What's the Ideal TDS for Coffee Brewing?
TDS (Total Dissolved Solids) measures the mineral content of your water. Both too high and too low TDS negatively affect extraction — but in different ways.
⚡ Quick Answer
The SCA (Specialty Coffee Association) recommends 75–250 ppm TDS for brewing water, with 150 ppm as the target. Water below 50 ppm extracts poorly (flat, lifeless taste). Water above 300 ppm tastes minerally, can impede extraction, and builds scale rapidly in machines. For espresso specifically, 75–150 ppm is the sweet spot.
🎯 Target Range: 75–150 ppm for espresso. 75–250 ppm for filter coffee. Below 50 ppm = add minerals. Above 300 ppm = filter or blend with softer water.
⚙️ TDS Range Effects
| TDS Range | Effect on Coffee | Machine Risk | Action |
|---|---|---|---|
| <50 ppm | Flat, lifeless, under-extraction | May leach metals | Add minerals (TWW or DIY) |
| 75–150 ppm ✓ | Excellent extraction, clean flavor | Low scale risk | Ideal — use as-is |
| 150–250 ppm | Good but slightly minerally | Moderate scale | Acceptable, descale regularly |
| >300 ppm | Minerally taste, impeded extraction | High scale risk | Filter, blend, or use bottled |
✅ How to Measure Your Water's TDS
A TDS meter costs $10–20 on Amazon. Dip it in your cold tap water for a reading in seconds. Note: TDS meters measure conductivity, not specific minerals — but it's a good proxy for water quality for coffee purposes.
- • Fill a clean glass with cold tap water (filtered or unfiltered)
- • Dip the TDS meter and wait for a stable reading
- • If above 300 ppm: filter or blend with lower-TDS water
- • If below 50 ppm: add minerals via Third Wave Water or DIY recipe
- • If 75–250 ppm: you're in good shape, check hardness and chlorine separately