Brewed coffee is roughly 98% water, so the water you use changes the taste more than most people expect. Minerals in water — mainly calcium and magnesium — help pull flavour out of the coffee, while bicarbonate (alkalinity) buffers acidity. Too few minerals and coffee tastes flat or sharply sour; too many and it tastes chalky and dull, and your kettle and machine fill with scale.
What the SCA recommends
| Measure | Target | Acceptable range |
|---|---|---|
| Total dissolved solids (TDS) | 150 mg/L | 75–250 mg/L |
| Calcium hardness (as CaCO₃) | ≈ 70 mg/L | 50–175 mg/L (≈ 3–10 °dH) |
| Total alkalinity | 40 mg/L | 40–70 mg/L |
| pH | 7.0 | 6.5–7.5 |
| Chlorine / odour | None | Clean and odour-free |
Water in Norway
Much of Norway's tap water comes from lakes and surface water and is soft — often well below 3 °dH — and low in alkalinity. That's great for your kettle (almost no scale) but can make light-roast coffee taste thin or overly sour. You can look up your water's hardness on your municipality's (kommune) drinking-water page. Harder water is more common in some areas with limestone bedrock. 1 °dH equals about 17.8 mg/L of hardness as CaCO₃.
How to get better brewing water
Start with cold, fresh tap water
Run the tap until it's cold and boil fresh water each time. Re-boiled water and hot-tap water taste stale.
Remineralise soft water
Mineral sachets or drops made for coffee, added to distilled or very soft water, give you SCA-style water in seconds and a more rounded cup.
Filter hard water
A jug filter removes chlorine taste and some hardness. It's most useful where water is hard or tastes of chlorine.
Read bottled-water labels
If you use bottled water, pick still water with moderate minerals (around 75–250 mg/L dissolved solids) and low sodium. Never brew with distilled water on its own — it tastes flat.
Water FAQ
Is tap water good for coffee?
Usually, yes — especially if it tastes clean and has no chlorine smell. Very soft or very hard water can be improved with minerals or a filter.
Why does my coffee taste sour with soft water?
Soft water has little bicarbonate to buffer coffee's acids and few minerals to extract sweetness, so acidity stands out. Remineralising or grinding a little finer helps.
What temperature should brewing water be?
90–96 °C for most methods. Use the hotter end for light roasts and a little cooler for dark roasts.