Water
Water dilution and blending
Half tap, half reverse osmosis: here is what you get, ion by ion. And the share of reverse osmosis water needed to hit your target.
Result
Fill in the values and run the calculation, or try the example.
This is the calculation Krausi uses. Create an account to save it in a recipe or a brew.
Create my accountWhy dilute your brewing water?
When a water carries too many minerals, the simplest thing is to cut it with a mineral-free water: reverse osmosis water, demineralised water or a very low-mineral spring water. No product to dose, no risk of off-flavours.
Dilution lowers every ion at the same time. It is ideal for bringing down bicarbonate that is too high before a pale beer. Afterwards, if needed, you add back the calcium or sulphate that is missing.
The same calculation is used to blend any two waters, for example tap water and a bottled water.
How is the blend profile calculated?
Each ion in the blend is the average of the two waters, weighted by the volumes:
concentration = (V1 × C1 + V2 × C2) / (V1 + V2)If you enter an ion and a target value, the tool also calculates the share of reverse osmosis water needed to bring water 1 to it:
share of RO water = 1 − target / concentration of water 1Worked example
Values entered
- Profile of water 1 (tap water) in mg/L: calcium in mg/l (ppm) 80, magnesium in mg/l (ppm) 10, sodium in mg/l (ppm) 15, sulphate in mg/l (ppm) 60, chloride in mg/l (ppm) 30, bicarbonate in mg/l (ppm) 300
- Volume of water 1 in litres: 10
- Profile of water 2 in mg/L: calcium in mg/l (ppm) 0, magnesium in mg/l (ppm) 0, sodium in mg/l (ppm) 0, sulphate in mg/l (ppm) 0, chloride in mg/l (ppm) 0, bicarbonate in mg/l (ppm) 0
- Volume of water 2 in litres: 10
- Ion to adjust by dilution: Bicarbonate (HCO3)
- Target concentration for this ion, in mg/L: 100
Result from the tool
- Profil: mg/L (ppm)
- 40
- Profil: mg/L (ppm)
- 5
- Profil: mg/L (ppm)
- 7.5
- Profil: mg/L (ppm)
- 30
- Profil: mg/L (ppm)
- 15
- Profil: mg/L (ppm)
- 150
- Share of reverse osmosis water in the blend to reach the target, in %
- 66.67 %
What the tool does not do
- Dilution is linear: it does not account for chalk precipitating during the boil.
- Diluting also lowers calcium: add some back with gypsum or calcium chloride if the blend drops below 50 ppm.
- The share of reverse osmosis water is calculated for a mineral-free water 2.
Frequently asked questions
Can I brew with pure reverse osmosis water?
Not without adding salts: without calcium, the enzymes work poorly and the yeast lacks minerals. Start from reverse osmosis water, then rebuild a profile with the brewing salts calculation.
Spring water or tap water?
Both are fine if their profile is known. A very low-mineral spring water can replace reverse osmosis water for diluting. Avoid mineral waters rich in bicarbonate or sodium.
And with the assistant?
Ask Krausi the same question in plain language: he picks this tool, does the calculation and files the result in your project.
My tap water has 300 of bicarbonate. I want to get down to 100 for a pils.
You need 67% reverse osmosis water: for 30 L, blend 10 L of tap water and 20 L of reverse osmosis water. Calcium drops in the same proportion: remember to add some back with a little gypsum or calcium chloride.