Espresso Brew Ratio:1:2.3 Extraction Time: 27-32 seconds. This means that for every gram of ground coffee dosed into the porta-filter there is 2.3 grams of coffee extracted. If using and dosing with an 18g porta-filter you can extract approximately 42-grams of liquid (coffee). Still stuck? Check out this link to learn more about brew ratios -click here.