The world’s most consumed beverage, water comes before tea, which is itself 99% water. Yet this chemical solvent is the most decisive and most underestimated factor in tasting. To release the active compounds and nuances of a grand cru without stifling its terroir, brewing water must be strictly still, very low in minerals (dry residue at 180 °C strictly below 50 mg/L), with a neutral to slightly acidic pH, between 6.0 and 7.0.
Technical note on carbonation: sparkling waters are entirely excluded from this reference guide. Dissolved carbon dioxide forms carbonic acid, which causes the pH to collapse, destroys the molecular balance, alters umami and prematurely oxidises plant catechins.
The still water reference guide: more than 100 entries
| Category and mineral content | Brands listed | Dry residue | Average pH | Chemical behaviour and verdict |
|---|---|---|---|---|
| THE GRANDS CRUSThe pure solventLess than 50 mg/L | France : Mont Roucous (22 mg/L), Montcalm (32 mg/L), Rosée de la Reine (27 mg/L), Source des Pins (45 mg/L), Celtic still (48 mg/L), Volcania (35 mg/L). Italy : Lauretana (14 mg/L), Sant'Anna Rebruant spring (22 mg/L). Iberian Peninsula : Bezoya (28 mg/L), Agua de Luso (45 mg/L). Scandinavia and Northern Europe : Voss still (44 mg/L), Isbre (10 mg/L), Svalbarði (15 mg/L), Gorski Kotar (Croatia). North America : Iceberg Water (9 mg/L), Berg (10 mg/L), Amaro, Labrador, Aquafina (reverse osmosis, less than 10 mg/L), Dasani (less than 30 mg/L), Smartwater (rebalanced distilled vapour). Asia and the Pacific : I LOHAS (Japan, 25 mg/L), Suntory Tennensui (Japan, 30 mg/L), Wahaha purified (less than 20 mg/L), Cestbon (China, less than 15 mg/L). Exceptional waters : Bling H2O, Acqua di Cristallo, Fillico Jewellery Water. | less than 50 mg/L | 5.8 to 6.8 | Optimal extraction without interference. The absence of dissolved limescale allows the solvent complete permeability and fully preserves L-theanine and natural sweetness. Essential for green teas first flushes, the emulsification of Matcha and the purity of white teas. |
| THE ACCEPTABLESThe structuring compromise50 to 150 mg/L | France : Volvic (130 mg/L), Abatilles still (120 mg/L), Ogeu still (140 mg/L), Wattwiller still (150 mg/L), Saint-Benoît (125 mg/L), Mont Blanc (110 mg/L), Carola still, Aix-les-Bains (130 mg/L), Luchon still. Italy : Acqua Panna (140 mg/L), Levissima (80 mg/L), Rocchetta (135 mg/L), Sorgesana (120 mg/L). Central Europe and the United Kingdom : Highland Spring still (170 mg/L), Lanjarón (120 mg/L), Valvert (150 mg/L), Vilsa still, Bad Meinberger, Franken Brunnen, Żywiec Zdrój (Poland), Radenska Naturelle still, Iskilde (Denmark), Tau (United Kingdom). The Americas : Poland Spring, Deer Park, Ozarka, Ice Mountain, Proud Source, Liquid Death Mountain Water still, Boxed Water Is Better, Just Water, Eska (85 mg/L), Naya, Bonafont (Mexico). Asia and the Pacific : Nongfu Spring (70 mg/L), Aqua (Indonesia), Himalayan (Tata), Kinley (India), Mount Franklin, Pump, Antipodes still (130 mg/L), Waiwera still. Middle East and Africa : Masafi (130 mg/L), Mai Dubai still, Al Ain still, Arwa, Sidi Ali (140 mg/L), Ain Soltane, Oulmès still, Ifri still, Saïda, Safia, Sabrine, Valpré. | 50 to 150 mg/L | 6,8 to 7,6 | Roundness and structure. The moderate presence of silica and bicarbonates provides substance without clouding the liquor. These waters support the intensity of black teas oxidized teas, particularly those from the Hunan terroirs, and the pyrogenic profile of oolongs roasted. |
