Why does pour-over taste bitter?

Bitterness in coffee is a sign that the extraction process has gone too far. While some bitterness is a natural part of coffee's flavor profile, it should be balanced by sweetness and acidity. When a pour-over tastes unpleasantly bitter, it means the water has spent too much time in contact with the grounds or has been too efficient at pulling out the harsh, dry-tasting compounds found in the coffee bean structure.

The most common culprit is grind size. If your grind is too fine, the water encounters more surface area and flows through the bed of coffee more slowly, leading to over-extraction. If you find your brew is taking significantly longer than expected, your grind is likely the issue. Try adjusting your grinder to a slightly coarser setting to speed up the flow rate and reduce the contact time.

Water temperature also plays a role. If your water is at a rolling boil, it may be extracting those bitter compounds too quickly. While 200°F is a standard target, if you are consistently getting bitter results, try dropping your water temperature by a few degrees. Additionally, ensure your pouring technique is consistent; pouring too aggressively or unevenly can cause 'channeling,' where water finds a path of least resistance through the coffee bed, leading to uneven extraction and bitter spots.

In practice, change only one variable at a time. Start by coarsening your grind size by a few clicks. If the coffee still tastes bitter, try lowering your water temperature. By isolating these variables, you can identify exactly what is causing the bitterness and dial in your recipe for a cleaner, sweeter cup. Remember that 'bitter' is different from 'burnt'—if the coffee tastes like ash, it may be the roast itself, but if it tastes dry and astringent, it is almost certainly an extraction issue.