Cafe Hacks — Water Filtration For Coffee

Is Your Water Ruining Your Coffee?

Water in the coffee world is often overlooked and taken for granted, but its impact on how your coffee tastes shouldn’t be understated. Especially considering that the majority of your coffee is made up of water and the composition of water will influence extraction. You can have the world’s best coffee but if you are pulling espresso shots with, or adding water that is not going to bring out the best out of your coffee then you are setting yourself up for disappointment. The good news is that it is something that is easy to fix, will improve your coffee and save you money and heartache in the long run.

Water filtration for coffee

Breaking Bad Water

Water is made up of minerals. Some good for extraction, some bad. The mineral makeup of the water used affects its taste and will impact your coffee. For example, magnesium brings out the acidity in the cup fruity and calcium helps bring out the body. But water which is oversaturated with minerals will not extract coffee as well as it could, as there will be less ‘space’ for coffee extraction to take place and bring out the taste or flavours that we should be looking for.

With subpar water, you won’t only be making bad coffee, you will also damage your coffee equipment over time and degrade its performance. Soft water has a lack of calcium and magnesium ions so can leave your coffee tasting flat and empty. Hard water, on the other hand, can leave that lovely residue we know as limescale as it evaporates. Limescale is that chalky deposit found in kettles, hot-water boilers, and taps (especially if you live in London) and the build-up of limescale is not only gross but it can have a serious impact on how well your espresso machine is working. Limescale could make it hard for the espresso machine’s boiler to heat water efficiently, and limescale build-up in pipes can restrict water flow and therefore pressure. Just in case you don’t care about having to potentially pay for expensive repairs or replace your espresso machine, your coffee won’t taste very nice either.

Is it All About Chemistry?

As you can probably tell, water is a very deep (sorry) subject, fortunately, the SCA has put together this handy table listing the different water characteristics that we should be aware of. The things to look out for here are the TDS, water hardness and pH levels.

TDS: Total Dissolved Solids (TDS) is measured with the aid of a refractometer. The acceptable range is 75 to 250 mg/L, with a recommended target of 150 mg/L.

Calcium Hardness: Calcium Hardness is measured with a titration kit. Acceptable range 1 - 5 grains per gallon (gpg) or 17 mg/L - 85 mg/L, with a recommended target of 4 grains or 68 mg/L

pH: pH indicates the level of acidity or basicity in water, and can be measured with a test kit. The acceptable range is 6.5 to 7.5, but you should be aiming for 7.0.

Water Filtration is Your Friend

The way to regulate the characteristics your water supply is through the use of a water filter system. There are quite a few options to choose from, but here are two solutions commonly used:

  • There’s the CTU softener which softens the water and reduces the number of minerals in the water. The plus side is that they are an affordable and simple solution for reducing limescale and improving taste somewhat. The downside is that they can only soften the water to a certain level. How much the water is softened is completely dependant on the water coming in from the mains. 
  • Then you have RO (reverse osmosis). This is a much more elaborate filtration system. With this, you are able to control the mineral content (parts per million - PPM), for ideal extraction. The downside is that they are expensive and can be wasteful. Although you can control PPM and water hardness with reverse osmosis, you can't control the ratio/quantities of magnesium, calcium and bicarbonate in the water. So although a step in the right direction, it is by no means the absolute solution.

Do These Things to Prolong the Life of your Coffee Equipment

To avoid machine breakdowns and bad coffee, we recommend regular maintenance:

  • Backflushing and thoroughly cleaning your espresso machine daily
  • Using a water filtration system that is suited for cafes and to your local water supply, and replace your filters as per the recommended manufacturer's guidelines
  • Testing your water (TDS, calcium hardness and pH) every month, or more often depending on volume
  • Yearly maintenance and a comprehensive health-check on your espresso machine

The solution is quite straightforward, if not a little TDS (tedious)... But hopefully, this journal entry will give you a better understanding of the importance of your water supply, what to look out for and how to keep your espresso machine in tip-top shape and pumping out delicious espressos.


If you think you might be having an issue with your water and you use Climpson’s coffee, please contact your account manager and we can arrange to test your water and help you to take the necessary steps to get it tasting perfect.

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