variety of flavors in the grain. For example, low temperatures (4-8 °C) improve acidity, while higher temperatures (18-20 °C) improve sweetness.
Washed and natural coffees
In the washed carbonic maceration, the ripe cherries are harvested manually, sorted, pulped, and placed in an airtight container. Instead, in natural carbonic maceration, the cherries are introduced into airtight tanks, processed, and finally dried in African beds until the appropriate humidity is achieved.
It is a controlled procedure that requires several conditions to have successful results. Temperature and fermentation time are also essential to give aroma and good flavor to beans.