Over Extracted. The term is used in the brewing process (mainly Espresso) when the ground coffee is exposed to hot water and dissolves more than needed, resulting in a bitter and dry taste that overwhelms the senses. Other flavors – also see Extraction fundamentals.
When ground coffee is exposed to hot water and dissolves more than it needs to, the result can be bitter and dry, overwhelming the senses. Other tastes – also see Extraction fundamentals.
To further explain, each roasted coffee bean is approximately 28% soluble in water (by weight). In other words, coffee beans can be extracted in water at a rate of 28 percent by weight. The rest is cellulose, which aids in the shaping of the bean’s vegetative structure; we can split the extraction ratios to assess the quality of a cup of coffee using this information:
If less than 18% of the available solubles in the coffee are removed during the brewing process, it is termed a failure.