One of the things that surprised me when I started paying attention was how much processing method changes everything about a roast. Same origin, same farm, washed vs. natural — completely different coffee in the cup, and completely different behavior in the roaster.
Here's what I've learned about adjusting your approach based on processing.
Washed (Wet Process)
The clean baseline. Fruit is removed before drying, so you're tasting the bean itself — origin character, terroir, clean acidity.
Roasting notes:
- Most forgiving to roast. Consistent moisture content, predictable crack timing.
- Takes well to light and medium roasts where acidity and clarity shine.
- DTR of 15–20% is a safe starting range.
- Weight loss tends to run slightly higher than naturals at the same visual roast level.
Natural (Dry Process)
The bean dries inside the cherry. More fruit sugars, more body, more wild unpredictability.
Roasting notes:
- Higher sugar content means earlier browning and faster Maillard progression. Watch your color — naturals look darker than they taste.
- More prone to scorching because of the sugar. Consider a gentler charge temp.
- Shines at light-medium to medium. Going too dark burns off the fruit character that makes naturals interesting.
- Weight loss is typically 1–2% lower than washed at the same development level.
- More batch-to-batch variability is normal. Don't expect the same consistency as washed.
Honey / Pulped Natural
Somewhere in between. Some fruit mucilage stays on during drying. Yellow honey (less mucilage) is closer to washed; black honey (more mucilage) is closer to natural.
Roasting notes:
- Roasts similarly to washed but with more sweetness and body.
- Good candidate for medium roasts where you get both origin clarity and caramelized sweetness.
- Black honey can behave more like a natural — watch for early browning.
Anaerobic / Experimental Fermentation
Controlled fermentation in sealed tanks (no oxygen). Produces intense, sometimes polarizing flavors — boozy, tropical, fermented fruit.
Roasting notes:
- Tread carefully. The intense flavors are already there from processing — over-roasting doesn't add complexity, it just adds char to an already complex profile.
- Light to light-medium generally works best. Let the processing speak.
- These are expensive beans. Roast a small test batch first.
Wet-Hulled (Giling Basah)
Almost exclusively Indonesian (Sumatra, Sulawesi, Java). The parchment is removed while the bean is still wet, creating a distinctive earthy, herbal, full-bodied cup.
Roasting notes:
- These beans are built for medium-dark and dark roasts. The earthy, herbal character holds up well at darker levels where washed and natural beans lose their identity.
- Lower density and higher moisture mean longer drying phase. Be patient — rushing the drying leads to grassy, vegetal flavors.
- Irregular bean shape is normal. Some uneven roasting is expected.
- Classic Sumatra Mandheling is a forgiving, reliable bean for learning darker roasts.
How RoastSource Handles This
When you add a coffee to inventory with its processing method, the app factors that into the generated roast profile — charge temp, expected crack timing, DTR targets, and predicted flavor profile all adjust. The quality scoring also uses processing-aware weight loss bands, so a natural that loses 12% isn't graded against the same standard as a washed that loses 15%.
What's your experience been? Do you roast differently based on processing, or do you have a universal approach? Any processing methods I should add more detail on?