tags: [] - coffee/brewing - coffee/brewing/water aliases: - TDS coffee flavour - Water minerals and taste - Dissolved solids taste coffee

TDS and Taste¶

Tags: #coffee/brewing #coffee/brewing/water Aliases: TDS coffee flavour, Water minerals and taste, Dissolved solids taste coffee Related: Water in Coffee MOC | Total Dissolved Solids | Optimal TDS Range | TDS Measurement | Mineral Taste Thresholds Status: ✅ Complete

Overview¶

The total dissolved solids (TDS) concentration of brewing water influences cup flavour through two mechanisms: the overall mineral load effects extraction dynamics and the chemical interactions between dissolved ions and coffee compounds, while the specific ions dissolved contribute their own flavour characteristics at sufficient concentration. TDS cannot be assessed as a single number in isolation — two waters at identical TDS can produce dramatically different cups depending on which minerals are dissolved. The relationship between source water TDS and brewed coffee TDS (beverage strength) is also distinct and should not be conflated.

Two Types of Taste Effect¶

Effect on Extraction¶

Source water TDS influences how efficiently coffee compounds dissolve during brewing:

Very low TDS: High concentration gradient between water (low solutes) and coffee solution (high solutes) drives aggressive extraction; can produce sharp, harsh, or over-extracted character
SCA range (75–250 mg/L): Balanced extraction dynamics; mineral ions facilitate compound solubility and interaction; full flavour development
Very high TDS (>300 mg/L): Reduced concentration gradient; extraction slows; cups may be under-extracted or lacking clarity; the water already contains substantial mineral character that competes with coffee flavour

Direct Ion Flavour Contribution¶

At their respective threshold concentrations, individual dissolved ions contribute perceptible flavour character:

Ion	Typical threshold	Flavour at threshold	Common range in water
HCO₃⁻ (bicarbonate)	~50 mg/L	Flat, bitter, chalky	10–500+ mg/L
Ca²⁺ (calcium)	~200 mg/L	Slightly mineral, chalky	10–200 mg/L
Mg²⁺ (magnesium)	~50–100 mg/L	Slightly bitter	5–50 mg/L
Na⁺ (sodium)	~150–200 mg/L	Salty	5–200 mg/L
Cl⁻ (chloride)	~200 mg/L	Salty, metallic at high conc.	10–200 mg/L
SO₄²⁻ (sulfate)	~250 mg/L	Dry, bitter, mineralised	10–300 mg/L
K⁺ (potassium)	~300 mg/L	Bitter	2–20 mg/L (typical tap)

In well-managed coffee water (SCA targets), ions should be at concentrations that support extraction without producing perceptible direct flavour contribution. The exception is bicarbonate, which is flavour-active at concentrations routinely found in municipal water.

Mineral Taste Thresholds in Coffee Context¶

Taste thresholds for water minerals are higher than their extraction-modifying thresholds: - Water with 100 mg/L calcium does not taste perceptibly of calcium, but the calcium is still modifying extraction - Bicarbonate is the exception: it is flavour-active at concentrations commonly found in tap water, which is why high alkalinity is so damaging to coffee quality

TDS Water vs. TDS Coffee (Beverage Strength)¶

The coffee industry uses "TDS" to refer to two different measurements: - Water TDS (source water): Mineral content of brewing water, in mg/L; SCA target 150 mg/L - Beverage TDS (brewed coffee): Dissolved coffee solubles in the finished cup, measured by refractometer in Brix, converted to % TDS; SCA target 1.15–1.45% (filter coffee)

Confusingly, both are called TDS. The beverage TDS is a measure of brew strength (how much coffee was dissolved), entirely different from the water TDS (how much mineral content the source water contains). See Total Dissolved Solids.

Key Facts¶

Source water TDS influences extraction dynamics and contributes direct ion flavour at threshold concentrations
Very low TDS (<50 mg/L): aggressive, thin extraction; very high TDS (>300 mg/L): slow, mineral-dominated extraction
SCA target range (75–250 mg/L, target 150 mg/L) supports balanced extraction without direct mineral flavour interference
Bicarbonate is the key exception — flavour-active at commonly encountered concentrations; alkalinity is the primary taste concern, not total TDS
Water TDS and beverage TDS (brew strength) are distinct measurements using the same abbreviation

References¶

Changelog¶

Date	Change
2026-04-28	Note created

This article is part of All-About-Coffee.com - The comprehensive coffee knowledgebase.