Coffee Brewing Control Chart Calculator
No refractometer? See where your brew ratio lands on the SCA Brewing Control Chart and roughly how strong it will taste.
Calculator
Ideal — Golden Cup
Balanced strength and extraction. A great target ratio — taste and adjust to your beans.
About this calculator
The SCA Brewing Control Chart is the famous map of a great cup: strength up one axis, extraction across the other, with a "Golden Cup" box in the middle. Most charts need a refractometer. This one does not — give it your dose and water and an assumed extraction, and it estimates your strength and plots where your recipe lands, so you can see whether your ratio is in the box before you even brew.
How to read your results
Two independent dials. Your brew ratio (dose vs water) sets the strength: tighter ratios brew up, wider ratios brew down. Grind, time and temperature set the extraction: finer/longer/hotter moves right. The Golden Cup box is 18–22% extraction × 1.15–1.35% TDS. The extraction here is an assumption — drag it to explore, and measure with a refractometer for the exact spot.
How it's calculated
Beverage in the cup ≈ water − about 2 g retained per gram of grounds. Strength (% TDS) = assumed extraction % × dose ÷ beverage — the inverse of the extraction-yield formula. The brew ratio is water ÷ dose. The Golden Cup bands (extraction 18–22%, strength 1.15–1.35% TDS) come from the SCA Brewing Control Chart.
Worked example
18 g of coffee, 324 g of water, assuming a typical 20% extraction.
That is a 1:18 ratio. At 20% extraction the strength works out to about 1.25% TDS (12.5 g/L) — right inside the Golden Cup box.
Frequently asked questions
Why do I have to assume an extraction?
Because without a refractometer you cannot measure it. Most well-made filter coffee lands around 18–22%, so that is a reasonable assumption. Slide it to see how much your perceived strength depends on it, then measure if you want the real number.
How is this different from the extraction-yield calculator?
That one takes a measured TDS reading and computes your real extraction. This one works backwards from your recipe with an assumed extraction — handy for planning a brew or choosing a ratio when you do not own a refractometer.
My cup is in the box but tastes off — why?
The chart is a guide, not a guarantee. Uneven extraction (channeling, an inconsistent grinder), water chemistry, roast and bean all shift flavour independent of the average numbers. Use the chart to pick a ratio, then dial by taste.
Sources
- podiumcoffeeclub.com/blogs/blog/sca-brewing-control-chart
- www.baristahustle.com/towards-a-common-coffee-control-chart
Reviewed by the YouCalc Team · Last reviewed
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