Thermal Shock? Ice Processing? Carbonic Maceration? These are all terms you might have heard thrown about recently. That’s because ‘experimental’ is the word on everyone’s lips at the moment when it comes to processing. But what are all these exotic processing methods? Let's take a look at some of the most common experimental process, and a couple that are a little bit more unique.
What is Experimental Processing?
Experimental processing is the term given to a processing method outwith the traditional methods, Washed, Natural & Honey. These processes generally involve forms of extended fermentation that add layers of complex flavours to the profile of the coffee. Often the processes are adapted from methods out with the coffee industry, such as wine making. With this experimentation, the farmer also adds a layer of risk to their crop. Because these processes are untested, the farmer has no way of knowing if the coffee will score highly, or if the crop will spoil, resulting in great financial impact to the farmer. But as the appetite for these coffee grows amongst coffee drinkers around the world, the more boundaries farmers are pushing to achieve the most unique and funky cup of coffee.
Now that you know the basics, let’s take a deep dive into some of the most popular experimental processes.
Anaerobic Fermentation
All coffee undergoes some form of fermentation during processing. What separates Anaerobic fermentation from basic fermentation, is the removal of oxygen from the equation. To carry out an Anaerobic Fermentation, intact or de-pulped coffee cherries are sealed in containers with water for a pre-determined length of time before they are dried. This process rapidly changes the flavour of the coffee, leading to more complex flavours than traditional fermentation.
Thermal Shock
We know a thing or two about this process thanks to the incredible coffee we currently have from Yenni Esperanza. The coffee is picked at 95% maturity and then washed using ozonated water and ultraviolet light. The coffee then undergoes an anaerobic fermentation in a steel tank for 48 hours at 18°C, before being pulped, and then undergoing a further 48-hour anaerobic fermentation at 21°C. Finally the coffee undergoes a heat shock to eliminate any micro-organisms and is then machine dried by air circulation for 12-28 hours at 34°C.
Carbonic Maceration
Taking it's name from a wine making process common in the Beaujolais region of France, this process first hit the spotlight in 2015 when Saša Šestić used it in his World Barista Championship routine. For this process, the coffee cherry is places inside a sealed container before being flushed with carbon dioxide. Anaerobic Fermentation & Carbonic Maceration are both quite similar in the sense that they are both low oxygen environments, the only difference is that with Carbonic Maceration, the initial fermentation must take place inside the cherry, with the addition of carbon dioxide.
Ice Fermentation
Another experimental process that we're familiar with thanks to the sensational coffee from Jairo Arcila. Ice fermentation is a relatively new, experimental processing method that was developed by coffee producer Jairo Arcila and his sons and co-owners of Cofinet, Felipe and Carlos Arcila. This coffee was exposed to a dry aerobic fermentation of 24 hours. This fermentation begins as soon as a coffee is picked, due to the presence of water, sugar, bacteria, and yeast. Leaving the fruit on the coffee during this phase allows for the sugars and acids in the coffees mucilage to convert into different sugars, acids, CO2, ethyl alcohol, and other compounds. This imparts sweet and fruity flavours on the coffee. The coffee is then placed inside grainpro bags for 50 hours, maintaining a temperature below 22 degrees while fermentation continues. Afterwards, the coffee is frozen for 72 hours, before being placed on raised beds below 35 degrees to thaw and dry until ideal moisture content is achieved.
So there you have it. An intro into the complex world of experimental processing. This is by no means a comprehensive list, with innovation moving rapidly, there is a constant flow of new processing methods making their way to market with each new harvest. One thing is for sure, there's never been a more exciting time to be a fan of specialty coffee.
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