Indonesian Fundamentals: Approaches to Roasting Indonesian Coffees and a Look at Rustic Sweetness

By Christopher Schooley 12/11/13

I’ve been thinking about roasting. I’ve been thinking about coffees that take a little more work in the roaster – coffees that many of the coffee folk these days who are more interested in brighter and more acidic coffees frequently dismiss. The clearest examples of this are coffees from Sumatra. They’re long considered the gateway coffees for consumers who are more used to strong, darker roasted coffees. These are not pristine floral and citrusy coffees. They are earthy, heavy, dry, woodsy, herbaceous, and their acidity is not sparkling. These are coffees that you roast not to push acidity but to push their rustic sweetness and mouthfeel.

How do I best describe rustic sweetness? Generally, it’s a quality in coffee that can be quite polarizing because many of these coffees wouldn’t be considered to have fully clean cups and also have muddled qualities in general. Rustic sweetness can have nutty characteristics to it like almond and walnut, but can also be herbaceous or rooty with a somewhat cola or root beer-like sweetness. There can also be a bit of aromatic woodiness to them, which is one thing specifically that makes them polarizing. Specialty Coffee origins that I most associate with producing rustically sweet profiles are: Brazil, Sumatra, Sulawesi, India, Yemen, and Java. Some dry processed and pulped-natural coffees will fit this bill as well.

What is their value in the spectrum of specialty coffee? For starters, these coffees tend to have exceptionally complex body/mouthfeel. Also, these coffees are very distinctive and have quite the following among coffee drinkers, and when there is great care taken in their production, they result in a fantastic cup. They tend to handle a deeper roast profile, and in many cases are much better taken into the Full City range. The rustic qualities are accentuated by more caramelization, and often pair nicely with just a bit of roasty character.

Getting the best out of these coffees is a lot more than just deeper or darker roasting though. It really is about development at every stage of the roast. Slow and steady throughout. One of the main side effects of stretching out the roast at any point is reducing the acidity and brightness. Because the acidity in these coffees tends to be a little ‘sharp’ adding an edge to the cup, reducing that as much as possible is going to help the sweetness come through and even refine some of the mulch character into more pleasant herb-like notes like basil or thyme.

Roasting Indonesian Coffees

Roasting Sumatra

In looking at how to approach these coffees in the roaster, I did 3 roasts of a Sumatra that we consider to be on the “clean” side of the Sumatra profile spectrum, but one that also maintains a good deal of the rustic attributes we’re talking about. I did a standard sample roast development-wise, taking it to a City+ level, and another roast with the same profile but taken into Full City. Then I did a stretched roast where I added about a minute of time to the drying phase as well as some time post First Crack, dropping the roast finally at a Full City level. The notes are as follows:

1. Sample City – Bright ashy-earthiness dry fragrance, slight honey-sweet behind a bright note on the break. Rough, sharp, lemongrass and woody, and tarter as cools with a lot of grittiness. More citric than green grape tart. harsh cup.

2. Sample Full City – More earthy dry fragrance, darker raw honey, sweet but more earth on the break. Much much sweeter than the City roast, but still some rough material in the middle of the pallet. The syrupy root beer finish is nice. Some of the harshness mellows, but so does the sweetness

3. Stretched Drying and post 1st Crack Full City – The aroma on the beans themselves is all honey on toast, really sweet and enticing. Bready, pumpernickel dry fragrance, sweet molasses break. Deep, sweet, softroundLots of dark malty character and sweetness, very bready. More and more green grape as it cools, sweet honey finish, soft Sumatra character just at the front of the palate.

So you see, adding this development throughout the roast is really important in breaking down these harsher elements. Even though the roast level on the 2nd sample added a good deal of sweetness, the rough characteristics are still present. But you can reduce these, not eliminate them, and break them down so that they’re more complementary with the rustic sweetness.

Roasting Sulawesi

We’ve offered some very unique Sulawesi coffees in the past – ones that are note processed in the traditional wet-hulled method, which is common for the region. With wet-hulling, coffee parchment is removed at the same time as the fruit and mucilage of the coffee, and the exposed coffee seed is allowed to tarp-dry right on the ground. The Giling Basah wet-hulled process leads to a very distinct vegetal, mulchy, earthy flavor, and the point could be made that in tasting these coffees you are tasting the process more than the coffee itself, just like in dry processed coffees.

There have been a few really nice, clean Sulawesi coffees that have appeared in the last couple of years, and they’ve shown the potential that lies underneath the processing flavors were some really sweet and lovely coffees. This coffee from Tana Toraja was processed in an almost pulped-natural/honey style, with the removal of the fruit and most of the mucilage but with some remaining on the parchment, and then dried to a fairly low moisture in the parchment. While this results in a much cleaner, clearer cup, there is still some familiar Sulawesi character, specifically in the weighted mouthfeel, but also with a bit of sweet herbaceous notes in the lightest roasts. Here are the notes on 3 roasts that I did of one of these Sulawesi coffees.

1. Sample City – Pointed at front of the palate with lemony citric acidity. Custard-like body, complimenting the lemon with plenty of vanilla wafer cookie in the finish. Sugary-sweet throughout. Some basil-like herbaceousness in the cup, but only as an accent, though it does come out a bit more as it the coffee cools. This coffee is like a complex dessert built from some really simple and clean elements, more cake and cake frosting in the cool cup, with that lemony thread woven throughout. It should be noted that this coffee performed best a couple of days out of the roaster.

2. Sample Full City – A lot of roast character in the front of the warm cup that was a little rough, but the finish was quite sweet. Much more cocoa and also much more of the herbal notes with a more potent basil accent throughout the cup. This cup was the most like the familiar Sulawesi cup, but the finish did have some really lovely honey and cocoa sweetness.

