Cup & RatioStart here
Understand extraction, water and grind without losing sight of the cup. Use the calculators, keep a simple brew record and change one variable at a time.
A calculator can make the arithmetic clear, but it cannot taste the coffee or see water channel through a puck. Our guides connect useful measurements to their assumptions and practical limits. Recipe examples are starting points for comparison, not promises that every coffee or espresso machine should use the same settings.
1. Understand your numbers
Keep coffee dose, beverage mass and dissolved solids in the right units. For a simple beverage-based calculation, 250 g of coffee at 1.20% TDS contains 3 g of dissolved coffee. Dividing by a 15 g dry dose gives 20% beverage-based extraction yield. Writing out the units helps avoid confusing 1.20 with the decimal fraction 0.012.
2. Adjust strength
See how dilution changes concentration after extraction. If 200 g of coffee measures 1.50% TDS, it contains an estimated 3 g of dissolved solids. Adding 50 g of plain water gives 250 g at approximately 1.20% TDS. The amount of coffee extracted has not increased; the same dissolved material is distributed through more liquid.
3. Understand your water
Separate hardness, alkalinity and a conductivity-based TDS reading. A water report can list calcium, magnesium, hardness and alkalinity in different forms. Values reported as calcium carbonate equivalents are a common comparison basis, but they are not the same as the mass of each dissolved mineral. Read the units before entering a calculator.
Use a simple decision record
Write down the item or recipe, what you observed, the conditions and the single change you want to try. Include units where a measurement matters. The aim is a repeatable comparison, not a complicated record that you never use.
If a result is unexpected, return to the starting assumptions before increasing temperature, concentration or treatment time. A different material, product formulation or instrument can change what advice applies.