Section · brewing variables
Brewing variables: grind, water and extraction
Reference pages on the variables you control when brewing: grind size, water temperature and chemistry, the bloom, and how strength and extraction are measured. Each page explains one variable and links the standards and studies behind its figures.
ReferenceGrind size chartGrind by brew method, plus how contact time and grind size trade off.ReferenceWater temperature & chemistryThe 200°F ± 5° target, what the UC Davis research found, altitude, hardness and alkalinity.ReferenceDIY coffee water recipesDistilled water plus food-grade Epsom salt and baking soda: SCA hardness and alkalinity targets, published recipes in grams, and the ppm-as-CaCO₃ math.ExplainerCoffee bloom explainedWhy fresh coffee bubbles: CO₂ degassing by roast level and days since roast (ZHAW data), what bloom tests show, and a 2–3× water, 30–45 s method.ReferenceBrewing control chart explainedLockhart’s 1957 TDS-vs-extraction chart, its nine zones, and the new UC Davis sensory and consumer chart.ReferenceCoffee TDS + refractometersWhat a 1.3% reading means in grams and ppm, how a coffee refractometer reads a drop, published accuracy specs, a reading routine and a TDS calculator.