Clarifying Terms Relating to Brew-Ratio and Extraction
This term brew-ratio can cause confusion in the way it’s expressed. Most baristas use ‘grams per litre’ for filter coffee and ‘Espresso Brew Formula’ (EBF) for espresso, but this is far from a rule.
Grams per Litre: The traditional way this term is applied is grams per litre where the ratio refers to your total brew water amount. For example, a batch brewed filter coffee machine dispensing 1L of water using 60g of coffee, would be called 60g/L.
Mills per gram: People often break this down to a ratio where they establish how much water you add for every single gram of coffee, so for the example of 60g/L the ratio would be reduced to 16.6667:1 (1000ml divided by 60g).
Note: This term when applied to espresso-based drinks gets confusing as baristas often use the mills per gram expression — but they use beverage weight instead of brew water. This is partly because it’s almost impossible to find how much water was actually used to make the espresso. So 18g of coffee producing a 36g double espresso would be expressed as a 1:2 ratio.
Brew-Formula: When VST released their brewing software, it helped proliferate the term Espresso Brew Formula (EBF). Instead of using the term ratio, they started expressing the relationship between the dose of coffee and the beverage weight as a percentage the dose to the beverage weight. So an 18g dose and a 36g beverage weight would be expressed as a 50% EBF (18g is 50% of 36g).
Liquid Retained Ratios (LRR): When you brew coffee, not all the water you use manages to leave the grinds. When brewing filter coffee the coffee bed will usually hold on to a little over 2ml of water per gram of coffee. With espresso, the spent puck will absorb a little over 1ml of water per gram of coffee.