What can cause coffee to be overly bitter during brewing?

High brewing temperatures can lead to coffee being overly bitter during the brewing process. When water temperature exceeds the optimal range, typically between 195°F and 205°F (90°C to 96°C), it can cause the extraction of undesirable compounds from the coffee grounds. These compounds are often acidic and bitter, resulting in an unpleasant taste.

In contrast, using high-quality coffee beans generally contributes to a better flavor profile, as they are more likely to be sourced from premium varieties and processed properly. A long brew time with cold water is less effective in extracting flavors and wouldn’t typically result in bitter coffee; instead, it could lead to under-extraction, where the coffee tastes weak or sour. Utilizing a drip coffee maker doesn't inherently cause bitterness, as the machine can brew coffee at the appropriate temperature and time when used correctly.