What is the ideal TDS for filter coffee?

The ideal TDS for filter coffee (V60, Chemex, batch brew, AeroPress, etc.) falls between 1.15% and 1.45% by mass, according to the SCA Brewing Control Chart (BCC). The central value of 1.30% is often cited as the reference target. Below 1.15% the cup is too weak; above 1.45% it is too strong and may taste bitter.

Filter coffee TDS is a fundamental parameter formalised by the SCA in its Brewing Control Chart (BCC) since the 1960s, through the work of Dr Ernest Lockhart for the Coffee Brewing Institute. The BCC is a two-axis graph relating TDS (concentration) to extraction yield (the percentage of solubles extracted from the coffee mass), defining an optimal quality zone — sometimes called 'the ideal brewing box'.

The SCA ideal zone for filter is: TDS between 1.15% and 1.45%, with extraction yield between 18% and 22%. These two parameters are linked by a dilution formula but are not equivalent: a coffee can have the right TDS but the wrong yield (for example, using more water but over-extracting — giving good TDS with a bitter profile, a common trap).

In practice, sensory perception evolves across this range. Between 1.15 and 1.25%, the cup is light, delicate, suited to highly aromatic coffees or comparative tastings. Between 1.25 and 1.35%, it is versatile — the zone of most competition barista recipes and professional batch brewers. Between 1.35 and 1.45%, it becomes richer, suited to full-bodied coffees or those who like 'strong' coffee without over-extraction.

Variables that raise TDS: higher coffee-to-water ratio (e.g. 70 g/L → 90 g/L), finer grind, higher water temperature, more agitation, longer bloom. Variables that lower it: lower ratio, coarser grind, lower temperature, less agitation, bypass of a portion of cold water at end of brew.

Professional baristas measure TDS with a coffee refractometer after allowing the sample to cool to room temperature (the reading is temperature-sensitive). Some also use palate: coffee at 1.15% has a translucent lightness comparable to a mild white tea; at 1.45%, an intensity close to continental hotel coffee. The ideal sits between these extremes, depending on the coffee, the method and personal preferences.

Filter coffee TDS: SCA zones and perception