Water Mixing Calculator

Build brewing water from distilled water and two pantry concentrates. Pick a recipe or drag the point on the map, and weigh out exactly what the batch needs.

Mineral map

Recipe

Drag or tap to move the point, or select it and use the arrow keys.

ppm
ppm
L

To make 1 litre

  1. Tare an empty bottle on the scale.
  2. 8.0g hardness concentrate
  3. 4.0g buffer concentrate
  4. 1,000g top up with distilled water to this total, then shake
Total dissolved solids
about 163 ppm
SCA range
75–250 ppm

Close to the SCA targets. Flatters every brewer and roast.

How to make the two concentrates
  • Hardness concentrate: dissolve 24.6 g of plain Epsom salt in 1,000 g of distilled water.
  • Buffer concentrate: dissolve 16.8 g of baking soda in 1,000 g of distilled water.

Each gram of either, added to a litre, adds about 10 ppm. More in DIY coffee water.

How it works

Brewing water changes extraction, clarity, and perceived acidity. This calculator helps you build repeatable water from distilled water and mineral concentrates instead of relying on inconsistent tap water.

  • Target SCA-style or roast-specific water profiles.
  • Calculate concentrate additions for any batch size.
  • Use custom mineral goals when you want to tune for a specific coffee.

  1. Set the total water volume you need

    Choose enough brewing water for a single session or for a larger prep batch.

  2. Pick a profile or enter custom mineral targets

    The profile sets how many grams of each concentrate go into the batch.

  3. Mix carefully and label your batch

    Consistent labeling makes it much easier to compare how different water profiles affect the same coffee.

Questions

Why not just use tap water?

Some tap water is excellent, but mineral content can change by area or season. Mixing your own water gives you a stable baseline.

What do hardness and TDS do in coffee brewing?

They influence extraction, buffering, body, and flavor clarity. Different coffees can taste brighter, sweeter, or flatter depending on the mineral balance.

Do I need distilled water for this calculator?

That is the cleanest starting point because it removes unknown minerals. If you start with mineralized water, the final profile will be less predictable.

What water profile is best for light roasts?

Many brewers prefer lower-buffer, lower-hardness profiles for light roasts because they can preserve brightness and clarity, but the ideal profile still depends on the coffee.