Brewing water
Dublin water
Hard and strongly alkaline, with very high bicarbonate — well matched to the acidity of heavily roasted grain.
Dublin, Ireland
Read this as a reconstruction. Figures are the widely-reproduced historical analysis, stored as a range because the underlying supply varied by well, by season and over time. Treat them as an indication of relative character, not as a specification to dose water against.
Mineral content
| Ion | mg/l | What it does |
|---|---|---|
| Calcium (Ca²⁺) | 90–150 ppm | Lowers mash pH, supports enzyme and protein behaviour, aids yeast flocculation and clarity. Close to flavour-neutral itself. |
| Magnesium (Mg²⁺) | 2–10 ppm | A yeast nutrient in small amounts. Above roughly 30 mg/l it begins to read as sour or metallic. |
| Sodium (Na⁺) | 8–20 ppm | Rounds and accentuates sweetness at moderate levels. With high sulphate it turns harsh rather than full. |
| Chloride (Cl⁻) | 12–30 ppm | Tends to accentuate malt fullness, body and roundness. A tendency in perception, not an additive sweetness. |
| Sulphate (SO₄²⁻) | 40–70 ppm | Tends to accentuate hop bitterness and drive a drier finish. At high levels it reads as harsh and minerally rather than simply more bitter. |
| Bicarbonate (HCO₃⁻) | 250–400 ppm | The alkalinity that resists mash acidification. High bicarbonate needs dark, acidic malt to balance it — which is why alkaline-water cities brewed dark beer. |
Overall hardness: hard. Balance: sulphate leaning (chloride:sulphate roughly 0.38:1). The ratio is a shorthand the trade finds useful for describing whether a water pushes a beer toward crispness or fullness. It is not a formula, and two waters with the same ratio at very different total concentrations do not behave alike.
Historical context
Very high alkalinity needs acidity to balance it, and roasted barley supplies exactly that. The pairing is mutual: the water suits the grain, and the grain makes the water workable.
Styles associated with this water
Association, not causation. Brewers selected recipes that worked with the water available to them; the water did not design the beer.
Other water profiles
- Balanced reference profile — moderately hard, balanced.
- Burton-on-Trent water — very hard, strongly sulphate.
- Dortmund water — hard, sulphate leaning.
- Edinburgh water — hard, sulphate leaning.
- London water — moderately hard, balanced.
- Munich water — moderately hard, balanced.
- Pilsen water — very soft, balanced.
- Vienna water — hard, sulphate leaning.
Last reviewed 2026-08-15.
Evidence
What BeerHQ knows about this, and how. Every statement carries the state of the evidence behind it rather than being presented flatly as fact.
High-bicarbonate water resists the acidification that occurs when malt meets water, and needs the acidity of roasted and crystal malt to reach a workable mash pH — which is why alkaline-water cities historically brewed dark beer successfully and pale beer badly.
Backed by a source
Sources: Water: A Comprehensive Guide for Brewers — print; Brewing: Science and Practice — print