What is the brew chart or Golden Cup standard?

The Brewing Control Chart — the SCA's 'Golden Cup' — is a two-axis diagram: EY on the x-axis (14 to 26 %) and TDS on the y-axis (0.8 to 1.8 %). At its centre, a rectangular sweet spot (EY 18-22 % / TDS 1.15-1.35 %) defines a balanced filter coffee per the SCA standard.

The Brewing Control Chart was designed in the 1950s by Ernest Earl Lockhart for the Coffee Brewing Institute, precursor to the SCAA and the SCA. The chart crosses two variables: concentration (TDS) and yield (EY). The ideal rectangle sits inside four labelled corners: high TDS + low EY = 'strong underdeveloped' (strong but sour); low TDS + high EY = 'weak bitter'; high TDS + high EY = 'strong bitter' (over-concentrated, over-extracted); low TDS + low EY = 'weak underdeveloped' (thin and sour).

The SCA ratified the 18-22 % EY / 1.15-1.35 % TDS window in 1995 for filter coffee, reaffirmed in 2017 at the SCAA-SCAE merger. Matt Perger modernised the visualisation in 2015 with the Barista Hustle 'coffee compass': same idea, wider axes (14-26 % EY, 0.8-2 % TDS) to cover espresso, French press and cold brew, with a moving target by method. The compass made it visual that espresso at 9 % TDS / 20 % EY is balanced, whereas a V60 at 9 % TDS would be undrinkable — the target shifts with the method.

In practice, the chart works like a diagnostic compass. Brew the coffee, read TDS (VST or Atago refractometer), calculate EY, plot the point. If it lands bottom-left, you have an under-extracted, over-diluted cup: tighten grind, raise dose or time. If top-right, an over-extracted, over-concentrated cup: open grind, dilute. Scott Rao stresses in 'The Professional Barista's Handbook' how this feedback loop pulls quality evaluation out of pure subjectivity.

In Belgium, the chart is taught in the opening module of specialty programmes (Antwerp Coffee Academy, Brussels Coffee Project, SCA Foundation and Intermediate Brewing). It hangs in most Brussels and Ghent roastery labs, printed A3 with a paper grid for daily trials. At the Belgian Barista Championship, being able to plot an espresso on a coffee compass is an implicit expectation of the sensory judges.

SCA brew chart zones and interpretation

Reading the compass: where does your coffee actually plot?

The Brewing Control Chart originated in research commissioned by the Pan-American Coffee Bureau in the 1950s, eventually codified by MIT-trained chemist Ernest Lockhart and later adopted by the NCA and SCAA. What makes it enduringly useful is its two-axis clarity: extraction yield on the horizontal axis, brew strength (TDS) on the vertical, with a diagonal 'ideal zone' that defines the relationship between the two. A coffee can be correctly extracted but too weak (high EY, low TDS — typical of a 1:20 ratio brew), or correctly concentrated but under-extracted (low EY, high TDS — a short, intense espresso that hasn't dissolved enough compounds to taste complete). The chart makes these trade-offs visible.

Matt Perger's 'Coffee Compass' extended the chart into a navigational tool: eight directional cells surrounding the ideal centre zone, each labelled with a corrective action. North means too strong (dilute or reduce dose). Northeast means too strong and over-extracted (cool the water or open grind). This compass framing turned a descriptive chart into a decision engine — given where your shot or filter brew lands, the compass tells you exactly which knob to turn next. Perger published it freely in 2015 and it has since been translated into over a dozen languages, printed on espresso bar walls from Melbourne to Montreal.

Going deeper

Home brewers who invest in an inexpensive refractometer — the Atago PAL-Coffee model costs around €100–130 — can begin plotting their own brews within an afternoon. The protocol is simple: brew normally, take a 5 mL sample, cool it to room temperature, apply to the prism, read TDS percentage. Plug that value and your brew ratio into the formula (EY = TDS × brew weight / dry coffee weight × 100) and locate the point on the chart. Over three or four brews, a pattern emerges. Most beginners discover they are consistently under-extracting — their cups feel sour not because the beans are bad, but because water contact time, temperature or grind isn't sufficient to reach the 18–22% target zone. The chart, in that sense, is one of the most honest pieces of feedback available to a home brewer.