Sour

Acidity in Coffee

In specialty coffee, acidity is not a negative word. It refers to the pleasant brightness and liveliness of the cup. Good acidity, like the freshness of white wine or ripe fruit, gives flavor dimension; coffee without it is often called flat or lifeless.

Acidity vs. Sourness

The two are often confused, but in coffee tasting they mean different things:

• Good acidity: bright, clean and accompanied by sweetness — like citrus, apple or berries
• Unpleasant sourness: sharp, harsh and thin, usually from under-extraction, under-developed roasting or fermentation defects

Many people who "don't like acidic coffee" have actually tasted under-extracted or low-quality coffee rather than genuine good acidity.

Common Types of Acidity

• Citric acid: bright, direct citrus; one of coffee's main organic acids
• Malic acid: crisp and bright like green apple, common in Kenya and Colombia
• Phosphoric acid: often used to describe the sparkling, refreshing acidity of Kenyan coffee
• Lactic acid: round and soft like yogurt, common in anaerobic fermentation
• Tartaric acid: a round, grape-like acidity
• Acetic acid: adds fermented fruit in small amounts, unpleasant in excess
• Chlorogenic acids: the most abundant acids in green coffee; they break down heavily during roasting and affect bitterness and astringency

What Influences Acidity?

• Altitude: higher altitude and larger day-night swings usually mean more organic acids
• Processing: washed coffees usually have the brightest acidity
• Roast: light roasts preserve the most acidity; dark roasts greatly reduce it
• Variety: SL28 and Geisha have naturally excellent acidity
• Extraction: acids extract first, so under-extracted coffee tastes sour

Making Acidity More Enjoyable

• Grind a little finer, use hotter water or brew longer so sweetness catches up with acidity
• Let the coffee cool slightly — acidity becomes rounder
• If it still feels too sharp, choose a medium roast or a natural or honey-processed coffee