Coffee drying in Sumatra

Learning from Sumatras

I’ve been cupping coffee professionally for less than a year. Ken Davids first hired me at Coffee Review last August, given that my background in food and wine writing, as well as in academia, seemed a good enough calling card to dip into the world of coffee. But, of course, in order to properly do this work, I would need to be trained in cupping, the rigorous sensory evaluation of coffee. While I’ve long enjoyed my favorite coffees prepared relatively carefully at home, mostly as pour-overs, I had never turned my attention to coffee in as precise a way as I had learned to focus on wine as a sommelier and wine writer. I quickly came to learn that coffee is at least as complicated as wine and perhaps more nuanced in its sociocultural intersections. This month’s cupping of 27 Sumatras for our July tasting report underscored my first early lessons, as well as opened up a whole new quadrant on the flavor wheel for me.

It’s the Processing

My first attempts at cupping with Ken and Jason Sarley, our resident Q-grader, left me feeling, at turns, confident and completely at a loss. “Yes, I get dark chocolate, orange zest, and an aromatic wood akin to fresh-cut cedar, but where is this floral note the two of you are waxing poetic about?” are the kinds of thoughts I had on a daily basis. “And why do you refer to this coffee’s acidity as ‘brisk,’ as opposed to ‘bright’”? With wine, I was often concerned with grape varieties over all else, as varieties tended to be the greatest predictor of how a wine would ultimately taste, followed by origins with their distinctive terroirs. But with coffee, it seemed almost immediately that processing method was a first-step key to unlocking the mysteries of the end product. Of course it was clear that the impact of tree variety is crucial to understanding coffee, but the ability to approach coffee critically for me seemed to start with an awareness of the influence of processing, or the varied and complex procedures through which the skin and pulp of the fruit are removed from the beans and they are dried.

In my first months at the cupping table, I had the good fortune to experience coffees I’d never have been exposed to if left to my own devices: exotic varieties like Sudan Rume, expensive Panama Geshas, and many natural-process Ethiopias, a penchant for the likes of which, arguably, distinguishes hard-core coffee aficionados from the average coffee- drinker who has developed an affinity for a more narrow range of coffee styles. Dried blueberry? Rye whiskey? These are aromas and flavors I had never associated with my breakfast beverage, yet here they were, plain as day, in my cup. Conversely, I experienced the more familiar wet-processed Colombias and Costa Ricas in terms of previously undetected subtleties: levels and types of sweetness, associations with various fruits and nuts, and degrees of intensity, in both aroma and flavor. And chocolate. Almost always chocolate, whether crisp roasted cacao nib, rich fudge, or one of many variations in between.

Sumatra’s Unique Wet-Hulling Process

The majority of the Sumatras we cupped for this report were wet-processed using a method particularly associated with Sumatra called “wet-hulling” or giling basah in the local Batak languages. Traditional wet processing involves removing the skin and soft pulp of the coffee fruit from the beans via either fermentation and washing (the traditional method) or by machine-scrubbing, in either case leaving the coffee bean encased only in its inner parchment and silver skin as it is dried to roughly 12.5% moisture. The coffee is stored “in parchment” and the dried, crumbly parchment skin is only removed from the beans when they are ready to be shipped. In wet-hulling, however, the parchment skin is removed in the middle of the drying process, when the beans still have a high moisture content, often as high as 40%. Although this small difference between conventional wet-processing and wet-hulling may seem trivial, it appears to result in a striking difference in cup character, promoting an array of aroma/flavor notes that range from outright musty or mildewy in poor quality wet-hulled Sumatras to the engagingly intricate, humus-like sweet tobacco and tropical fruit notes that show up in the very finest wet-hulled Sumatras, seven of which we review this month.

Although the bag copy and websites for some of the Sumatras we cupped used alternate terms for the wet-hulling process—“semi-washed” was the favorite, although “semi-dry” showed up as well—we at Coffee Review understand that the terms semi-washed and semi-dry are best used to describe other processing methods in use in other parts of the coffee world (in Brazil, for example). For us “wet-hulling” or giling basah best describes this unusual Indonesia processing method, and whenever we were able to confirm that this processing method had been used to produce a coffee we reviewed, we applied that term.

Of course, as we often point out at Coffee Review, coffee producers the world over are experimenting with processing methods from other parts of the world that do not reflect traditional local practices. In the case of this month’s 27 Sumatras, in addition to traditional wet-hulled samples, we also cupped two natural-processed samples (beans are dried inside the entire fruit), three conventionally wet-processed samples, and four “honey” processed samples (the skins are removed, but the beans are dried with at least some of the fruit pulp still adhering to them). This last method, called “honey” in Central America, is also sometimes called “semi-washed” in Brazil, adding to the confusion around the latter term.

