Ask a group of specialty coffee brewers what the best water for coffee is, and you will probably get several different answers.
Some will recommend distilled water with minerals added. Others will prefer a particular bottled water. Some will talk about TDS, while others will focus on hardness, alkalinity, calcium or magnesium.
So, which one is actually the best?
The honest answer is: there isn't one.
The best water depends on the coffee, the brewing method, and the expression you are trying to achieve.
Water is more than a background ingredient
Coffee is mostly water, but water is not simply a neutral carrier.
The dissolved minerals in brewing water can interact with compounds in coffee and influence the brewing environment. Research by Hendon, Colonna-Dashwood and Colonna-Dashwood helped establish the importance of dissolved cations in coffee-water chemistry.
That means changing the water can change the cup.
A coffee can become more expressive, more rounded, more delicate, or less defined depending on the water used.
This is why two brews using exactly the same coffee, grinder and recipe can still taste noticeably different when brewed with different water.
So what makes good coffee water?
There are several properties worth paying attention to.
Mineral composition
Calcium and magnesium are among the most discussed ions in coffee brewing water.
But mineral composition is broader than a single ion or a single TDS number.
Two waters can have similar overall mineral content while containing very different proportions of calcium, magnesium, sodium, bicarbonate and other ions.
Those differences can matter.
Alkalinity
Alkalinity is another important part of the picture.
Bicarbonate contributes to the water's buffering capacity, which affects how the acidity of coffee is expressed.
Too much buffering can make a coffee feel flatter or less vibrant.
Too little can leave some coffees tasting excessively sharp.
The goal isn't necessarily to maximise or minimise alkalinity.
It's about finding a balance that works with the coffee.
TDS
TDS is useful, but it shouldn't become the entire conversation.
A TDS meter gives you an estimate of the dissolved material present in water. It does not tell you exactly which minerals are present or how those minerals interact with coffee.
Two waters can have similar TDS readings while having very different mineral compositions.
And therefore, they can produce very different cups.
There is no universal perfect water
A washed Ethiopian Gesha may invite a different water approach from a naturally processed Brazilian coffee.
A light roasted coffee may behave differently again.
So instead of asking:
"What is the best water for coffee?"
we think the better question is:
"What water helps this coffee express itself best?"
That small change in perspective makes water much more interesting.
Water as a creative variable
This is where The Water Artist begins.
We don't believe the purpose of coffee water is to make every coffee taste the same.
We believe water can be used as another variable in brewing — alongside grind size, temperature, ratio and agitation.
The coffee brings its own character.
Water helps reveal how that character appears in the cup.
The best water is the water that fits the coffee
There is no universal recipe that makes every coffee better.
Instead, think of water as part of the brewing recipe.
Coffee + Water + Extraction = Expression
Change the water, and you may change the expression.
That is what makes coffee water worth exploring.
Not because there is one perfect mineral profile.
But because different coffees can reveal different things when given the right water.
The Water Artist
Water is the canvas.
You're the artist.