Hard Or Soft? Which Is The Best Water For Your Coffee?

Have you ever been to your local coffee shop and had an absolute hall-of-fame cup of coffee, purchased some of their beans for home brewing, gone through the exact same extraction process, only to find the coffee is flat, hollow, bitter or just not right?

It would be easy to blame your machine, grind, or even decide the bean was a one-hit-wonder and isn't that good after all… but have you ever considered it could be the water?

Coffee is made up of at least 60% water, and could even be up to 98% water. Despite being a clear liquid, there are a lot of solids in water that can affect your brewing method, especially when sourced from the tap. So, what do you do? Let’s put our goggles on and dive into finding the best water for your coffee!

So, what’s in water, aside from H2O?

  • Minerals and other organic substances from the soil
  • Water treatment chemicals i.e chlorine, which is added to the main water pipes to maintain microbiological quality standards
  • Substances from the water supply system like copper and iron residues
  • Microbes – harmless ones, but also germs

There are two very important components to water when it comes to coffee:

  1. Mineral Ions: 
Calcium and Magnesium are important minerals to help with the extraction of flavour from your coffee. Not enough, and your extraction is empty and plain. Too many minerals will result in heavy and over-extracted coffee.
  1. Bicarbonates: Carbonate in water acts as a buffer for acidity and helps to neutralise the natural acidity found in coffee. This means it keeps the pH stable and can produce a more balanced flavour.

Today we’re not going to go too crazy with the science jargon. To describe the levels of Minerals and Bicarbonates in our coffee, we use the simpler terms, hard and soft.

Hard means that the water has a lot of minerals and bicarbonates. 
Soft means that the water has less minerals and bicarbonates and is the more favourable option for brewing coffee.

Have a look at the picture below:

Source: Barista Institute 

The water from your tap is generally going to be on the hard side, but to get great coffee at home, you need it on the softer side.

Without having to go too far out of your way, one of the easiest options for a hard water test is by using a clear, clean bottle with a cap, pure liquid soap and water right from your tap.
 Start by filling the bottle to one third full, add a few drops of pure liquid soap and shake vigorously for a few seconds. 
If there is a distinct lack of fluffy bubbles and the water appears cloudy and/or milky, then your water is hard.
 Soft water would have copious bubbles, and the resting water at the bottom of the bottle would be clear. 
Keep in mind that because most soaps are formulated with detergents, they lather regardless of your water type. For the best results, use a basic soap that’s free of dyes, perfumes and detergents.

Once you know what sort of water is coming out of your tap, then you can adjust to better suit your coffee brewing needs. There are a few ways to do this: 

  1. Use pre-filtration on your tap. There are plenty of accessories you can buy to attach to your kitchen tap which catches large particles on their way out.
  2. Try an activated carbon filter, such as a filter jug
  3. Fine filtration after the water has been treated is also an option to remove any fine particles from the water.

If you are a Melbourne local like us, then have a look at the guide below to see what exactly is in our water! We can certainly recommend checking on your local government’s website also to see their latest water report, to give you some insight.


So, there you have it: water is one of the most important ingredients of the coffee we drink and is an important factor to consider when wanting to brew the perfect cup of coffee at home! Who knew that transparent liquid had so much going on inside?! Let us know in the comments below if you have any questions. 

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