- Also called: TDS
- Availability: Specialty
TDS is the percentage by mass of dissolved coffee compounds in the finished beverage, measured with a handheld refractometer. For drip and pour-over, the SCA "ideal" range is roughly 1.15%–1.45% TDS at an 18–22% extraction yield. For espresso, TDS is much higher, typically 8%–12%. The measurement turns subjective brew tweaks into data — useful for dialling in batch brew, less commonly used at home.