Water Quality for Matcha Preparation
Soft water with 50–100 ppm total dissolved solids (TDS) extracts matcha's umami compounds most effectively. Calcium and magnesium ions above 150 ppm competitively bind L-theanine and suppress the smooth mouthfeel characteristic of high-grade ceremonial matcha.
| Measure | Value | Unit | Notes |
|---|---|---|---|
| Optimal water hardness (TDS) | 50–100 | ppm | Soft water; produces clearest umami expression and smoothest texture |
| Acceptable water hardness (TDS) | 100–150 | ppm | Slightly harder water is acceptable; minor flavor suppression |
| Not recommended hardness (TDS) | >200 | ppm | Hard water significantly reduces perceived umami and amplifies bitterness through mineral-catechin interactions |
| Chlorine effect | Negative | Chlorine and chloramine in municipal tap water create off-flavors; use filtered water or let tap water rest uncovered 30 minutes | |
| Optimal brewing temperature | 70–80 | °C | Never boiling water (100°C) — degrades amino acids and creates harsh bitterness; 70°C for premium ceremonial, 75–80°C for culinary |
| pH preference | 6.5–7.5 | Neutral to slightly acidic water; highly alkaline water (pH > 8) accelerates chlorophyll degradation and color shift |
Water quality is the most overlooked variable in matcha preparation. The mineral content, chlorine levels, and pH of water all affect the flavor profile of the final cup.
Hardness and TDS
Total dissolved solids (TDS) measure all minerals, salts, and metals dissolved in water. For matcha, calcium and magnesium ions are the primary concern.
Soft water (50–100 ppm TDS):
- Minimal ion competition with amino acids
- Full L-theanine sweetness expressed
- Smooth, clean mouthfeel
- Vivid green color retained
Medium water (100–150 ppm TDS):
- Acceptable results
- Slight attenuation of umami sweetness
- Most commercially bottled spring waters fall in this range
Hard water (>200 ppm TDS):
- Calcium/magnesium ions bind to tannins and catechins, increasing perceived bitterness
- Suppresses amino acid-derived sweetness and umami
- May cause greenish-gray cloudiness rather than clean suspension
Chlorine and Disinfectants
Municipal tap water in many regions contains chlorine or chloramines. These compounds:
- React with amino acids, creating off-flavors (medicinal, chemical notes)
- Can alter catechin structure at high concentrations
- Are largely volatile — simply resting water in an open container for 30 minutes removes most chlorine (chloramines require filtering)
Best practice: Use filtered water (activated carbon filter removes chlorine and most chloramines) or bottled spring water with TDS 50–100 ppm.
Temperature Interaction
Water hardness interacts with temperature. At higher temperatures, minerals become more reactive. Hard water brewed at 85–90°C will extract more bitterness from matcha than the same water at 70°C. This is another reason to keep brewing temperatures moderate.
Recommended Water Sources
| Source | TDS (approx.) | Suitability |
|---|---|---|
| Filtered tap (carbon) | 30–80 ppm | Excellent |
| Soft spring water (e.g., Volvic) | 50–70 ppm | Excellent |
| Standard mineral water | 150–300 ppm | Acceptable |
| Hard tap water | 200–500 ppm | Poor |
| Distilled water | <5 ppm | Not recommended — flat flavor |
Distilled water (too soft) produces flat, lifeless matcha — some mineral content is needed for the full flavor matrix. The 50–100 ppm range is the sweet spot.
Practical Tip
If only hard tap water is available, compensate by:
- Using a higher-quality matcha grade
- Reducing brewing temperature to 68–70°C
- Using less powder (1.5g instead of 2g) to reduce bitterness
- Filtering with a pitcher-style carbon filter
Related Pages
Sources
- Engelhardt UH (2013) — Chemistry of tea. Reference Module in Chemistry. Elsevier
- Scharbert S & Hofmann T (2005) — Molecular definition of black tea taste by means of quantitative studies, taste reconstitution, and omission experiments. J Agric Food Chem
- Japan Tea Exporters' Association — Water Recommendations for Green Tea