Pour-over ratios, explained properly

A brew ratio is just coffee weight against water weight. Written as 1:16, it means one gram of coffee for every sixteen grams of water - 30g of coffee into 480g of water, and so on. That is the entire concept.

Why 1:16 is the usual starting point

It sits in the middle of the range where a medium roast tastes balanced without being either syrupy or watery. It is a default, not a law, and it is the number to return to whenever you have changed too many things and lost the thread.

Moving the ratio on purpose

• 1:14 - heavier body, lower clarity. Good for darker roasts and for drinking with milk.
• 1:16 - the balanced middle. Start here with anything new.
• 1:18 - light, tea-like, more aromatic. Suits delicate washed coffees and light roasts.

What a ratio cannot fix is grind size. If the brew runs through in ninety seconds, adding coffee will not save it; the water is still leaving before it has taken anything with it. Fix the drawdown time first, then adjust the ratio for body.

A worked example

For a two-cup V60: 22g of coffee, 350g of water at 94C, poured in four additions about 45 seconds apart, finishing the drawdown around three minutes. If it finishes much earlier, go finer; much later, coarser.