In coffee circles, there is a long going debate on whether your machine will work on hard water or not. While the short answer is yes, the long answer might make you want to think twice about it. I’m going to try to explain it as simple as I can how the water and coffee react, what is hard water, and what does this mean for your machine. Also, what can you do to negate the effects of hard water on your machine and your coffee.
First of all, every barista and coffee enthusiast knows that the water quality will significantly determine the quality of your brew and also the lifespan of your machine. Let’s think of it this way, roasted beans have an essential compound in them like lactic acid, eugenol and even citric acid. Like I said these are essential compounds, and these are what gives your beans their distinct flavors and aromas, and the percentage of each will depend on the origin.
However, tap water is also pretty complex and it has some compounds as well besides the normal Hydrogen and Oxygen, such as magnesium and calcium ions that may not be recognizable when drunk as water, but when brewing coffee with them you will notice that it impacts the taste of the brew significantly. Some of these compounds are even stickier such as Magnesium, and it will have a strong impact on your coffee, bicarbonate has also a very strong taste which gives the final brew a bitter flavor, which is really unpleasant and most baristas dread those circumstances.
What is hard water exactly? Well, to be exact all-natural water that is present in our taps contains some minerals and ions which may make it hard, unless it is distilled or boiled beforehand. Water picks up magnesium and calcium ions while flowing or sitting in rocks, rivers, wells or any reservoir. Some barista’s try to negate this by using distilled water only, however, this, as well as a negative effect on your coffee making the final brew, have a flat taste. So this only leaves us with two options either finding a water source with a light amount of minerals or using mineral water, both of which aren’t practical and not cost-effective.
How does hard water affect your machine? The water goes through the boiler and pipes of your machine and when it is heated it creates limescale, which in turn will slow the whole process and decrease the efficiency of the process, besides the taste aspect. Limescale can be removed with descaling of your machine, and while all machines develop limescale, those operating with hard water will need to be descaled more frequently.
There are three realistic ways of negating limescale, mineral build-up, and degradation of your coffee and those are using one of the best coffee makers for hard water, using a filter for your machine and descaling it regularly.