Coffee processing methods have a significant effect on flavour. Recently, Dario and I travelled to Volcan Azul in Costa Rica. Alejo’s coffees are known for their exceptionally clean and clear flavour profiles. We were honoured to witness the production of some of Alejo’s incredible coffees and we look forward to another exceptional season of Volcan Azul coffees in 2023. All the photos in this post will be from our trip to Volcan Azul.
Coffee processing (at the wet mill) is essentially a combination of removing the fruit from the seed (or “bean”, as we’ve all come to know it) and then drying. The differences are in the degree to which the fruit is removed, when it is removed and then the variances in drying time, drying technique and then the coffee moves into the dry mill.
The processing methods I’ll discuss in this post are washed, honey and natural processing.
A “washed coffee” is one that has had all the parts of the cherry/fruit removed from it before drying. If you read “washed” on a bag of coffee, this is the processing method the coffee has undergone.
The bright red cherry flesh that surrounds the coffee beans is made up of multiple layers. The first is the pulp, the outer skin and then surrounding the bean is the mucilage.
In the washed process, all of these layers are removed from the beans before they are dried.
Washed coffees are arguably the “purest” of the processing methods because what you taste in the cup is dependent on varietal and terroir, without any additional complexity from the cherry flesh, if the washing is done properly. There is no fermentation of the cherry during drying, which cannot always be completely controlled, washed coffees are the most consistent to produce. The lack of uncontrollable variables means that each lot can come out exactly the same after processing.
Washed coffees are often described as clean and balanced.
In honey processing, only the pulp is removed from the bean and the coffee is dried with the mucilage still covering it.
After some time has passed in the drying process the mucilage begins to break down into a dark, thick and sticky liquid, similar to honey – this is where this processing method gets it name.
Coffees that are honey processed are often put through a depulper before being dried and only a small amount of the mucilage will be removed. Depending on how much mucilage is removed, the coffee will either be a white, yellow, gold, red or black honey.
Alejo told us that the philosophies around honey processed coffees are often different from farmer to farmer. The processing method is largely open to interpretation and allows for the farmer to decide the degree to which they depulp their coffees in order to get the best results. All of which will fall under the method of “honey processed”.
Each layer of the cherry flesh contributes flavour to the bean. The bright red pulp is sweet and juicy. Cascara tea is this dried flesh made into a tea. If you have ever had cascara tea, you are familiar with the deep, natural sweetness of the cherry.
Natural processing is when the mucilage and pulp are left on the beans when they are dried. Leaving the flesh on the coffee during drying means that as the bean dries out and breaks down, the sweet and complex flavours of the fermenting cherry can penetrate into the bean.
It is crucial that the fermentation is controlled during the drying process, as the natural processing method is likely to result in fermented flavours. When dealing with any fermentation, there are many factors that need to be considered. Temperature, time, light exposure, agitation and pressure all affect the way that the cherry ferments and therefore the flavour that is left in the bean.
Naturally processed coffees are often bold with fermented flavours.
Want to read more about coffee processing?
Perfect Daily Grind, How to Improve Quality When Processing Washed Coffees
Perfect Daily Grind: Processing 101: What Is Washed Coffee & Why Is It So Popular?
Perfect Daily Grind: How can controlled fermentation processing methods enhance coffee flavour and quality?
Perfect Daily Grind: Coffee Processing: Exploring Naturals, Pulped Naturals, & Honeys