Coffee Brew Water Mineral Calculator

Brew Water Mineral Calculator

Transform distilled water into championship-level brewing water.

Why calculate? Water makes up 98% of your coffee. If your water is too pure (distilled), your coffee will taste flat and empty. If it’s too hard (tap), it will taste chalky or muted. By adding precise minerals to empty water, you can control the flavor extraction.

*Use distilled or Reverse Osmosis (RO) water as your base.

ADD TO YOUR WATER:

Baking Soda Sodium Bicarbonate (NaHCO₃) Controls Acidity/Buffer
0.00g
Epsom Salt Magnesium Sulfate (MgSO₄) Enhances Flavor/Extraction
0.00g

Visualizing Your Water Profile

This chart shows how your selected profile balances Hardness (Magnesium) against Alkalinity (Bicarbonate).

SOUR / SHARP
CHALKY / HEAVY
EMPTY / THIN
SWEET / BALANCED
BUFFER (Alkalinity) →
HARDNESS (Mg) →

The Science of Water: Definitions

To control your brew, you need to understand the two main levers we pull when adding minerals.

Component Common Name Role in Coffee
General Hardness (GH) Magnesium / Calcium The “claw.” These mineral ions bond to flavor compounds in the coffee grounds and pull them into the water.
Too low = Weak flavor. Too high = Metallic/Bitter.
Alkalinity (KH) Bicarbonate (Buffer) The “shield.” It neutralizes the natural acids in coffee. It regulates pH stability.
Too low = Sour/Vinegar. Too high = Chalky/Flat.

How to Use (Step-by-Step)

1

Source Your Base

Buy Distilled Water or Reverse Osmosis water. It must have a TDS (Total Dissolved Solids) close to 0 ppm. Do not use tap water.

2

Get Your Minerals

You need pure Baking Soda (Sodium Bicarbonate) found in any grocery store, and Epsom Salt (Magnesium Sulfate), usually found in the pharmacy aisle (ensure it is unscented and food safe).

3

Calculate & Weigh

Use the calculator above. Enter your container size (e.g., 1 Gallon). Weigh the output powders on a precise scale (0.01g accuracy recommended).

4

Dissolve

Add the powders to your water jug. Shake vigorously. It may take a few hours for the minerals to fully dissolve and stabilize.

5

Brew

Use this water in your kettle. Taste the difference! If it tastes too dull, try the “Bright” profile next time.

Manual Calculation Guide

If you prefer to do the math yourself or want to create concentrates, here are the simplified factors used by baristas globally (Barista Hustle method).

The Golden Formulas:

  • Buffer: 1g Baking Soda into 1L water adds ~600ppm Alkalinity (KH).
  • Hardness: 1g Epsom Salt into 1L water adds ~400ppm Hardness (GH).

To hit a target of 40ppm Alkalinity in 5 Liters:
(40 target ÷ 600 factor) × 5 Liters = 0.33g Baking Soda.

Frequently Asked Questions

Can I just use filtered tap water?
Generally, no. This calculator adds minerals to Zero water. Tap water already contains unknown amounts of calcium, magnesium, and carbonate. If you add these minerals to tap water, you will likely get extremely hard water that scales up your machine and ruins the coffee flavor.
Why no Calcium Chloride?
Many advanced recipes use Calcium Chloride. However, Calcium can cause limescale (calcium carbonate) buildup in espresso machine boilers. Magnesium (Epsom Salt) does not form scale as easily and is generally considered to add a sweeter, fruitier flavor profile compared to Calcium’s “creamy” profile. For safety and simplicity, this tool uses Magnesium.
My scale only measures 1 gram increments. What do I do?
You cannot measure 0.2g on a kitchen scale. You have two options:
  1. Make a Concentrate: Mix 10g of mineral into 100g of water. Now, 10g of that liquid contains 1g of mineral. This is easier to weigh.
  2. Make a larger batch: Instead of making 1 liter of brew water, make 5 Gallons. The mineral amounts will be large enough to weigh on a standard kitchen scale.
How long does the water last?
If stored in a clean, food-safe container out of direct sunlight, mineralized water can last for months. Just give it a shake before using it to ensure minerals haven’t settled at the bottom.