Mastering the Roast of Indonesian Wet-Hulled (Giling Basah) Coffees

 Indonesian coffees—especially those processed using the traditional wet-hulling method (giling basah)—are known for their dense body, earthy depth, syrupy mouthfeel, and unique rustic character. However, these same traits can make them challenging to roast. Wet-hulled beans typically arrive with higher moisture variability, softer structure, and unusual drying curves, which require a thoughtful approach to heat and airflow.

At Scofi, the roasting philosophy focuses on balancing the trademark body of Indonesian coffees with improved clarity, showcasing flavor notes beyond the classic earthy profile. Achieving this balance comes down to one key framework: smart charge temperatures, measured heat application, and deliberate airflow control.

Understanding Wet-Hulled Behavior in the Roaster

Wet-hulled coffees behave differently from washed or natural lots because of their partially dried parchment removal process. They usually retain:

• Higher internal moisture

• Fragile bean structure

• Irregular surface texture

• Quicker heat absorption
  
  

As a result, they can rush through drying, stall unexpectedly in Maillard, or develop harsh, smoky tones if heat is mismanaged. The goal is to guide them gently but steadily.

Smart Charge Temperatures: Setting the Tone Early

Scofi recommends tailoring the charge temperature to the density and moisture of the lot:

1. Moderate to High Charge (195–210°C Drum Temperature)

Wet-hulled coffees benefit from a confident charge, but not an overly aggressive one. A high enough starting point helps:

• Move moisture out efficiently

• Prevent a slow, muddy start to the roast

• Maintain momentum into Maillard
  
  

However, too much initial heat can scorch the softer beans or push them through early phases too quickly.

2. Avoid Overloading the Roaster

Because wet-hulled beans tend to heat rapidly and release moisture unevenly, overcharging the drum can create:

• Excess steam

• Uneven yellowing

• Smoky contamination
  
  

Scofi prefers slightly smaller batch sizes for maximum control.

Airflow Strategy: The Key to Clarity

Body is already a natural strength of Indonesian coffees. What they need is clarity, and airflow is the most effective tool for this.

Early Stage: Moderate Airflow

At the start, too much airflow can strip heat energy from the drum. Moderate airflow helps:

• Carry moisture out steadily

• Prevent rapid temperature fluctuations
  
  

Mid-Roast: Increase Airflow for Clean Maillard

As browning begins, ramping up airflow helps:

• Reduce humidity in the drum

• Prevent smoky or vegetal notes

• Encourage clean caramelization
  
  

Final Stage: High Airflow to Avoid Smoke Taint

Wet-hulled coffees can release oils and cellulose fragments that scorch easily. Strong airflow near first crack prevents:

• Bitter woodiness

• Heavy smoke buildup

• Murky or “dirty” cup profiles
  
  

Scofi’s approach ensures the coffee retains its thick body but gains definition.

Heat Application: Guided Acceleration for Balanced Cups

The hallmark of a good Indonesian roast is a smooth rate of rise curve—strong early momentum that slows gracefully into first crack.

1. Keep Drying Active but Controlled

Rushing through drying leads to musty or underdeveloped aromatics. Aim for 4–5 minutes with a smooth temperature climb.

2. Lengthen Maillard for Flavor Depth

Because wet-hulled coffees can taste muddy when underdeveloped, a generous Maillard phase (3–4 minutes) enhances:

• Caramel sweetness

• Herbal and cocoa notes

• Overall structure
  
  

3. Avoid Rolling First Crack

First crack in Indonesian beans can be soft. A controlled approach prevents overshooting into smoky, heavy body with no nuance.

Cup Results: Big Body With Improved Clarity

When roasted with Scofi’s balanced method, Indonesian wet-hulled coffees transform. Instead of only the traditional profiles—earthy, herbal, smoky—the cup opens to:

• Dark chocolate

• Sweet spice

• Cedar and tobacco nuance

• Clean herbal tones

• Subtle fruit acidity
  
  

The body remains syrupy and bold, but the finish becomes cleaner, smoother, and more refined.

Final Thoughts

Indonesian wet-hulled coffees are some of the most distinctive in the world, but they demand skillful roastery decisions. Using smart charge temperatures, progressive airflow, and controlled heat application, Scofi’s roasting approach brings out the best in these complex beans—delivering cups that are rich, full-bodied, and surprisingly clear wet hulled coffee process.