Coffee numbers, worked out
Enter what you know and get an exact answer. Every page shows its working. Anything still under debate is footnoted so you can see where the disagreement is.
Water recipe
Target alkalinity and hardness → grams of baking soda, Epsom salt and gypsum per liter, with the resulting ion ppm and TDS.
Extraction yield
Refractometer TDS, dose and beverage weight → extraction %, checked against the 18–22% window.
Ratio scaler
Scale 1:15–1:17 pourover, 1:2 espresso or your own ratio, from dose or from output.
Strength adjuster
Current TDS and amount → water (or stronger coffee) to add to hit a target.
Caffeine estimator
Dose, coffee and method → estimated caffeine, shown as a range.