Many espresso machines and fully automatic coffee makers have plug-in functions for water filter cartridges. But are the plug-in filter cartridges any good? We tested 5 models and summarized the results in a video about plug-in water filters from BWT, Brita, Jura, Lelit, and Sage.
The importance of water for coffee preparation
Water plays a central role in the preparation of coffee. This is no surprise, as every coffee drink consists of well over 90% water. Nevertheless, for a long time the focus was mainly on machine protection and less on the effects of water on taste. Conveniently, the water that tastes good in coffee is also the water that protects machines. We recommend the following water hardness levels.
Perfect water for filter coffee:
Total hardness: 2 – 3 °dH
Alkalinity: 1 – 2 °dH
Perfect water for espresso:
Total hardness: 3 – 6 °dH
Alkalinity: 2 – 4 °dH
In our detailed water article we have thoroughly covered the reasons and basics of water chemistry. We also provide tips there on which methods can be used to test water at home and what the limitations of filtration are. Another article is dedicated to filter water pods. We are currently working on a test of filter water jugs.
Water filter cartridge test results
The following summary of test results shows how the water filter cartridges perform. For the test, the filter cartridges were first prepared as recommended by the manufacturer. Then one liter of water was pumped through the filter and measured. This was followed by five more liters and another measurement, as well as five more liters and another measurement. Finally, 10 liters were pumped through the filter and measured again.
Measurements were taken using a drop set for hardness testing and a conductivity meter.
Results in German hardness = dH.
Special pump for measuring filter cartridges
Normally, the filter cartridges are installed in the water tanks of coffee machines. The water is pumped through the filter cartridge by the coffee machine and then heated. Measuring the already heated water would not have given us usable results, as heating causes a change in the water.
That's why we worked with an external pump where we could regulate the flow so that it matched the flow rate of the espresso machines.
Does the inlet water matter?
The tests were conducted with water having an inlet hardness of 13° total hardness German hardness and 11° dH alkalinity. The filter performance was also adequate for water hardness levels up to 25° German hardness. The filters generally filter down to approximately the target value. However, the durability of the filters is significantly reduced when harder water is used.
Are water filter cartridges recommended?
3 out of 5 filters delivered good results throughout the entire test. The filter performance is also better than, for example, with tabletop water filters. Just a small preview of the results from our tabletop water filter test.
The Jura Claris Filter shows its strength once several liters have run through the cartridge. It does good work overall and allows for good coffee while protecting the coffee machine.
The Brita Intenza also achieves good target values, especially from 5 liters onwards. Conclusion: good for coffee and machine, also quite strong for filter coffee because it tends toward the softer range.
The BWT Best Cup Water Filter remains somewhat too hard. It doesn't get going at the start, and even after some flow, the values barely reach the target range. Even though a good hardness window is briefly achieved after 6 liters of flow.
The Lelit MC747 is not a decalcifier but a desalter. It removes magnesium and calcium from the water but leaves the alkalinity. This protects the espresso machine but doesn't prepare the water well for brewing delicious coffee. The Lelit filter is not well suited for the preparation of sensorially high-quality coffee.
The Sage Filter gets going after approximately 11 liters have been flushed through and then brews water on the softer side that is good. This filter can be installed in espresso machines such as the Sage Barista Pro or Sage Barista Touch. The water values are also very well suited for brewing filter coffee.
If you want to learn more about the perfect water for coffee, you'll find all our articles on the subject here.
