Brewing Basics
TDS
Total Dissolved Solids, a measurement of the concentration of dissolved coffee compounds in the brewed liquid, expressed as a percentage. The SCA recommends a TDS between 1.15% and 1.35% for filter coffee.
En Profundidad
TDS is measured with a digital refractometer by placing a small sample of brewed coffee on the lens. Combined with the brew ratio, TDS allows calculation of extraction yield, giving baristas an objective framework to evaluate and communicate recipes. A cup at 1.15% TDS tastes lighter and more transparent, while 1.45% or above may taste heavy or muddy to many palates.