Coffee Shop Water Chemistry

Branch Street Coffee Roasters Water Specs:
Calcium: 80ppm
Magnesium 25ppm
Carbonate (KH) 55ppm

This falls into the “Ideal” brew zone according to the “Water For Coffee” book. Making these changes to our water allowed us to dial in our roasts to the ideal water chemistry and make our offerings more approachable to our target market and those who know about the importance of water chemistry.

To learn more about the ideal water chemistry, and how to achieve the target water, we highly recommend buying the book “Water For Coffee,” and learning about all the effects that different contaminants have.

These tests and solutions can be very complicated, so we do offer consultation for water conditioning and custom filtration recommendations. This can help ensure that you are able to get your water chemistry as close to the ideal zone as possible, allowing your coffee to stand out from the rest.

To test the concept of “perfect water” see the recipe below, and try a brew for yourself.


An excerpt from our infobook “Home Barista 101”

What’s In Your Water?


We touched briefly upon water quality and the importance of using the proper water for your coffee brewing.  Now let’s dive in a little deeper, and explore the chemistry of water, and the affect of water on coffee.  We will finish with a simple recipe to create the perfect water for coffee, and some alternate options that are available to you in a pinch.

By now, you probably have a pretty good idea of what coffee flavor’s key factor is: Extraction.  Water is one of the main ingredients, and it plays a major roll in the extraction process.

The chemistry of the water describes the chemical makeup of your water.  We are interested in three key chemicals: Calcium, Magnesium, and Bicarbonate.  These are what we consider to be the “active” molecules in the water.  Everything else is of secondary importance to extraction.

If you are on Youngstown City water (from Meander reservoir), you are most likely in luck.  The water chemistry is as close as you can get to perfect coffee water.  With a simple carbon filter (Britta, Pur, etc.) you can immediately begin brewing a great cup.

If you are on well water or another city water it is hard to tell without testing the water for these specific minerals.  Water filtration professionals do not usually carry the kits required to test for these minerals specifically, but water-testing kits can be purchased online for this exact task. There is an easier way!

You don’t have to crack ancient chemistry textbooks to solve this problem.  We are going to give you the perfect water, and it only takes a few minutes to make.

RECIPE: (From Matt Perger’s Barista Hustle)

  • WEIGH out 8.6 grams of Sodium Bicarbonate (baking soda)
  • WEIGH out 25 grams of Epsom salt (magnesium sulfate)
  • Add the ingredients above to 500 grams of DISTILLED water (not mineral water)


THIS IS YOUR CONCENTRATE not your brew water.  Keep this to make your brew water batches.

 Take 500 grams of distilled water, and add 2.5 grams of your concentrate to it.  BOOM! You just made the perfect water for coffee. 

The water recipe above requires a gram scale that reads to one decimal point, or 1/10 of a gram.  In the following section, we will go over scales and our recommendations for them.

In a pinch, try using “Spring Water” from a supermarket to brew the coffee.  Although not perfect, it is much better than using unknown water, and will likely be more similar to our target water chemistry.



The perfect water chemistry has a range, but the simplest target is a General Hardness (GH) of 100ppm, and a Carbonate Hardness (KH) of 50ppm.

General Hardness (GH) is described as the sum of Calcium and Magnesium.  GH testing kits can be inaccurate, as they sometimes are sensitive to other minerals dissolved in water.  To calculate your true GH, you need separate titration kits to test for Calcium and Magnesium, and then add those results together.

Carbonate Hardness (KH) is the buffering ability of the water.  This reacts with the acids in your coffee, and not always in a good way.  Too much KH can make the coffee taste ashy, chalky or bland.

As easy as it is to make the ‘perfect water’ from the recipe above, why not make sure that you are getting the best cup from the specialty coffee you brought home??