Why Your Meter Says 150 ppm But Your Coffee Still Tastes Flat
You've done your research. You know the Specialty Coffee Association (SCA) suggests a TDS (Total Dissolved Solids) reading of around $150$ ppm (parts per million) for the best flavor. So you bought a TDS meter, tested your tap water, and got a respectable $180$ ppm. Great, right? Then you brew a high-end specialty coffee, and it tastes... flat, dull, or aggressively bitter . This is the TDS Trap : relying solely on the final number without understanding what minerals actually make up that total. Your meter is telling you how much stuff is in your water, but it's lying about the quality of that stuff. Not All Solids Are Created Equal: Temporary vs. Permanent Your water's overall TDS reading is composed of two fundamentally different groups of minerals that have opposite effects on your coffee and your machine. A. The Flavor Killers & Scale Builders (Temporary Hardness) This group is primarily made up of Calcium and Magnesium Carbonates and Bicarbonates (Alkali...