Coffee Extraction

Coffee extraction is the fundamental process of brewing, during which hot water washes out (dissolves) from the ground bean the aromatic oils, acids, sugars, and other flavour compounds. It is precisely on the quality of extraction that the taste of the drink in the cup depends.

Balance here is critically important. Under-extraction (when too few compounds have been washed out) gives a sour, “empty,” and expressionless taste. Over-extraction (when too much has been washed out, including undesirable bitter compounds) makes the coffee bitter, astringent, and “burnt.” An ideal, balanced extraction reveals all the sweetness and fullness of the bean's flavour. Extraction is controlled by four main variables: the degree of grind, the temperature of the water, the time of brewing, and the ratio of coffee to water. Understanding extraction is the foundation of foundations for any barista who aims to make the perfect cup of coffee.