A brewing water calculator determines what mineral salts to add to your brewing water to match a target profile for a specific beer style. Water chemistry is one of the most impactful and underused tools in homebrewing — adjusting calcium, sulfate, and chloride levels can dramatically change how your beer tastes. This free tool replaces spreadsheets like Bru'n Water with an instant web-based profile calculator.
Batch Setup
Source Water Profile
Enter minerals in ppm (mg/L). All fields default to 0 for RO/distilled water.
Target Water Profile
Salt Additions
| Salt | Formula | Amount (g) | Primary effect |
|---|
Resulting vs Target Profile (ppm)
| Mineral | Source | Added | Result | Target | Diff |
|---|
Salt additions are calculated to bring source water to target profile. Negative additions mean source already exceeds target — consider diluting with RO water. All values are estimates; actual results vary with measurement precision.
Water Profile Reference by Beer Style
| Style | Ca | Mg | Na | Cl | SO₄ | HCO₃ | Character |
|---|---|---|---|---|---|---|---|
| Pilsner / Lager | 7 | 3 | 3 | 5 | 10 | 25 | Very soft, delicate, clean |
| Pale Ale | 100 | 10 | 10 | 75 | 150 | 50 | Crisp, hop-forward |
| IPA | 130 | 10 | 10 | 50 | 250 | 25 | Dry, bitter, assertive hops |
| Stout / Porter | 100 | 12 | 50 | 150 | 50 | 150 | Round, roasty, full-bodied |
| Amber / Red Ale | 80 | 10 | 15 | 100 | 75 | 75 | Balanced malt and hops |
| Wheat Beer | 50 | 8 | 10 | 75 | 50 | 100 | Soft, fruity, easy-drinking |
| Belgian | 60 | 8 | 15 | 60 | 40 | 80 | Spicy, fruity esters, complex |
How to Use the Brewing Water Calculator
Water chemistry is the most underused variable in homebrewing. The mineral content of your water — particularly calcium, sulfate, and chloride — directly affects mash pH, hop bitterness perception, malt sweetness, and yeast health. This free brewing water calculator takes your source water profile, compares it to a target style profile, and calculates exactly how many grams of each mineral salt to add to bridge the gap.
Step 1: Set your batch volume and units
Enter your batch volume in gallons or liters. This is the total volume of water you are treating — typically your pre-boil volume including mash and sparge water combined, or just the mash volume if you treat separately. Choose whether to display salt additions in grams, ounces, or teaspoons. Grams are the most precise; a digital kitchen scale accurate to 0.1g is strongly recommended for water chemistry.
Step 2: Enter your source water profile
Enter your source water mineral concentrations in ppm (mg/L). Use a built-in preset to get started — RO / Distilled sets all values to zero for a blank-slate approach, while city water presets give typical ranges for soft, moderate, and hard municipal water. To find your actual tap water profile, contact your local water utility for an annual water quality report (often available on their website). For well water, have it tested by a laboratory.
Step 3: Select your target beer style
Choose a beer style from the target profile dropdown or enter a custom target. The style presets load typical mineral targets for that style: Pilsner loads very soft numbers close to the famous Pilsen source water, IPA loads high sulfate for assertive hop dryness, and Stout loads higher sodium and chloride for the round, full mouthfeel associated with Dublin water. You can fine-tune any value after selecting a preset.
Step 4: Review the salt additions
The results table shows how much of each salt to add to your batch: Gypsum (CaSO₄) raises calcium and sulfate for hop crispness; Calcium Chloride (CaCl₂) raises calcium and chloride for malt roundness; Epsom Salt (MgSO₄) adds magnesium and sulfate; Table Salt (NaCl) adds sodium and chloride; Baking Soda (NaHCO₃) raises alkalinity and sodium, useful for dark beers; Chalk (CaCO₃) raises calcium and bicarbonate but dissolves poorly — baking soda is often preferred. If a value is negative, your source water already exceeds the target for that mineral and you should dilute with RO water.
Understanding the Cl:SO₄ ratio
The chloride-to-sulfate ratio is a practical shorthand for perceived beer balance. A ratio above 1 (more chloride) promotes malt sweetness and fullness — ideal for stouts, ambers, and wheats. A ratio below 1 (more sulfate) promotes hop dryness and crispness — ideal for IPAs and pale ales. Neither extreme is better; it depends on the style you are brewing. The results display both the resulting ratio from your additions and the target ratio from your chosen style.
All calculations run locally in your browser. No brewing data is transmitted or stored. Bookmark this page for easy access on brew day.
Frequently Asked Questions
Is this brewing water calculator really free?
Yes, completely free with no account or signup required. All calculations happen in your browser using JavaScript. No brewing data, recipes, or water profiles are sent to any server.
Is my brewing data safe and private?
Absolutely. Every calculation runs locally in your browser. Your source water minerals, batch size, and recipe details never leave your device. You can even use this tool offline after the page loads.
Why does water chemistry matter in brewing?
Water is the largest ingredient in beer by volume. The mineral content of your water affects mash pH, enzyme activity, hop bitterness perception, malt character, and yeast health. Soft water tends to produce rounder, maltier beers while sulfate-rich water emphasizes hop dryness. Matching your water to the style being brewed is one of the biggest levers for improving beer quality.
What does each mineral do to beer flavor?
Calcium (Ca) supports enzyme activity and yeast health. Magnesium (Mg) adds a slightly harsh bitterness in high amounts. Sodium (Na) enhances malt roundness and sweetness. Chloride (Cl) accentuates malt fullness. Sulfate (SO4) accentuates hop dryness and bitterness. Bicarbonate (HCO3) raises mash pH, important for dark roasted malts that naturally acidify the mash.
What is RO or distilled water and why start with it?
Reverse osmosis (RO) and distilled water contain essentially no minerals — they are a blank slate. Starting with RO or distilled water lets you build your mineral profile from scratch with precision, adding exactly what each style needs. Many homebrewers use RO water to avoid the variability of tap water.
How accurate are the salt addition calculations?
The calculations use established ion contribution values per gram of salt per gallon (or liter), which are widely used in homebrewing software like Bru'n Water and Brewfather. Results are accurate to within a few ppm for typical batch sizes. Small measurement errors in weighing salts are the primary source of real-world deviation.
What is the Cl:SO4 ratio and why does it matter?
The chloride-to-sulfate ratio is a quick guide to a beer's perceived balance. A ratio above 1 (more chloride) emphasizes malt roundness and is typical for stouts, ambers, and wheat beers. A ratio below 1 (more sulfate) emphasizes hop dryness and is typical for IPAs and pale ales. Exact balance varies by style and brewer preference.
Can I use this for both all-grain and extract brewing?
Yes. The calculations apply to the full batch volume regardless of method. For extract brewing, note that most malt extracts already contain minerals from their source water. If using extract, consider targeting a lower mineral addition since the extract contributes some baseline mineral content.