underextracted

Underextracted is a term used in the context of coffee brewing to describe a cup in which insufficient soluble compounds have been dissolved from the ground coffee during the brew. Such coffee often tastes sour or grassy, with a thin body and little sweetness, and may lack aroma and overall balance.

Causes include grind size too coarse, too short a brew time, water temperature too low, inadequate agitation or poor flow through the bed, and sometimes an insufficient coffee dose relative to the water. The result is incomplete extraction of sugars, acids, and aromatics, leaving primary, sharp flavors unbalanced.

Indicators are primarily sensory: pronounced sourness or acidity, weak body, flat sweetness, and muted aroma. The cup can also feel underdeveloped or insipid compared with a properly extracted brew. In professional practice, extraction yield (EY) can be estimated but is most often measured with a refractometer; a typical target EY for brewed coffee is about 18-22%. Underextraction is indicated when EY is below this range.

Prevention and correction focus on enabling more complete extraction: grind finer; adjust dose and dose distribution; extend contact time, particularly for immersion methods; ensure water temperature is within an optimal range (roughly 90-96°C for most methods); improve agitation and agitation patterns to promote uniform extraction; allow for a proper bloom in pour-over and ensure adequate flow in espresso or drip methods. By comparing method, grind, and timing, baristas can bring the cup toward a balanced profile.