Water is often underestimated in coffee discussions, even though it makes up almost the entire beverage and directly shapes the final taste. In specialty coffee, water isn’t a technical detail — it’s a core ingredient. The right water can highlight a coffee’s best qualities; the wrong one can mute them completely.

Minerals in water interact with the compounds extracted from coffee and influence:

• acidity (how bright or flat the coffee tastes)
• sweetness (how round and pleasant the flavor feels)
• clarity of aromas
• body and texture

This is why two identical coffees can taste completely different when brewed with different waters.

The Calcium-Magnesium balance: the foundation of good brewing water

In coffee, it’s not the individual mineral values that matter most, but the balance between them.

Calcium (Ca)

• contributes to body and structure
• supports a round, full mouthfeel

Magnesium (Mg)

• enhances sweetness
• highlights positive flavor notes
• improves extraction efficiency

A Ca:Mg ratio of 2:1 or 3:1 works well in most cases, though it’s not a strict rule.

Baristas adjust water depending on the coffee profile:

• African, floral coffees → more magnesium for clarity and sweetness
• South American, chocolatey coffees → more calcium for body and balance

If water contains no chlorides at all, coffee may taste less sweet. Chlorides help round out the flavor when balanced with other minerals.

Bicarbonate (HCO₃⁻) controls water alkalinity and shapes how acidity is perceived.

In small amounts, bicarbonate:

• stabilizes acidity
• provides balance
• prevents sharp, harsh flavors

In high amounts (common in many regions):

• neutralizes natural acidity
• mutes aromas
• makes coffee taste flat and heavy
• can increase bitterness

Common myths about water and coffee

“Bottled still water is perfect for coffee.”

Not necessarily. Most bottled waters have unsuitable mineral content.
For example, compared to tap water in Cluj, almost all bottled waters are harder.

What works for us:
A mix of 40% Bucovina + 60% distilled water, giving us ~80 PPM and a balanced mineral profile.

“Filtered water is enough.”

Filtration removes impurities but doesn’t always correct mineral balance.
Sometimes filtered water becomes too soft → weak extraction, flat taste.

“Good beans taste good no matter the water.”

Even excellent coffee can taste bitter, dull, or unbalanced with the wrong water.

Industry debates

Should coffee shops use standardized water?

Some say yes, for consistency.
Others believe adapting to local water is a key skill.

Is there such a thing as ‘ideal water’?

SCA standards are guidelines, not absolutes.
Some coffees shine with harder water, others with softer water.

Is special brewing water worth it at home?

It depends on how much you enjoy experimenting.
Some people use mineral packets; others prefer simple solutions.

So, 

Water isn’t a technical footnote — it’s a strategic ingredient.
Calcium, magnesium, bicarbonate, and chlorides directly shape the final cup.

Experiment: change the water, keep the same coffee, and taste the difference. It’s the fastest way to understand how flavors work and how balance is created.