Roasting notes for Washed (Wet) process
(from gemini 2.5)
Wet-processed (or washed) coffees are known for their clean, bright, and consistent flavor profiles, often with pronounced acidity and floral or fruit notes. This is because the cherry pulp is removed before drying, which prevents the flavors of the fruit from being imparted to the bean during the drying process.
Here are the key principles and considerations for a roasting and RoR profile for wet-processed green coffee:
1. Key Roasting Characteristics
- Consistency: Wet-processed beans are generally very consistent in size and density, which leads to a more even roast. This allows for larger batch sizes and more predictable results.
- Density: They are typically denser than naturally processed beans. This means they require more energy to roast. You may need to use a higher charge temperature or a more aggressive initial heat application to get the roast started.
- Moisture Content: The moisture content is typically lower and more uniform compared to naturally processed beans. This can shorten the drying phase of the roast.
2. Roasting Profile Strategy
The goal when roasting wet-processed coffee is to preserve and highlight its inherent cleanliness, acidity, and floral notes.
- Drying Phase (Endothermic): This phase is where the green beans absorb heat and moisture begins to evaporate.
- Goal: Dry the beans efficiently without scorching them. A shorter drying phase can help preserve volatile compounds.
- RoR: Keep the RoR high in the initial phase to efficiently drive out moisture.
- Maillard Phase (Endothermic): The beans turn from green to yellow and then brown.
- Goal: Develop sweetness and complexity. The Maillard reaction is a browning process that creates new flavor compounds.
- RoR: Gradually decline the RoR to ensure a good development of flavors without “baking” the coffee. A slow and steady decline is often recommended.
- First Crack and Development Phase (Exothermic): This is the stage where the bean “cracks” and releases internal pressure, along with heat.
- Goal: Control the development of the roast, preserving acidity while adding body and sweetness.
- RoR: You will see a sharp spike in the RoR just before or at the beginning of the first crack. This is the “crash” in the RoR. You’ll need to apply a heat reduction to manage this and maintain a gentle decline. The goal is to avoid a “flick,” where the RoR suddenly rises again after the crash.
- Development Time Ratio (DTR): This is the time from the beginning of first crack until the end of the roast. For a light to medium roast, a DTR of 15-25% of the total roast time is a good starting point. This helps ensure proper flavor development without a “baked” taste.
3. Rate of Rise (RoR) Profile
A typical RoR profile for a washed coffee roast would be a smooth, declining curve.
- Initial RoR: A high RoR at the start (e.g., 20-30°F/min or more, depending on your roaster).
- Middle RoR: A steady decline throughout the drying and Maillard phases.
- End RoR: The RoR should be at its lowest point as you approach the end of the roast, usually around 5-10°F/min (or even lower) during the development phase.
The “ideal” roasting and RoR profile is not a single, fixed graph but rather a set of principles that you must adjust based on the specific coffee, your roaster, and the flavor you want to achieve. Experimentation is key to finding the perfect profile for a particular wet-processed coffee.