3. Stretched Drying City+ – Super juicy and creamy, very well-structured. The brightness is more integrated into the whole cup with a more melon-like or green grape soft brightness that even had some Guatemala-like black cherry notes in the cool cup through to the finish. Some accents of clove and cinnamon. A very complete cup of coffee with much more depth in the middle and the spice and melon and black cherry.

I approached this one similar to how I would a wet-hulled version, figuring that a stretched drying time would really push the sweetness as well as take some of the citric edge off of the acidity without moving into any of the more roasty characteristics of the Full City version. The results were spot on. The stretching is really a function of both expressing the sweetness as well as best developing the weighted mouthfeel in this coffee.

Roasting Java

Well prepared Javas vary greatly depending on how they’re handled in the roaster – they can be dense and rustic, juicy and fruited, or even a combination of the two, with notes of apricot, almond liquor, and cocoa in the finish. This particular Java really needs to get into City+ range at the very least for it to open up. In the lightest roasts of this coffee, the starchiness tends to overwhelm the cup and there’s also an aromatic wood element that becomes more spiced cocoa as you take the roast deeper. You’ll notice in my notes though that it’s not just a roast level thing. It’s also understanding how roast development opens up this coffee’s potential and helps you get the most out of it. I did 3 roasts of a Java, a standard sample roast development-wise, taking it to a City+ level, and another roast with the same profile but taken into Full City. Then I did a stretched roast where I added about a minute of time to the drying phase, dropping the roast finally at a Full City level.

1. Sample City+ – Tart brightness detected in dry fragrance, apricot. The body is a little silty and starchy. Tart brightness on the tip of the tongue that carries through the middle of the palate but that isn’t really in the finish. The cup cools nicely, almond liquor throughout the cup, with a big middle. The tartness/brightness is nice, but it finishes with more of the dry walnut/almond acidity.

2. Sample Full City – Cookie-like sweetness in the dry fragrance with walnut notes in the break. There’s a long sweet finish with a little bit of stone fruit or even papaya, a pungent floral fruitiness. Mouthfeel is still a little silty throughout, pulpy as it cools which lends itself to the rich fruited notes. More and more pulpy as it cools, finishes with even more dry walnut than the City +. There’s some sweetness in both this cup and the City+ cup that’s just begging to be opened up.

3. Stretched City+ – The deepest and sweetest dry fragrance and break. Much longer sweeter finish, with tanginess, and a lot more of that papaya-like pungently floral fruitiness. Not as big in the middle as the Full City roast, but the longer and sweeter finish more than makes up for that. There’s apricot, more of the papaya throughout the cup, and even some of that tangy blackberry.

Knowing that this coffee has more potential sweetness and looking to take some of the silty-ness and starchy-ness out of the body, I felt that stretching the drying stage by 30 seconds to a minute, as well as stretching the 1st crack itself for maybe an extra 20 seconds, would help to achieve what I was trying for in the cup. And it worked in a big way. The stretched roast approach definitely gives the cup the best mouthfeel, juicy throughout, and maybe not as much of a peak in the acidity in the middle of the palate but the sweetness in the cup makes up for it. The cold cup is like chocolate syrup, especially when brewed, and laced with blackberry brightness throughout.

Notes on Some of the Components of Rustic Sweetness…

Herbaceousness and Tartaric Acid

Coffees from Sumatra and Sulawesi are frequently tagged with mulch, or jungle floor-like characteristics. But when the coffee is carefully selected and processed, those same qualities come out much more as herbaceous flavor, like sweet basil or nutty/spicy arugula. Full City roast levels bring out overt cola-like sweetness, with even a slight fruited-ness to it. So are these herbaceous qualities the result of tartaric acids? Tartaric acid tends to lend more of a sourness and less of a sweetness to coffee and is common in grapes which often leads to herbaceous flavors in white wines. I certainly see a green grape character in these qualities, although it’s certainly buried under the rest of the flavor profile. At a City roast, the mouthfeel is often a little starchy, but at City+ and Full City it’s like olive oil coating the palate. Stretching the drying stage and/or the post First Crack stage really helps express the mouthfeel of these coffees better, reducing the harshness and starchiness. The herbaceous qualities fold nicely into the cola or even chocolate toffee sweetness (think “Tootsie Roll”) which is the result of caramelization at this level.

Nuttiness in Sweetness, Body, and Acidity
When we use almond as a descriptor we are generally talking about sweetness. There is a bit of fattiness and dryness in the aftertaste, but in tasting the familiar almond flavor it often comes off more as baked goods like cake or brownies. There is a liquor-like quality to the sweetness that isn’t as pronounced in the other 2 nuts here. There’s more flavor throughout the palate as well. Really nice coffees from Java have toasted almond notes at most roast levels from City through Full City.

Peanuts are generally associated with fattiness, creamy mouthfeel and long-lasting aftertastes. There is a sugary sweetness underneath all the fattiness, more sugary than liquor-like. One thing that the fattiness really counters is the dryness. There is a much less bittering dryness in the peanut compared to the other 2 nuts. Coffees from Brazil can frequently have some sweet peanut flavors and attributes.

Walnuts are the driest of these three nuts. The depth of flavor is also the lightest, as well as the sweetness. That dryness really takes on a presence though. There may be little aftertaste, but the dryness lingers for some time. Dryness like this can really help accentuate certain fruited aromatics though. Walnut-like dryness paired with an apricot note can really pronounce that stone fruit sweetness. There is more of a siltiness to the mouthfeel as well, some of the liquor-like qualities found in the almond, but not with the same depth. Coffees from Sumatra, Sulawesi, and Java have a nice walnut type nuttiness, and coffees from Colombia often also show some of that bracing dry walnut-like acidity.

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