Experimental Coffee Processing Methods

In our previous blog posts, we have explored different coffee processing methods (natural, washed, and honey processing) and how each of these affects the flavour of coffee. 

While these are the primary methods used by coffee producers, some experimental coffee processing methods allow the producers to alter the flavour profile and even improve the quality of the coffee. A couple of these experimental coffee processing methods are carbonic maceration, anaerobic fermentation, and lactic acid fermentation. 

Let’s take a closer look at each of these.

Carbonic Maceration

Carbonic maceration is a fermentation process that was originally used only in winemaking. It was introduced to the world of coffee back in 2015 during the World Barista Championship. 

As you might be able to guess from the name, this involves the use of carbon dioxide to process coffee cherries. The cherries are sealed in airtight containers that are flushed with carbon dioxide to remove oxygen. 

The CO2 breaks down a compound called pectin in the coffee. As a result of the chemical changes that occur, the aroma and flavour are absorbed by the coffee bean. Once the producer is satisfied with the level of fermentation, the coffee can be washed or natural-processed before being dried.

The resulting flavour of coffee is fruity and has similarities to that of wine. You may also notice some floral and earthy-tasting notes. 

An advantage of this method is how it creates products that stand out in the market.

Anaerobic Fermentation

When a coffee producer is trying to craft coffees that have a fruitier flavour profile with a good body, anaerobic fermentation is a method they can use.

In this process, coffee cherries are fermented without allowing any oxygen to be present. And so, the coffee cherries get sealed in tanks or barrels, sometimes for as long as 90 hours.

Since they are processed in an oxygen-free environment, the sugar compounds in the coffee are broken down at a much slower pace, letting it develop a complex flavour.

It is different from aerobic fermentation wherein oxygen is a part of the process and microorganisms break down sugar faster. 

One of the benefits of employing this method is that it can bring in more revenue for coffee producers due to the value of the final product. At the same time, the need for precision during this process means that producers have to pay more attention.

Lactic Acid Fermentation

This method brings down the coffee acidity by controlling the fermentation process and allowing lactic acid to form. As a result, the cup profile offers a clean and smooth taste.

Similar to anaerobic fermentation, coffee cherries are placed in sealed tanks, making sure the cherries are not exposed to oxygen. Such an environment is crucial for the formation of lactic acid bacteria. 

The lower pH levels in the tank encourage certain chemical reactions which affect the flavour profile. It takes over 80 hours to ferment coffee using the lactic acid fermentation method.

Coffees produced using this fermentation process tend to have a velvety mouthfeel with flavour notes of chocolate and butter.

These fermentation steps are a part of the overall coffee processing. In the sense that you can find washed carbonic maceration coffee or even natural-processed anaerobic coffee. 

Experimenting with coffee is not new to the coffee industry. Specialty coffee producers have been trying to improve the value of the coffee they produce by using resources and techniques that create a demand for rare and niche coffee types. 

Processing coffee in such different ways helps increase its value, not only in terms of the price it fetches but also the flavour experience that the customer gets.