Water blending
Cut your tap water with distilled or RO water. Choose a ratio and see the result, or name a target for one mineral and get the ratio that hits it.
Why blend
If your tap water is too hard or too alkaline for a pale beer, diluting it is the simplest fix: every mineral drops in proportion. It's cheaper than going all-RO and keeps some of the character of your local water.
Notes
- Blending is a straight mass balance: blend = tap share × tap + diluent share × diluent, for every ion. Solving for one ion: tap share = (target − diluent) ÷ (tap − diluent). The answer is exact for the numbers you enter; it can only land between the diluent and tap values.
- Utility reports are often annual averages and can differ from what's in your tap today, especially where the supply switches sources seasonally. A recent lab test is more reliable. Remove chlorine or chloramine (for example with a campden tablet) whatever you blend.
- Distilled water is effectively zero for all of these. RO output usually carries a little of everything — often single-digit to low double-digit mg/L, depending on the membrane and your source water. If you have a reading, enter it.
- Alkalinity is mg/L as CaCO₃; bicarbonate = alkalinity × 1.22. Homebrewing beer for personal use is legal federally in the US; check your state and local laws.