Why coffee ratios are measured by weight, not scoops or cups
A "scoop" of coffee varies enormously depending on grind size and roast — a coarse French press grind takes up more volume per gram than a fine espresso grind, so measuring by volume gives an inconsistent actual coffee-to-water ratio even when you use "the same scoop" every time. Weight removes that inconsistency entirely, which is why serious coffee brewing (and every major brewing guide) specifies ratios in grams. Water is close enough to 1g per mL that weighing water and measuring it by volume are effectively interchangeable for this purpose.
Choosing a ratio for your taste
Lower ratios like 1:15 use more coffee relative to water, producing a stronger, more concentrated cup — good for those who prefer bold coffee or take milk. Higher ratios like 1:17 or 1:18 use less coffee relative to water, giving a lighter, more delicate cup that lets subtle flavor notes come through more clearly — common in specialty pour-over brewing where highlighting the bean's specific flavor is the goal.
FAQ
Does the ratio change by brew method? Somewhat — French press often uses a slightly stronger ratio (1:15-1:17) than pour-over (1:16-1:18), since immersion brewing extracts differently than drip-through brewing.
Can I use a kitchen scale instead of a coffee scale? Yes — any scale precise enough to read in whole or half grams works fine for this purpose.