Water & Mineral
Guide
"Water is not just a solvent; it is a catalyst. It creates the stage upon which malt enzymes dance and hop oils perform."
The Forgotten Ingredient
When embarking on the art of home brewing, one ingredient often overlooked is water. Yet, it constitutes over 90% of your beer. Its quality and mineral content play a pivotal role in defining the final taste, aroma, and mouthfeel of the beer.
Water is an active participant. It influences the efficiency of the mash, the extraction of hop bitterness, and the flocculation of yeast. Mastering water is what distinguishes an average brew from an exceptional one.
The Ionic Cast
Calcium, Magnesium, and Sodium
Calcium (Ca²⁺) The Workhorse
Target: 50–150 ppm
Calcium is the most critical mineral in brewing. It reacts with phosphates in the malt to lower mash pH, creating the optimal environment for amylase enzymes. It also promotes protein coagulation (hot break), reduces beerstone, and is essential for yeast flocculation.
⚡ Magnesium (Mg²⁺)
A vital yeast nutrient at low levels (10–30 ppm). It acts as a co-factor in yeast metabolism, specifically helping with the production of ATP (energy). However, in excess (>50 ppm), it contributes a sharp, metallic bitterness (often described as "sour-bitter") and acts as a laxative. Pro Tip: Malt already contains significant Magnesium; you rarely need to add Epsom salts unless using 100% Reverse Osmosis water.
🌊 Sodium (Na⁺)
The flavor rounder. Like salt in cooking, it accentuates sweetness and maltiness at low levels (10–70 ppm). It is crucial for Gose styles. However, above 150 ppm, it becomes harsh and salty. It clashes violently with high Sulfate levels, creating a harsh, scraping bitterness known as the "minerality clash."
The Source
Tap vs. RO vs. Well
Before you add salts, you must understand your starting point. You cannot build a recipe on a shaky foundation.
- Reverse Osmosis (RO) / Distilled: The "Blank Canvas." This water has almost zero mineral content. It is perfect for brewing because it allows total control. You create the exact profile you want by adding salts.
- Municipal Tap Water: Often suitable, but carries a hidden enemy: Chloramine. Unlike Chlorine, Chloramine does not boil off. When Chloramine reacts with malt phenols, it creates Chlorophenols—compounds that taste like plastic, band-aids, or antiseptic mouthwash. You must treat tap water with a Carbon Filter or Campden tablets (Potassium Metabisulfite) to break this bond.
- Well Water: Highly variable. It can be excellent, but often contains high levels of Iron (metallic blood taste) or Manganese. Always get a lab report before brewing with well water.
pH & Alkalinity
The Concept of Residual Alkalinity
Bicarbonate (HCO₃⁻) The Buffer
Bicarbonate acts as a buffer, resisting the natural drop in pH during the mash. This is defined by Residual Alkalinity (RA).
The Dark Malt Effect: Roasted malts (like Roasted Barley or Black Patent) are naturally acidic due to Maillard reaction products created during roasting. If you brew a Stout with soft water (low alkalinity), the acidity of the malt will crash your mash pH below 5.2, resulting in a thin, sour, acrid beer. You need alkalinity (Bicarbonate) to buffer this acid.
Conversely, with Pale malts, there is no roast acid. If you have high alkalinity, the pH will stay too high (>5.6), causing tannin extraction (astringency) and poor enzyme activity.
Pale Beer Strategy
Low RA Required. Keep Bicarbonate low (<50 ppm). Use acid or RO water to reduce alkalinity.
Dark Beer Strategy
High RA Required. Target higher Bicarbonate (100–200 ppm) or use Baking Soda to neutralize the roast acidity.
Acidification
Lactic vs Phosphoric & The Sparge
Sometimes, calcium additions aren't enough to hit that magic pH of 5.2-5.4. You need direct acidification.
- Lactic Acid (88%): The homebrew standard. Easy to use, organic. However, in high concentrations, it can impart a slight "tang" or yogurt-like flavor (lactate).
- Phosphoric Acid (85%): Preferred by commercial breweries. It is completely flavor-neutral even at higher doses, making it ideal for delicate lagers where the lactic tang might be noticeable.
- Acidulated Malt: A German solution. Malt sprayed with lactic acid. Useful for adhering to the Reinheitsgebot, but harder to control precisely than liquid acids.
As you rinse the grains (sparge), the buffering power of the malt decreases. If your sparge water is alkaline (pH > 7.0) and hot (>170°F), the pH of the grain bed will rise above 6.0. This triggers the extraction of polyphenols (tannins) and silicates from the grain husks, resulting in a permanent haze and a harsh, astringent bitterness. Always acidify your sparge water to pH 5.5-6.0!
The Flavor Lever
Sulfate to Chloride Ratio Dynamics
The Ratio Rule
This is the single most powerful tool in water adjustment. Sulfate (SO₄²⁻) enhances bitterness, making it crisp, dry, and assertive. Chloride (Cl⁻) enhances malt, adding body, sweetness, and a "pillowy" texture.
Historical Profiles
Geography is Destiny
Pilsen, Czech Republic
Extremely Soft. Almost zero mineral content (Calcium <10ppm). This lack of buffering capacity meant local brewers could not use dark malts (which would crash the pH). They were forced to invent the golden Pilsner using pale malt.
Burton-on-Trent, UK
Burton-on-Trent, UK
Extremely Hard. Massive Sulfate levels (up to 800ppm!). This creates the famous "Burton Snatch"—a sulfurous, dry, crisp finish that defined the English Pale Ale and IPA. It accentuates hop bitterness aggressively.
Dublin, Ireland
High Alkalinity. High Bicarbonate (300ppm+). This water is terrible for pale beers but perfect for Stout. The high alkalinity buffered the acidity of the Roasted Barley, creating a smooth Dry Stout instead of an acidic mess.
The Toolkit
Adjustments, Salts, and Common Mistakes
🧪 The Salts
- Gypsum (CaSO₄): Adds Calcium + Sulfate. Increases crispness.
- Calcium Chloride (CaCl₂): Adds Calcium + Chloride. Increases softness.
- Baking Soda (NaHCO₃): Adds Sodium + Bicarbonate. Raises pH for dark beers.
- Epsom Salt (MgSO₄): Adds Magnesium + Sulfate. Use sparingly.
⚠️ Common Pitfalls
- Overcorrecting: "Fixing" water without tasting. Too much sulfate tastes metallic; too much chloride tastes muddy.
- Ignoring the Source: You cannot adjust what you don't measure. Use a water testing kit.
- Zinc Confusion: Zinc Sulfate is a yeast nutrient, not a water salt. Do not confuse it with Gypsum! Zinc helps yeast budding, Gypsum helps hop crispness.
Filtration is the First Step
Before adding salts, you must remove the bad stuff. Chlorine and Chloramine react with malt phenols to create plastic/medicinal off-flavors. Always use a Carbon Filter or Campden tablets to neutralize municipal sanitizers.
© 2026 Brewing Architecture Series // Chemistry Series Technical Vol. V