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Coffee Brewing Control Chart

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Coffee Brewing Control Chart

Sources: The Coffee Brewing Handbook by Rob Lingle (SCA, 2011)

The Coffee Brewing Control Chart (CBCC) was developed by the Coffee Brewing Institute (CBI) and Coffee Brewing Center (CBC) between 1952 and 1975. It remains the standard tool of the specialty coffee industry for objectively evaluating brew quality. The chart was confirmed by the Nordic Coffee Brewing Center and adopted by the SCAA. (source: SCA Coffee Brewing Handbook)

The Three Variables

The chart plots the relationship between three interdependent variables:

1. Strength (Solubles Concentration)

The percentage of coffee flavouring material dissolved in the final beverage.

  • Expressed as % TDS (Total Dissolved Solids)
  • A typical coffee beverage: ~1.2% coffee flavouring material + 98.8% water
  • Weak (below 1.15% TDS): flavour components don’t reach the taste threshold of the average person
  • Ideal range: 1.15–1.35% TDS (US/CBC standard); 1.30–1.55% TDS (Nordic/NCC standard)
  • Strong (above 1.35% TDS): components present at too intense a concentration

Strength is measured using a conductivity meter (TDS meter), a coffee hydrometer, or the oven-dehydration method. Modern TDS meters give a reading within seconds. 1,000 ppm = 1.0% solubles concentration; 1,250 ppm = 1.25%. (source: SCA Coffee Brewing Handbook)

2. Extraction (Solubles Yield)

The percentage of available flavouring material removed from the coffee grounds during brewing.

  • Approximately 28% of roasted bean mass will dissolve in water under normal brewing conditions; the remaining 72% is cellulose fibre.
  • Under-developed (below 18%): grassy, peanut-like tastes
  • Ideal range: 18–22% (confirmed by both CBC and Nordic Brewing Center)
  • Over-extracted (above 22%): astringent, bitter tastes

Different solubles yield values produce different flavour mixtures because each compound dissolves at a different rate. See Extraction.

3. Brewing Formula (Coffee-to-Water Ratio)

The ratio of ground coffee weight to brewing water volume.

Expressed as:

  • Grams per liter (metric; European standard)
  • Grams per 6 fl oz cup (single-cup brewers)
  • Ounces per 64 fl oz (half-gallon commercial brewers)
  • Gallons per pound (urn brewers)

The brewing formula determines the range of possible strength-extraction combinations. If two of the three variables are known, the third can be calculated.

The Ideal Zone

The CBCC identifies an “Optimum Balance” zone in the centre of the chart where strength and extraction are simultaneously within their preferred ranges. Three key principles define this zone, confirmed by both CBC and Nordic research:

  1. Extraction must be narrow: 18–22% is the only range where the most desirable combination of flavouring compounds is extracted.
  2. Strength has a broader acceptable range: 1.15–1.35% TDS is optimal; outside this range the flavour is either imperceptible or overwhelming.
  3. Only specific brewing formulas can achieve the ideal balance simultaneously:
    • Single-cup brewers: 9–11g per 6 fl oz (6.25–7.75g per 125ml European cup)
    • Metric brewers: 50–60g per liter (Nordic standard: 60–70g/liter)
    • Half-gallon brewers: 3.25–4.25 oz per 64 fl oz
    • Urn brewers: 2.0–2.5 gallons per pound

Using too much coffee and achieving preferred extraction produces a too-strong brew. Using too little coffee and achieving preferred extraction produces a too-weak, over-extracted, bitter brew. (source: SCA Coffee Brewing Handbook)

How to Use the Chart

  1. Measure brew strength with a TDS meter. Locate that value on the vertical axis.
  2. Locate the diagonal line representing the brewing formula (coffee:water ratio) used.
  3. Find the intersection of the horizontal strength line and the diagonal formula line.
  4. Drop a vertical line to the bottom axis to read the extraction percentage.
  5. If the intersection falls in the Optimum Balance zone, the brew is ideal. If not, identify which variable to adjust.

Diagnostic examples:

  • Result in “Strong, Under-Developed” zone → reduce coffee dose or coarsen the grind
  • Result in “Weak, Over-Extracted” zone → increase coffee dose or coarsen the grind
  • Result in “Weak, Under-Developed” zone → use more coffee; fine up the grind

Objective and Subjective Measurement

The chart measures taste (dissolved solubles) objectively, not aroma. Aroma compounds are volatile gases that extract almost immediately when grounds contact hot water — they contribute to the perception of flavour but not to the TDS reading.

Body is created by insoluble materials (principally oils and fine bean fibre) that form brew colloids. The filter type controls how many colloids pass into the brew. Brew colloids trap soluble flavouring materials and release them time-delayed on the palate. (source: SCA Coffee Brewing Handbook)

Relevance to Kaiserblick

The CBCC is the quality measurement framework used by Kaiserblick’s target customers — specialty roasters and coffee shops in Germany, France, Switzerland, and the Netherlands. Familiarity with the chart and the ability to help customers dial in their brew is a value-added service Kaiserblick can provide as part of its export offering. See Green Coffee Trading.

The chart explicitly notes: “This test does not indicate blend quality.” It measures brew performance given the coffee used — the coffee’s intrinsic quality (terroir, variety, processing) is a separate dimension.

Graph View

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