I live in a hard water area and when brewing English Tea I can definitely taste and see the difference when compared to where I'm from, which is a soft water area.

Does the hardness of the water matter when making coffee, too?

For instance, whether or not the taste is more or less intense depending on the hardness of the water. I haven't noticed but I would think it does affect the flavor.

I'd be interested in a scientific/objective view. As of now, I use bottled water in my kettle.

  • 1
    Some coffee shop owners felt the water mineral variability problem (soft vs hard etc) was important enough to tackle that they recently launched Third Wave Water a product that re-adds minerals to distilled water for a consistent brewing experience. I haven't used it yet myself but have heard good things from baristas in the know. Mar 12, 2017 at 5:20

2 Answers 2



That is to say it will definitely affect flavor, but how it affects the flavor is ultimately dependent upon the specific mineral compounds found in your hard water vs. other hard waters and soft water's lack of these compounds.

Here's the key: Some of the compounds in hard water are "sticky," glomming onto certain compounds in coffee when they meet (in your coffeemaker). The more eugenol the water hangs on to, for example, the woodsier the taste of your coffee will be.

Magnesium is particularly sticky, meaning water that's high in magnesium will make coffee with a stronger flavor (and higher levels of caffeine). Hard water can also have high levels of bicarbonate, though, which Hendon found could lead to more bitter flavors coming through. - A Chemist Has Uncovered A Secret To Brewing Delicious Coffee At Home Business Insider.

So depending on flavor preferences you might prefer your hard water at home but dislike it at work or simply prefer soft water altogether. Traditionally hard water is actually sought after for other beverage processes like beer brewing because of some of the abilities described above.

  • That's interesting I have noticed that since using bottled water in my kettle that my coffee tastes better but that could be psychological
    – EdChum
    Jan 27, 2015 at 21:05
  • @EdChum What is the mineral content of your bottled water? Is it from a natural spring source? Is it treated with anything? May 17, 2015 at 14:59
  • @PatrickSebastien my bottled water is the supermarket's own brand still water which is the cheapest in the UK, I did try a branded one which probably because it was more expensive actually left residue similar to my tap water
    – EdChum
    May 19, 2015 at 18:49
  • There are several news articles across the web that actually prove why places such as NY/Seattle have the best coffee - they have the "best" water; the hardness level is much lower than midwest/southern states. theatlantic.com/science/archive/2016/04/coffee-scientist/480015
    – Geo
    May 2, 2016 at 16:07

Just to provide more information to reaffirm @joshua's answer, there is an entire book that talks about this topic: Water For Coffee - Maxwell Colonna-Dashwood & Christopher H. Hendon with scientifical arguments.

On the other hand, La Marzocco's Reverse Osmosis System provides proper water for their espresso machines, another reason that makes clear that water is really a thing on coffee.

  • Omar, did you read this book? If yes, do you recommend it? If it is valuable you may want to mention it on this question where I'm trying to compile a list.
    – MTSan
    May 13, 2016 at 19:34
  • The link to that book is broken now.
    – Ukko
    Oct 31, 2019 at 20:16
  • 1
    @Ukko I just updated the link. Nov 22, 2019 at 15:37

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