DIAGNOSIS Inadequate water temperature is the most likely cause of uniformly weak coffee. Mineral scale buildup on the heating element reduces thermal transfer efficiency, preventing water from reaching the optimal 195-205°F brew temperature.
FIX Descale the machine immediately. Use a commercial descaling solution formulated for coffee makers or a citric acid solution. Fill the reservoir with the descaling solution. Run a full carafe brew cycle without coffee. Discard the water. Refill the reservoir with fresh water and run two additional full carafe cycles to flush all descaler residue.
IF THAT DIDN'T WORK If coffee remains weak after descaling, the thermostat regulating the boiler temperature may be failing. This is a less common but possible failure. To test, brew a cycle into a mug and immediately check water temperature with a kitchen thermometer. It should read between 195°F and 205°F. A reading below 185°F confirms a heating system fault.
HEADS UP Regular descaling is mandatory for performance, not optional. Hard water requires descaling every 1-2 months. Neglect leads to permanent scaling that can clog lines and eventually cause the heating element to overheat and fail.