Coffee is a Fermented Beverage — Fermentation and Terroir in a Post Craft Beer World
Traditional coffee is natural fermentation. It is a saison or wild beer. It is real cider or perry. It is low-intervention winemaking.
Post-harvest, coffee cherries are allowed to ferment in controlled conditions during the drying process and this fermentation is influenced primarily by the wild yeasts and bacteria on the cherry skins and in the immediate environment. Coffee flavour, like that of chocolate, is primarily the result of the way roasting transforms flavour compounds created by fermentation and enabled by raw materials developed by climate and skilled agronomy.
The choice of coffee varietal is rarely a deliberate one, and is often a legacy crop that has proved suited to local climate or resistant to regional pests or diseases. Coffee processing (the drying and removal of fruit pulp from around the coffee seed) also generally uses traditional methods that are often influenced by climate or availability of processing facilities. For example: where available clean drinking water is scarce, it is rare to find farmers choosing to use it to wash their coffee.
The cumulative effect is that coffee has evolved an acute sense of place—you might even call it ‘terroir’—that changed very little during the 20th century. Like the wine industry, we are used to engaging with customers in terms of place, of altitude and soil. We talk about classic terroir driven flavour profiles such as chocolatey, nutty Brazilian or bright, blackcurranty Kenyan. It’s one of the main ways coffee is categorised and it is crucial to the way many consumers navigate the vast choice of coffees now available. This has a certain historic and romantic appeal that would be recognised by the more traditional end of the wine industry, but it in some ways can be seen as restrictive; discouraging innovation and limiting the potential of certain origins.
Brazil, for example, is an agricultural powerhouse. Its large, low-altitude farms produce affordable, clean and balanced coffees ideal for the commercial market. However, in the more quality driven 21st century, specialty coffee market these coffees are often overlooked and undervalued due to their lack of sensory complexity. In order to produce more valuable and more desirable coffees farmers have turned to fermentation techniques to develop acidity and fruit complexity in an origin that traditionally pitched its coffees on balance and simplicity. These are often delicious and, to my palate, far more interesting than their flat and wheaty predecessors. But they often don’t taste very ‘Brazilian.’
Illustrations by Laurel Molly
As a terroir-driven drink—meaning its flavour is driven as much by environmental factors as it is by agricultural ones—coffee is changing in the face of a rapidly industrialising world with an unpredictable climate. Many of the best coffee farms in Kenya have been swallowed up by the expansion of its capital city, Nairobi, and have either been sold off for development or have lost their classic flavour profiles. In part this is driven by the loss of biodiversity and changing microflora (wild yeasts, bacteria, etc.) Although the traditional ‘double-washed’ (meaning that after the second fermentation, the beans are washed for an additional time) processing methods deployed by Kenyan producers have at least as much of an impact on flavour as its terroir does, the result is still that this coffee has a strong sense of place.
““I cup Kenyan coffees every year hoping and praying for one more blackcurrant bomb. It never comes.””
I remember the first time I encountered the vivid lip-smacking Ribena character of my first good Kenyan coffee and being simultaneously struck by both its deliciousness and the uncanniness of its fruit character. This is now such a distant memory that I wonder whether it is some kind of collective mania caused by too many years and too much caffeine. Damian Blackburn—the director and coffee buyer at my employer, Marsden’s Dark Woods Coffee—and I cup Kenyan coffees every year hoping and praying for one more blackcurrant bomb. It never comes.
Kenyan coffee is still great. It still shocks and delights with its dance of tart fruit and tea-like crispness but it's, well, different. Terroir, place and tradition are a double-edged sword. How do we learn to equally value coffees that don’t delight the fruit and ferment hungry modern speciality palate or keep celebrating origins that no longer seem to produce the flavour profiles that defined them?
Let's compare coffee to beer for a moment. Thanks to technical progression and innovation, beer eventually moved from wild, and often spontaneously fermented beers into the development of predictable, regional styles more than a century ago. Local availability of hops, water chemistry and historical or cultural behaviours such as long-term storage or exportation over increasing distance led to the emergence of distinct beer styles that eventually, through commercial necessity, became detached from their sense of place. We now talk about Burton ales, West Coast IPAs, Australian pales, and Belgian tripels with little expectation that these beers are still produced in their place of inception. They cease to become terroir driven and become process driven; itinerant and nomadic, freed from their sense of place.
Commercially these cruder stylistic signifiers often take precedence and the styles risk falling into cliché, and are then at the mercy of potentially short-lived fads and fashions. See the demise in popularity of the West Coast IPA in favour of the fun and fruit driven New England styles as one example. Sweet, fruity and big is now the dominant preference in most drink scenes once the niche interest crosses over into full-fledged commercial fad (see also: gin, wine, cider, rum) and coffee is heading in the same direction. One clear inspiration from the craft beer world is that of co-fermentation or “infused” coffees.
A good example of this would be El Placer, a bold and intensely fruit-forward coffee produced by Sebastian Ramirez, who owns and runs a coffee farm based in the Columbian municipality of Calarcá. This coffee undergoes a 120 hour carbonic honey process—where only some of the fruit surrounding the bean is removed before drying, allowing some of the sugar from the fruit to be absorbed by the bean—but also sees the addition of dehydrated, yellow fruits and fruit glucose before an additional 72 hours of fermentation. Once roasted, this produces a coffee packed with flavours of ripe pink grapefruit and fresh lemon zest. It’s absolutely delicious, but it doesn’t taste a lot like what you might think of as ‘coffee’.
As coffee leans more heavily on processing innovation we see more like the above occurring: coffees that belie their origin, eschewing the subtleties of varietal and terroir for often cartoonish, technicolour profiles. A new audience of consumers who demand bigger, bolder and wilder flavours have already radically reshaped the acceptable range of sensory character in our cups.
Fundamentally, for me at least, flavour is fun, and I have always been fascinated by it. There is still a point at which a good coffee is perceptible under layers of fruit or ferment and although I’ve had more bad than good. But the good ones, like El Placer, remind me how exciting it is to have your taste buds, and your perceptions, twisted into new and unexpected shapes.
Coffee is undergoing a moment of self-analysis as it wrestles with similar questions to those of a changing beer industry. The creation and subsequent popularity of specialty coffee has broadly reinvigorated a tired and stepped-on industry in much the same way as the craft beer movement has in the UK over the past two decades. Consumers have got the memos about sustainability, watched the YouTube videos on brewing methods and are putting their money where their collective mouths are in support of the explosion of regional quality focussed roasteries. We now inhabit a very different commercial landscape to the one from a decade ago when we first fired up our 1950’s German drum roaster at Dark Woods. One where the only frontier is flavour.