| THE LOTTERYMultiple regional sourcesDepending on the borehole | France : Cristaline (Elena, Aurèle, Roxane, Sainte-Cécile sources, etc.), Nestlé Aquarel, Sources de la Montagne, Roche des Écrins. International : Ciel (Latin America), Bisleri (India, variations depending on regional plants). | 80 to more than 500 mg/L depending on plant | variable (6,5 to 8,0) | Label verification required. A single brand encompasses dozens of different boreholes. Only sources indicating a dry residue below 100 mg/L, such as Cristaline Elena source, are suitable for infusing pure tea. |
| THE DESTRUCTIVE ONESStrictly to be avoidedMore than 180 mg/L | France : Evian (309 mg/L), Vittel (1084 mg/L), Contrex (2078 mg/L), Hépar (2513 mg/L), Courmayeur (2146 mg/L), Thonon (340 mg/L), Plancoët still (250 mg/L), Velleminfroy (2010 mg/L), Saint-Georges. Italy : San Benedetto still, Lete still, Fiuggi, Uliveto. Spain : Solán de Cabras (260 mg/L), Font Vella (300 mg/L), Cabreiroá still. Germany and Central Europe : Gerolsteiner Naturell still, Adelholzener, Jana (Croatia), Roi still. United States and the world : Fiji Water (222 mg/L), Arrowhead, Zephyrhills, Mountain Valley Spring, Core Hydration. Asia : Ganten (230 mg/L), Kunlun Mountains. Africa : Lalla Khedidja (Algeria), Aquafina Africa (mineralized facilities). | more than 180 to 2500 mg/L | often above 7,4 (alkaline) | Saturation and molecular precipitation. Calcium and magnesium ions chemically bind to tannins and polyphenols. The liquor becomes cloudy, develops an iridescent film on the surface and produces a chalky bitterness that masks the vegetal expression of a pure leaf. |
Scientific frequently asked questions
Why does limescale destroy the aromas of specialty tea?
Limescale is composed of calcium and magnesium carbonate. When heated, these minerals saturate the water’s solvent capacity and precipitate the leaf’s polyphenols and theaflavins. This phenomenon blocks the extraction of subtle aromatic molecules, creates a dull film on the surface of the cup and imparts an artificial, harsh bitterness. To understand the complete biochemistry, read our detailed article on water chemistry.
What is the difference in extraction between Mont Roucous and Volvic?
Mont Roucous, with a dry residue of 22 mg/L, is a completely neutral water: it acts as a perfect mirror of the leaf, ideal for revealing the marine notes and umami of green teas or the sweetness of a white tea. Volvic, with 130 mg/L, adds a touch of volcanic minerality that gives greater body on the palate, making it particularly well suited to the tannic structure of black teas and oolongs woody teas.
Can a reverse osmosis system or filter jug be used?
Yes. A filter jug removes chlorine and reduces limescale, which is a notable improvement over untreated tap water. Reverse osmosis is even more effective, provided a minimal residual mineralisation of around 20 to 30 mg/L is retained. Distilled water at 0 mg/L is not recommended: completely devoid of ions, it makes the infusion bland and flat.
Does pure water interact with the teapot’s ceramic?
Absolutely. When very soft water is used, it allows an unglazed porous ceramic , such as Yixing clay or an artisanal kyusu, to reveal its full potential. The clay breathes with the liquor, absorbs excess tannins over successive infusions and polishes the texture on the palate, bringing a unique roundness that stainless steel would neutralise. Our tasting objects are selected with this in mind.
Our sommeliers also welcome you at the counter HOLLIN of Taste in Sartrouville, 22 avenue de la République, for comparative tastings of waters and single-origin teas.