What is the difference between sour and acidic?
Acidic describes a good coffee's bright, juicy flavor, balanced by sweetness and body. Sour describes a brewing fault: a sharp, vinegary, unripe taste from under-extraction. Think green apple (acidic, pleasant) versus vinegar (sour, harsh).
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On a cupping table, acidity is a scored attribute: cuppers reward intensity balanced by sweetness, and penalize sharpness with no support. That distinction is the whole game. An acidic cup invites another sip; a sour cup makes you wince.
The two share a chemistry family — both are organic acids — but the balance determines which word you reach for. The same coffee can taste acidic at a correct extraction and flat-out sour if it is ground too coarse or brewed too cool, because under-extraction serves the sharp acids without the sweetness to hold them up.
When you read a tasting note that says 'bright acidity', read it as praise. When your own brew tastes sour, treat it as a brewing signal, not a character flaw of the bean.
- · Specialty Coffee Association — Coffee Standards: https://sca.coffee/research/coffee-standards