If magnesium is the variable you care about, it can be tempting to think that any magnesium salt should produce the same result.
But that's not how mineral formulation works.
Magnesium chloride and magnesium sulfate both provide magnesium.
They do not produce the same water.
Magnesium chloride
MgCl₂ dissociates approximately into:
Mg²⁺ + 2Cl⁻
So adding magnesium chloride increases both magnesium and chloride.
Magnesium sulfate
MgSO₄ provides:
Mg²⁺ + SO₄²⁻
Now the accompanying ion is sulfate instead of chloride.
The magnesium concentration may be matched.
The complete ionic composition cannot be.
Why this matters
If you compare:
Water A = magnesium from MgCl₂
Water B = magnesium from MgSO₄
and both contain the same magnesium concentration,
you have not created two waters that differ only in "magnesium."
You have created waters with different counter-ions.
That is precisely what makes the comparison interesting.
The counter-ion is part of the water
Chloride and sulfate have different chemical properties.
They can influence the overall ionic environment.
Sensory research has also associated different ions with different sensory directions.
But these associations should be treated carefully.
They are not universal flavour laws.
A better experiment
Prepare two waters with:
same magnesium
same alkalinity
similar overall mineralisation where practical
but different magnesium salts.
Then compare them.
The question becomes:
"What happens when the magnesium source changes?"
That is much more scientifically useful than saying:
"Magnesium tastes like X."
Why TDS can be misleading here
The two waters may produce different TDS readings.
Even if the magnesium concentration is identical.
That's because the accompanying ions contribute to conductivity and dissolved material.
So a TDS difference does not necessarily mean the magnesium changed.
This is why formulation is difficult
When you add a salt, you rarely add one ion.
You add an ionic pair or combination.
That means mineral formulation is a balancing exercise.
Changing one target can move several other variables.
Practical implications
If you're designing a magnesium-forward water, you should record:
the magnesium target
the salt source
the counter-ion
and the resulting composition.
This makes the water reproducible.
The Water Artist approach
We don't describe water simply as:
"10 ppm magnesium."
We want to know:
10 ppm magnesium from what?
That question is surprisingly important.
The experiment
If you have access to both magnesium chloride and magnesium sulfate, prepare matched magnesium waters.
Brew the same coffee.
Use the same recipe.
Taste blind.
Look for differences in:
aroma
acidity
sweetness
body
finish
and balance.
Then repeat with another coffee.
Now you have an experiment worth learning from.
The Water Artist
Same magnesium.
Different salt.
Different water.
And potentially a different expression.
Water is the canvas.
You're the artist.