Why does water chemistry matter in brewing?

Water chemistry affects mash pH, hop bitterness perception, and overall beer character. The sulphate-to-chloride ratio is particularly important: higher sulphate accentuates hop bitterness, while higher chloride emphasises malt sweetness and fullness.

What is the sulphate-to-chloride ratio?

The SO4:Cl ratio determines perceived balance. Ratio > 2:1 = hop-forward. Ratio 1:1 = balanced. Ratio < 1:2 = malt-forward. IPAs typically use 2:1 to 3:1, while malty styles use 1:2.

Should I add salts to mash or sparge water?

Adding all salts to the mash water affects mash pH directly. A common split is 60% to the mash and 40% to the sparge. This calculator lets you set that split in Advanced Options.

Should I start from RO or distilled water?

Starting from RO or distilled water gives you a clean slate and full control. If using tap water, get a water report from your utility and use the Custom source option to subtract existing mineral levels.

How much gypsum is too much?

Keep calcium below 150 ppm, sulphate below 300 ppm, and chloride below 200 ppm. Excessively high mineral levels can give harsh, mineral-like flavours. Start conservative and adjust based on taste.

BrewCalcs

Water Chemistry Calculator — Adjust Brewing Water Profile

Calculate mineral salt additions for target water profiles with source water adjustment.

Source Water

Target Profile

Batch Volume

Volume measurement

How We Calculate This

Water Chemistry Adjustment

This calculator works out the difference between your source water minerals and target profile, then calculates salt additions to bridge the gap. Each salt contributes specific ions:

Gypsum (CaSO4): adds calcium and sulphate — emphasises hop bitterness
Calcium Chloride (CaCl2): adds calcium and chloride — emphasises malt sweetness
Epsom Salt (MgSO4): adds magnesium and sulphate — secondary sulphate source
Baking Soda (NaHCO3): adds sodium and alkalinity — for dark beer styles

Frequently Asked Questions

Related Calculators

Strike Water Calculator

Calculate strike water temperature for your target mash temperature.

Mash Temperature Calculator

Determine resulting mash temperature from grain and water inputs.

Water Volume Calculator

Calculate total water needed including mash, sparge and losses.

Sparge Water Calculator

Calculate sparge water volume for your batch size and grain bill.

pH Adjustment Calculator

Calculate acid or base additions to hit your target mash pH.

Last updated: February 2026

All calculations are estimates. Always verify values and adjust based on your equipment and ingredients.