How the additions are calculated
Each salt releases its ions in fixed proportions. The share of an ion in a salt follows from the molar masses:
where is the weight of salt in grams, the water volume in liters, the number of ions per formula unit, the molar mass of the ion and that of the salt, including any water of crystallization. The molar masses come from the standard atomic weights.
For example, 1 g of gypsum (CaSO₄·2H₂O) in 1 L adds about 233 ppm of calcium and 558 ppm of sulfate; in a US gallon, about 61 ppm of calcium.
Starting from water with 20 ppm of calcium, 15 ppm of chloride, 20 ppm of sulfate and 60 ppm of bicarbonate, adding 5 g of gypsum and 3 g of calcium chloride to 30 L gives about 86 ppm of calcium, 113 ppm of sulfate and 63 ppm of chloride, a sulfate-to-chloride ratio of 1.8 and a residual alkalinity of about −15 ppm as CaCO₃.
Bicarbonate is reported as alkalinity with a factor of about 50/61, which holds for typical brewing water. Chalk and pickling lime count as the bicarbonate they form once dissolved.
Inside Foambyte, water profiles keep your source water, and each recipe’s water settings add the brewing salts you plan to use.
Reference tables
| Salt | Ca | Mg | Na | Cl | SO₄ | HCO₃ |
|---|---|---|---|---|---|---|
| Gypsum (CaSO₄·2H₂O) | 232.8 | — | — | — | 557.9 | — |
| Calcium chloride (CaCl₂·2H₂O) | 272.6 | — | — | 482.3 | — | — |
| Epsom salt (MgSO₄·7H₂O) | — | 98.6 | — | — | 389.7 | — |
| Magnesium chloride (MgCl₂·6H₂O) | — | 119.6 | — | 348.8 | — | — |
| Table salt (NaCl) | — | — | 393.4 | 606.6 | — | — |
| Baking soda (NaHCO₃) | — | — | 273.7 | — | — | 726.3 |
| Chalk (CaCO₃) | 400.4 | — | — | — | — | 1,219.3 |
| Pickling lime (Ca(OH)₂) | 540.9 | — | — | — | — | 1,647.0 |
| Salt | Ca | Mg | Na | Cl | SO₄ | HCO₃ |
|---|---|---|---|---|---|---|
| Gypsum (CaSO₄·2H₂O) | 61.5 | — | — | — | 147.4 | — |
| Calcium chloride (CaCl₂·2H₂O) | 72.0 | — | — | 127.4 | — | — |
| Epsom salt (MgSO₄·7H₂O) | — | 26.1 | — | — | 103.0 | — |
| Magnesium chloride (MgCl₂·6H₂O) | — | 31.6 | — | 92.1 | — | — |
| Table salt (NaCl) | — | — | 103.9 | 160.2 | — | — |
| Baking soda (NaHCO₃) | — | — | 72.3 | — | — | 191.9 |
| Chalk (CaCO₃) | 105.8 | — | — | — | — | 322.1 |
| Pickling lime (Ca(OH)₂) | 142.9 | — | — | — | — | 435.1 |
Sources
- Commission on Isotopic Abundances and Atomic Weights (CIAAW). “Abridged Standard Atomic Weights 2024”, ciaaw.org, 2024. Atomic weights of H, C, O, Na, Mg, S, Cl and Ca, from which the molar masses of the salts and their ion shares are calculated.
- Thomas Prohaska et al.. “Standard atomic weights of the elements 2021 (IUPAC Technical Report)”, Pure and Applied Chemistry 94 (5), 573–600, 2022. The report the CIAAW table is based on, cited as CIAAW asks.
- Kai Troester. “The effect of brewing water and grist composition on the pH of the mash”, braukaiser.com, 2009. Finding that undissolved chalk raises mash pH far less than dissolved chalk. The paper is licensed CC BY-NC 3.0; none of its text, tables or figures are reproduced here.