TDS
Total Dissolved Solids — the percentage of your brewed coffee that is dissolved solids vs. water. Measured by a refractometer. The most direct way to quantify a coffee's strength.
TDS (Total Dissolved Solids) is the percentage of brewed coffee, by mass, that consists of dissolved coffee compounds rather than water. A 1.30% TDS pour over contains 1.30 grams of dissolved coffee per 100 grams of beverage.
How TDS is measured
TDS is measured with a coffee refractometer — a small instrument that reads the refractive index of a coffee sample and converts it to a percentage. Common consumer refractometers are the Atago PAL-COFFEE, VST LAB III, and DiFluid R2.
To take a reading: cool a small sample of the brewed coffee to room temperature, filter or skim off oils (especially for espresso), drop 2–3 drops onto the prism, close the lid, and read the displayed percentage. Most users take three readings and average them.
Typical TDS ranges
| Brew method | Typical TDS |
|---|---|
| Espresso (traditional) | 8–12% |
| Pour over (V60, Origami, Kalita) | 1.20–1.45% |
| AeroPress | 1.30–1.60% |
| Batch brew / drip | 1.15–1.35% |
| French press | 1.20–1.40% |
| Cold brew (concentrate) | 1.50–2.50% |
TDS vs. extraction yield — what's the difference?
TDS measures strength (how concentrated the beverage is). Extraction yield measures efficiency (what percentage of the dry coffee dissolved into the cup). They are different numbers, both derived from a TDS reading.
Extraction Yield % = (TDS × Beverage Mass) ÷ Dose
Example: 18 g espresso dose, 36 g shot, TDS reads 9.5%. Extraction yield = (9.5 × 36) ÷ 18 = 19.0%. The shot is 9.5% strong and 19% efficient. Use the extraction calculator →
Why TDS matters
Strength and taste track together up to a point. A 0.80% TDS pour over tastes watery; a 1.60% TDS pour over tastes overwhelming. The 1.20–1.45% range is where most coffees taste their best — sweet, balanced, with discernible flavour notes. Outside that window, even good extraction can taste off.
TDS is also the bridge to extraction yield. Without a TDS measurement, you can't compute extraction; without extraction, you can't tell whether a cup that tastes bitter is actually over-extracted or just too strong.
Related terms
- Extraction Yield — the percentage of dry coffee that dissolved into the cup.
- Brew Ratio — the dose-to-beverage ratio that sets the TDS range.
- Dial-In — the workflow that uses TDS as one of several feedback signals.
Read more
Full guide: TDS and extraction yield →
Track TDS automatically with every brew.
Log dose, yield, and TDS — extraction yield calculated, zone visualised, history saved.
