Water Chemistry / Brewing Water Calculator

The brewing water calculator adjusts a water chemistry profile by comparing a known source water against a target profile for a beer style, then computing the salt and acid additions needed to close the gap between them. It reports the resulting mineral concentrations in parts per million (ppm), along with residual alkalinity, total hardness, total alkalinity, and the chloride to sulfate ratio, the numbers that describe how a water profile will shape mash pH and flavor.

Source water is entered as Calcium, Magnesium, Sodium, Chloride, Sulfate, and Bicarbonate in ppm, either typed in directly from a water report or drawn from reference profiles such as Distilled/RO, Burton on Trent, Dublin, Pilsen, and Vienna, each representing a historically significant brewing water. Target profiles are keyed to beer style: Pale Ale, IPA, Pilsner, Stout, or Porter, or a custom target built from scratch.

Batch size, in gallons or liters, scales every addition's ion contribution, since ppm is a concentration and the same weight of salt produces a smaller effect in a larger volume of water. Each addition is one of nine salts and acids, Gypsum, Calcium Chloride, Epsom Salt, Table Salt, Baking Soda, Chalk, Pickling Lime, Lactic Acid (88 percent), or Phosphoric Acid (10 percent), entered by weight in grams or teaspoons, and each contributes a fixed set of ions per gram. Any number of additions can be combined in one profile, and each one's individual ion contribution is shown alongside the combined total, so the effect of a single salt can be isolated from the rest of the profile.

The chloride to sulfate ratio summarizes the balance between malt and hop character: below 0.5 favors hop bitterness, 0.5 to 0.8 is balanced bitter, 0.8 to 1.5 is balanced, 1.5 to 2.0 is balanced malty, and above 2.0 reads as very malty and sweet.

Settings holds the decimal precision for every output and a formula display that breaks down the calculation behind each derived property step by step.

Ion contributions per gram of salt dissolved in one gallon: Gypsum (CaSO₄·2H₂O) contributes 61.5 ppm Ca and 147.4 ppm SO₄; Calcium Chloride (CaCl₂) contributes 72 ppm Ca and 127 ppm Cl; Epsom Salt (MgSO₄·7H₂O) contributes 26 ppm Mg and 103 ppm SO₄; Table Salt (NaCl) contributes 104 ppm Na and 160 ppm Cl; Baking Soda (NaHCO₃) contributes 75 ppm Na and 191 ppm HCO₃; Chalk (CaCO₃) contributes 106 ppm Ca and 162 ppm HCO₃; Pickling Lime (Ca(OH)₂) contributes 143 ppm Ca and 122 ppm alkalinity; Lactic Acid (88 percent) reduces HCO₃ by 60 ppm per gram; Phosphoric Acid (10 percent) reduces HCO₃ by 70 ppm per ml. Total Hardness = 2.5 × Ca + 4.1 × Mg. Total Alkalinity = HCO₃ × 50 / 61. Residual Alkalinity = HCO₃ − (Ca / 3.5 + Mg / 7). All values are in ppm as CaCO₃ equivalents where applicable, and every addition scales linearly with batch size.

Water chemistry shapes hop expression, malt balance, and mash pH, so matching a water profile to a beer style is a routine step in serious recipe formulation. Small mineral adjustments change the chloride to sulfate balance that tilts a beer toward crisp bitterness or round maltiness.

• Pale Ale Brewing: A homebrewer starts with soft tap water (Ca 20, Mg 5, Cl 15, SO₄ 10) and wants a balanced pale ale profile. Targeting the Pale Ale profile and adding Gypsum and Calcium Chloride reaches Ca 100, Cl 75, SO₄ 150, a Cl:SO₄ ratio of 0.5 for a crisp, balanced bitterness.
• IPA Water Adjustment: A brewer using RO water (all ions zero) targets the IPA profile and adds Gypsum (8.5 grams) and Calcium Chloride (2 grams) to a 5 gallon batch, reaching final concentrations of Ca 133, Cl 51, SO₄ 251, with a Cl:SO₄ ratio of 0.2 that emphasizes hop bitterness and dryness.
• Pilsner Soft Water: Replicating Pilsen water for a Czech Pilsner means starting from distilled water and avoiding mineral additions, keeping every ion under 10 ppm, low residual alkalinity near zero, and minimal hardness, all suited to delicate malt expression.
• Stout and Porter: A dark beer calls for higher chloride and moderate bicarbonate. Targeting the Stout profile and adding Calcium Chloride (3 grams) and Baking Soda (1 gram) to 5.5 gallons pushes the Cl:SO₄ ratio past 2.0 for a smooth, malty character.
• Mash pH Control: High-bicarbonate tap water (HCO₃ 250) can be corrected with Lactic Acid (2 grams), which lowers HCO₃ and residual alkalinity, tracking the direction mash pH will move and helping avoid the high mash pH that extracts tannins from the grain.
• Recipe Development: Comparing salt additions against reference profiles such as Burton on Trent (high sulfate) versus Dublin (high bicarbonate) shows how each affects the final water chemistry and Cl:SO₄ balance during recipe formulation.