CremaTheory

Ratio scaler

A ratio is the one part of a recipe that still works when you change the batch size. Once you have one you like, you can brew one cup or a carafe from it. Filter and espresso people mean different things by the second number, though. For pourover it's the water you pour. For espresso it's the liquid in the cup. This page keeps track of which one you mean.

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How it's worked out

  1. Spent grounds hold some liquid back, usually around 2 g for every gram of coffee in filter brewing. Reported figures run from about 1.8 to 2.2 depending on grind and filter. So the cup-weight figure for pourover is an estimate. Weigh your cup once and adjust this number to match your setup. Espresso isn't converted because you weigh the shot directly.
  2. 1:15–1:17 is the common pourover range and 1:2 the common espresso starting point. They are conventions, not rules.