What is an ideal extraction yield?

The ideal extraction yield (EY) sits between 18 and 22 %, as set by the SCA Golden Cup standard: it is the percentage of the dry grind that actually ends up dissolved in the cup. Below it the coffee tastes sour; above it, bitter and astringent. The 20-21 % band is the preferred sweet spot of specialty baristas.

EY is calculated, not measured. The formula: EY (%) = (TDS × beverage mass) / dry coffee mass. A simple V60 example: 18 g coffee, 300 g beverage, TDS 1.38 % → EY = (1.38 × 300) / 18 = 23 %. The classic shortcut is the SCA Brewing Control Chart; digital equivalents include the VST Coffee Tools app (iOS/Android) and Matt Perger's Barista Hustle brew calculator.

The 18-22 % window is not arbitrary. It comes from Ernest Earl Lockhart's MIT work in the 1950s, adopted by the Coffee Brewing Institute, then ratified by the SCAA in 1995 and the SCA in 2017. Below 18 %, acids dominate (citric, malic) before sugars and Maillard compounds have time to dissolve: salty-sour taste, hollow finish. Above 22 %, heavier phenolic compounds and partly soluble tannins start to surface: dry bitterness, ashy sensation, astringency.

The exact target depends on sensory intent. Scott Rao has argued since his 'Coffee Brewing Handbook' (2008) for high EY around 21-22 % to maximise sweetness and complexity in a light Scandinavian roast. James Hoffmann, in 'The World Atlas of Coffee' (2014) and on his YouTube channel, more often targets 19-20 % for a medium European roast. In espresso, VST long recommended 20-21 %; British champion and 'Coffee Dictionary' author Maxwell Colonna-Dashwood notes that competition baristas often drop to 19 % on anaerobic naturals to protect the fruit.

In Belgium, specialty roasters in Brussels and Ghent now routinely publish recipes with explicit EY targets: 20 % on a washed Ethiopian, 21-22 % on a Costa Rican honey, 19 % on a Panamanian natural. Feedback from baristas trained at the Antwerp Coffee Academy or Brussels Coffee Project converges on one point: with the hard tap water of Flemish Brabant (25-30 °f), EY tends to cap lower than in Scandinavia, which explains the growing use of remineralised water such as Third Wave Water or Lotus cartridges.

EY targets by coffee style