Extraction is everything there is to brewing coffee and describes the process by which water dissolves coffee's soluble compounds.
This guide will explore how to achieve an ideal extraction and how to identify over and underextraction.
Part I will cover the main, manipulable variables involved in the brewing process.
Coffee to water ratio
The right ratio of coffee to water will extract the correct amount of solids while also producing a cup at a palatable strength.
Grinding coffee exposes surface area necessary for water to dissolve solids. A finer grind increases extraction while a coarser grind decreases extraction.
The more or less time water stays in contact with coffee the more or less it will extract.
Temperature affects the rate of extraction; hotter temperatures extract more quickly while cooler ones extract more slowly.
Agitation describes the movement of water through the coffee bed during the brewing process. A more turbulent brew translates to increased extraction.
Part II will cover the flavors associated with under, over, and ideal extraction.