Why does my coffee taste different from café to café?
A café cup is the outcome of multiple measurable variables. Two shops can use the same origin and still produce different sensory results because brew strength (TDS) and extraction yield shift the balance of acids, sugars, and bitter compounds.
The Brewing Control Chart framework exists precisely to map how strength and extraction influence perceived balance. Water chemistry is another major lever; hardness and alkalinity influence extraction and perceived acidity, and official water guidance emphasizes measuring and targeting those values.