All Sumatras, All the Time

At any rate, this month’s cupping of Sumatras for our July tasting report deepened my appreciation of processing method as a primary contributor to what a coffee will taste like, and also awakened me to the vast range of possibilities conscientious farmers and mill operators can contribute to the complexity, nuance and distinction of coffees through processing variations.

Before this exercise, which spanned several weeks and 27 coffees, I had cupped only a handful of coffees from Sumatra, the huge, westernmost island of Indonesia, none of them particularly impressive. The positive Sumatra descriptors I first identified included moist pipe tobacco, dried pineapple and a suggestion of spicy smokiness that my co-cuppers deemed not associated with the roast, but with the green bean itself. And so I went into this month’s cupping with a stereotype about Sumatras that was debunked by the depth, range and unequivocal sweetness of the finest of the samples we cupped.

In Coffee Review’s tasting report on wet-hulled Sumatras last year, Ken described Indonesia’s most popular processing method, giling basah or wet-hulling, as often resulting in “elegant earth.” In my wine lexicon, this conjures Cabernet Franc, often described as rustic, savory, herbaceous, and even green-vegetal, descriptors that can be a compliment, or not, depending on the quality of the particular Cab Franc. Many Cab Francs, unblended, are also described as the opposite of “clean:” funky, earthy. Until this cupping, I associated all Sumatras with this deep earthiness, which, in fact, is a bit of a stereotype. Like Cab Francs, many Sumatras express an elegance, to borrow Ken’s term, that transcends the lesser Sumatra coffees I’d casually encountered before.

The Coffees

The most common adjectives the three of us noted in our cupping of the best wet-hulled coffees (seven of the eleven samples reviewed here were wet-hulled, ranging in score from 92 to 94) were pipe tobacco, various tropical fruits like mango and coconut, richly savory tamarind and, perhaps the biggest surprise for me, lush floral notes we associated with lilac and honeysuckle. Occasionally, fresh humus or decaying moist leaves would appear as descriptors, but in the best of these samples it was always in the context of rich, elegant sweetness.

Tied for the top score of 94 were Korean roaster Crescendo’s Sumatra Black Panther and Klatch Coffee’s Sumatra Lintong Mutu Batak. Both were subtly different but clearly characteristic variations on a Sumatra wet-hulled theme: The Crescendo Black Panther sweet and deep with mango and tobacco tones; the Klatch Lintong Mutu Batak brighter with pungent grapefruit animating the floral and tobacco notes. Among the wet-hulled Sumatras reviewed here at 93, the PT’s Batak Nuali Sumatra was more zesty and savory, and the Panorama “Blue Bianca” more explicit in its sweet earthiness, though still complicated with fruit, tobacco and chocolate. The Taiwan roaster ICC’s Lintong Blue Batak (93) added an intriguing cumin-like spice note to ripe fig and citrusy floral tones, and Old Soul’s Sumatra Gayo “Adsenia” Triple Pick (92) was a particularly lucid wet-hulled coffee without the usual tobacco notes but rich with flowers and chocolate.

Along with the seven wet-hulled Sumatras, we review one fully dried-in-the fruit “natural”-processed sample, the 93-rated Crescendo Wahana Estate, an impressive example of the natural style with its lush sweetness, chocolaty fruit and understated hint of brandyish ferment. One conventionally wet-processed or “washed” sample, the Café Backstage Sumatra King Batak, made the cut at 92. It appeared to reflect in its crisp delicacy and gentle tartness the greater clarity we expect from conventionally wet-processed coffees.

Finally, we review two honey-processed coffees, both complex, interesting, but difficult to decisively generalize on by processing method alone. The 93-rated Taiwan-roasted Once N Café Etude Meriah Aceh King Batak could well read as a wet-hulled Sumatra, though more delicate perhaps in its sweet molasses-inflected tobacco and fragrant magnolia-like flowers. The King Batak Honey (92) from Studio Confluence (another Taiwan roaster) more clearly fits our processing method expectations: It is definitely crisper and zestier than the typical fine wet-hulled Sumatra, with nothing earthy or tobacco-like about it.

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About the Author:

Kim Westerman is a licensed Q-grader, a longtime food, wine and travel writer and a certified sommelier. Her work has been published in the New York Times, Forbes, the San Francisco Chronicle, Bay Area Bites, and many other publications. She happily brings her sensory training in wine to the evaluation of coffee in Coffee Review’s Berkeley lab. She also handles communication with roasters and review logistics.

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