Water is 98–99% of your coffee. Yet most home brewers never think about it. Water chemistry is one of the most impactful — and most overlooked — variables in coffee brewing.
Why Water Chemistry Matters
Minerals in water act as a "bridge" that attracts and carries flavor molecules from coffee into your cup. Without the right minerals, flavor can't extract properly. With too many minerals, water becomes too hard and mutes delicate flavors.
Key Parameters
Total Dissolved Solids (TDS): The total concentration of dissolved minerals. SCA (Specialty Coffee Association) recommends 75–250 ppm. Tap water ranges from near 0 (distilled) to 400+ ppm.
Calcium Hardness: Calcium carries bitter compounds. Moderate levels are ideal; high levels emphasize bitterness.
Magnesium: Magnesium carries sweet and bright flavor compounds. A little magnesium dramatically improves flavor brightness.
Alkalinity (Bicarbonate): Acts as a buffer that neutralizes acidity. Too high and it suppresses the bright acidity that makes great coffee great.
pH: Slightly acidic water (6.5–7.5) is ideal.
Practical Solutions
Use filtered water: A simple Brita filter removes chlorine and reduces hardness. Already an improvement.
Use bottled water: Evian, Volvic, and similar mineral waters work well. Check the label for mineral content.
DIY water: Companies like Lotus Coffee Water sell mineral packets. Add to distilled water for complete control.
Third Wave Water: Pre-made mineral packets designed specifically for coffee brewing.
The Worst Waters
For most people, a filtered pitcher with moderate mineral content is the ideal starting point.
