Drop Water Temperature to 80°C - 85°C (176°F - 185°F)
Never pour boiling 100°C water onto dark supermarket beans. Boil your kettle, take the lid off, and let it cool for 3 to 4 minutes (or add 10% room-temperature water) to reach 82°C-85°C before brewing.
Dark roasting fractures bean cell walls and breaks down chlorogenic acids into harsh bitter lactones and phenylindanes. Lower water temperature drastically reduces the solubility of these bitter compounds while preserving pleasant caramel and chocolate oils.

