What kind of water should you use for tea and herbal teas?
Sep
Try this experiment sometime—it’s eye-opening: the same tea, the same amount, the same steeping time, in two teapots—one filled with tap water from a hard water region, the other with soft water. They taste like two different products. The first cup is dull, a bit astringent, and sometimes cloudy on the surface; the second is clear, fragrant, and bright. In our guides on brewing techniques, we always mention water briefly. It was time to dedicate the comprehensive feature it deserves—from the most delicate green tea to an evening herbal tea.
1. Limescale: France’s No. 1 enemy
Visit water hardness, which is its content of dissolved calcium and magnesium—in other words, limestone. It is measured by the TH, expressed as °F : One French degree corresponds to 10 mg of calcium carbonate per liter. The thresholds vary slightly from one source to another, but the standard scale is clear: below 15 °f, the water is considered soft; above 25 to 30 °f, it is hard. Much of France (the Paris Basin, the North, the East, and the Mediterranean coast) falls in the upper half of the scale; Brittany, the Massif Central, and the Pyrenees are better off.
Why is this a problem for the infusion? Because excess minerals come between the water and the tea leaves: extraction is less thorough, the volatile aromas are stifled, and the bitterness becomes more pronounced. With black tea, hard water even forms a thin, iridescent film on the surface of the cup—perfectly harmless but unappealing. Not to mention the limescale that builds up in the kettle with every use.
What changes in the cup: Muted aromas, more pronounced bitterness, and a film on the surface of black teas. How can you tell: Water hardness is often listed on your water bill or your water utility’s website, and the test results for each municipality are published by the Ministry of Health. A quick way to tell: check the bottom of your kettle.
2. Chlorine: that swimming pool taste in your cup
Chlorine is added to tap water to ensure its microbiological safety, which is a very good thing. The downside is its taste and odor—which vary greatly depending on the water system—and which can overpower the delicate aromas of green tea or a floral herbal tea. Good news: this is the easiest problem to fix. Chlorine is volatile: a pitcher of water left open for about an hour—or simply filtered through an activated-carbon pitcher—will lose most of it.
What changes in the cup: a chemical note that overpowers the aromas, particularly noticeable in green teas and floral infusions. The remedy: air-drying or activated-carbon filtration.
3. Minerality: How to Read a Bottled Water Label
If you choose bottled water, one number matters more than any other: the dry residue at 180 °C, that is, the amount of minerals remaining after one liter of water has been evaporated. It is listed in the analysis table on every bottle of natural mineral water. And the accompanying statements are not just slogans: they are established by Annex III of the European Directive 2009/54/EC on natural mineral waters.
Very low mineral content
A selection of the most delicate teas (green, white, and floral infusions): nothing stands between the tea leaf and you.
Low in minerals (or oligomineral)
The broad family of everyday waters. When it comes to tea, tea experts agree: the lower the dry residue in this category, the better.
Rich in minerals
Waters with their own—often distinct—flavor. Best saved for the table: in a teapot, they overpower everything.
Two useful points to note. First, spring water and natural mineral water are not synonymous: the latter must have a consistent composition and is required to display its analysis chart, while the former is not. For tea, it’s the dry residue that matters, not the category. At the other extreme, distilled or highly reverse-osmosis-treated water—which is almost devoid of minerals—paradoxically produces a flat, uninteresting cup of tea. Tea needs a little minerality to have body: just enough, not too much. This is exactly what “low-mineral-content water” describes.
4. Tap, carafe, or bottle? The answer in 3 questions
Is your tap water soft and free of any chlorine taste? If so, stop right there: you already have the best water possible—free and plastic-free. Drink it just as it is, straight from the tap.
Is it hard water, or does it smell like chlorine? An activated-carbon filter pitcher is the best everyday solution: it removes chlorine and reduces limescale. There’s just one rule: change the filter cartridge on time, or it will release what it has trapped. A home water softener treats hard water at the source, but that’s a whole other expense.
A special occasion or an exceptional tea party? A bottle that is «very lightly» or «lightly mineralized,» chosen based on its dry residue rather than its marketing. Save it for teas that deserve it: for everyday use, a carafe is more than enough.
One last tip, no matter what you choose: heat up freshly drawn water rather than reboiling the water left in the kettle, which results in a less flavorful cup. And keep in mind that water is only half the equation: its temperature and steeping time make up the other half, and we break these down tea by tea in our guide to steeping time.
Key Takeaways
- Water gentle (less than about 15 °F), chlorine-free and low in minerals makes the best cups.
- Soft tap water: perfect as is. Hard or chlorinated tap water: use a water filter pitcher.
- For bottled wine, read the dry residue at 180 °C : below 500 mg/L, ideally below 50 mg/L for delicate teas.
- Avoid: water high in minerals, distilled water, and water that has been reboiled.
- The blind taste test comparing tap water and filtered water is decided by a single cup.
FAQ: Water for Tea and Herbal Teas
Can you use tap water to make tea?
Yes, and it’s even ideal if it’s soft and low in chlorine. If it’s hard or smells like chlorine, a water filter pitcher can fix both problems for just a few cents per liter. A blind taste test with filtered water will tell you in just one cup which situation you’re in.
Which bottled water should you choose for tea?
Check the label for the dry residue at 180 °C and choose waters labeled «very low» or «low» in mineral content—terms defined by European regulations. Avoid waters labeled «rich in minerals»: their distinct taste overpowers that of the tea.
Why is there a film on the surface of my tea?
This is a telltale sign of hard water on black tea: the minerals in the water react with the compounds in the tea and form a thin film on the surface. It’s harmless, but revealing. Filtered or low-mineral-content water makes it disappear.
How can I remove the chlorine taste from water?
Chlorine is volatile: let the water sit in an open pitcher for about an hour before heating it, or pour it through a pitcher with an activated-carbon filter. Either method is sufficient to ensure your tea doesn't have an off-flavor.
Can you reboil the water from the kettle to make tea?
It’s best to avoid this: water that has been boiled several times results in a cup of tea that’s flatter and less vibrant. The right habit for tea lovers is simple: empty the kettle and start with fresh water for each pot of tea.