Post-harvest processing is one of the most important steps in the coffee supply chain. Not only do these practices preserve (or improve) coffee quality, they can also enhance certain flavour characteristics – or even create new ones altogether.

Historically, the wider coffee industry has focused on what we might refer to as the “big three” processing methods: natural, washed, and honey. In recent years, however, we have seen more and more producers deviate from these “traditional” methods, which often include different and diverse levels of fermentation. In turn, these more experimental techniques are now redefining the way we talk about coffee processing. 

To learn more, I spoke to two pioneering specialty coffee producers: Felipe Sardi, co-founder of La Palma y El Tucan, and Jorge Hernán Castro Molina, Production and Sales Director at Inmaculada Coffee Farms. 

You may also like our article exploring trends in experimental processing.

Traditional vs. experimental

When we talk about experimental coffee processing, we often refer to techniques which deviate from the widely accepted and more formalised protocols for washed, natural, and honey processes. But it’s a little more complicated than that.

Felipe believes looking at the unique history of individual coffee-producing countries is an important starting point.

Using Colombia, as an example, he says: “For over a hundred years, we’ve been washing arabica varieties for between 18 to 24 hours in tanks,” – a standard approach in the country’s coffee sector.

“In the case of Colombia, I think the baseline is clear,” he adds. “So anywhere that producers start deviating from that point could be though of as innovation or challenging the status quo.”

This rule could also apply to other producing countries, such as:

• Brazil and Ethiopia, where many producers opt for natural processing methods
• Costa Rica, where honey processing is vastly popular
• Kenya, where the washed process has been the standard for decades

The role of fermentation

To most consumers and industry professionals, experimental processing usually implies some kind of extended fermentation. It’s worth noting, however, that all coffee is fermented at some point during processing. Ultimately, what matters is the duration and type of fermentation, as well as the conditions under which it happens.

Felipe tells me that one of La Palma y El Tucan’s unique fermentation processes was the result of an accident when a few bags of cherries were left behind a door. The cherries began to ferment in a way that Felipe now describes as “anaerobic pre-fermentation”.

“From there we started to improvise in a more artisanal way,” he adds. He explains that the farm partnered with the National University of Colombia’s biochemistry lab and two private labs in Bogotá to conduct further research.

Jorge says that Inmaculada Coffee Farms is also committed to understanding the science behind fermentation – a process which began around 11 years ago. Inmaculada’s experiments have ranged from different lengths of fermentation to temperature-controlled fermentations, with the overall goal to understand how different variables affect flavour.

Moreover, all of the farm’s coffee is natural, which in the context of Colombia is a deviation from traditional processing methods.

“The factors you need to change are how rigorously you do things and to understand why you do things,” he says. “Five years ago, we were producing natural aerobic coffees, but what we are doing now is sharpening and polishing our processing methods.”

Re-defining experimental processing

In just a few short years, experimental processing in specialty coffee has evolved from accidental fermentation to highly-controlled conditions. Notably, this shift has also occurred alongside a movement in the wider food and drink industry where fermented flavours are becoming more popular across many different cuisines and cultures – which has undoubtedly influenced specialty coffee consumers’ preferences.

“I love it,” Felipe says. “If you follow what happened in the craft beer industry or the natural wine movement, I think these trends will remain. The spike in popularity is temporary, I’m sure about that, but I believe demand will continue to grow.”

The impact of more novel and advanced processing methods has been felt across the entire coffee supply chain over the past few years. So with more and more research undertaken to understand these techniques, do we have a clear definition of them – or are we even redefining them in a sense?

Generally speaking, the answer still remains unclear. But Jorge explains that no matter how an individual or farm defines their approach, it’s still important to try to showcase terroir and inherent characteristics.

He uses Gesha as a specific example: “We process this variety as ‘plain natural’ because anaerobic fermentation results in very fruity profiles. You don’t always want those types of flavours in a Gesha – customers usually expect very floral and elegant tasting notes, which is what we want to showcase. 

“Meanwhile, varieties and species like Sudan Rume, Laurina, or eugenioides often better suit anaerobic fermentation, compared to natural, washed, or honey processing, for instance,” he adds.

Have experimental processing methods even become more mainstream?

Although the prevalence of processing methods such as anaerobic fermentation, lactic fermentation, and carbonic maceration still remains relatively small in the context of the wider coffee industry, their presence is notably increasing. Could we therefore be reaching a point where these techniques could even become mainstream?

Given that the Specialty Coffee Association’s Green Coffee Course module now covers controlled fermentation, this is clearly a sign that times are changing – and fermented flavours are no longer seen to be strictly defects.

At the same time, however, “mainstream” could be too strong of a term. But it certainly appears that wider acceptance of and encouragement to implement novel and advanced processing methods has opened doors to further experimentation, such as thermal shock and infused coffees. 

The former involves controlling the temperature of different fermentations to influence the final cup profile. The latter, meanwhile, is when producers add ingredients such as fruit pulp, aged beans, and essential oils to coffee to infuse new flavours.

Infused coffees in particular have caused some division between producers and other industry professionals, especially in regards to whether they should be considered experimentally processed or something else entirely.

“We want to highlight variety genetics and terroir, so we don’t add any yeast, infusion ingredients, or artificial flavours,” Jorge says. 

This argument does, however, raise an interesting discussion about whether we don’t always have to define experimental processing methods by exerting rigorous control over different variables. Instead, producers may be able to make more holistic choices which best suit their needs.

So what does this mean for the industry?

There’s no denying that specialty coffee has embraced experimental processing techniques. But with standards and protocols evolving and changing, what are some of the key considerations we need to keep in mind?

With regards to infused and flavoured coffees in particular, Jorge flags some ethical concerns about transparency with labelling.

“If you sell infused or flavoured coffee and neglect to clearly inform the customer, it harms specialty coffee,” he says. “[In my opinion], when farms add ingredients to create new flavours during experimental processing, they undo all of the effort put in during production because they are not accurately portraying the challenges behind growing coffee.”

Issues are not always just limited to ethics, however. If producers don’t tightly control variables, coffees can easily over-ferment. This leads to undesirable off-flavours like sour milk, rotten fruit, or low-quality wine.

As such, many farmers who carry out experimental processing do so in smaller batches, which allows them to change and control variables more effectively.

Weighing up the pros and cons

Not all producers have the capacity or resources to carry out experimental processing methods. But for those that do, the risk can still be high. Over or poor fermentation can lead to lower yields, not to mention the increased costs associated with these types of processing techniques.

“We should be very cautious about thinking these methods are easy for most producers,” Felipe believes. “In fact, it’s very dangerous to promote it without acknowledging the level of risk.”

One way that producers can absorb less risk is by partnering with roasters.

“I’ve worked with a few roasters in Panama who want to be more hands on with processing,” he adds. “They want to inoculate with yeasts, change temperatures, and use the tanks themselves – and pay an amount regardless of the result. 

“As a producer, I say of course, let’s do this together,” he concludes. “I think with these sorts of incentives, we can see more of these great tasting coffees with different sensory profiles.”

With experimentally processed coffees continuing to command high prices – and increasingly helping roasteries and baristas win the most prestigious industry competitions – their popularity is sure to grow. With this in mind, it’s important that the risk for producers is fairly minimised.

However we may define them, whether as an industry or as individuals, experimental processing methods are leaving their mark on specialty coffee. And the future seems promising.

Enjoyed this? Then read our article on how experimental processing can help producers overcome challenges.

Photo credits: La Palma Y El Tucan

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