What is Espresso Ratio
The term ratio refers to how much ground coffee you use, also known as the ‘dose’, to how much the weight of the coffee you make, known as the ‘yield’. For example, using an 18g dose, stopping the shot at 36g yield produces a dose:yield ratio of 1:2.
If you have 20g dose and 40g yield, the ratio is also 1:2 and the extraction will taste the same.
The role of water
Water is a powerful solvent. Because of its polarity and ability to form hydrogen bonds, water makes an excellent solvent, meaning it can dissolve many different molecules.
That is what you are doing when making coffee, dissolving flavor compounds out of the coffee grounds. The more solvent you use, the more compounds you extract.
When under extracted coffee is sour, you need to extract more, so you need to use more solvent water. And when over extracted coffee is bitter, you need to extract less by using less solvent water.
The importance of Ratio
Ratio is THE most important parameter to change when making coffee. In a golfing analogy ratio is like your big driver club, it is your most powerful tool. It would be like playing golf using only a putter if you never vary your ratio. That might be OK for the kids playing mini golf, but you want to be out there with the pros like Tiger Woods, using all your tools to their full abilities to make the best-tasting coffee possible, don’t you?
What espresso ratios are there?
The standard espresso ratios are:
1:4 Lungo Allongé
These are the rough names. The reality is ratio is a continuous scale, you might need a 2.7 for example.
Ratio Use Cases
Very dark roasts will taste less bitter and sweeter, with lower extraction ratios, which is what the Espresso Ristretto 1:1 ratio caters for.
Generally, I’m not a fan of the dark roast because it tends to burn off the fruit notes. But when faced with a dark roast a low ratio and a lot of milk plus a little cream can make a delicious result.
One particularly memorable coffee was a Pacamara from Los Naranjos Café roasted by Cypher Roastery. The 1:1 ratio removed the bitterness leaving it sweet syrupy with a long finish. Delicious.
Espresso ‘Normale’ 1:2 ratio became a standard. That does not mean you should use it for every coffee roast level. Far from it.
Very light roasts can taste quite sour with insufficient extraction. The Espresso Lungo 1:3 ratio, and the Espresso Lungo Allongé 1:4 ratio is designed to deal with this.
If you have a very light roast and try using a fixed 1:2 or even 1:3 ratio, you will have put through far too little water under extracting. No amount of grind adjustment can compensate, and you will make a sour coffee. This is why most people don’t even try light roasts on espresso and use filter methods.
But they are missing out because you can have wonderful taste experiences with light roasts when extracted properly.
My partners favourite espresso was a Pacamara from El Gutalon in Guatemala roasted by Cypher Roastery. She described it as Lemon Sponge cake and unlike any coffee she had ever had. My notes were:
Wow, absolutely extraordinary. I’ve never had such a orange citrus coffee ever before. The nose is lovely, has some almond notes which I adore. The flavor is explosive, lively acidity is right. The roaster has done an excellent job of retaining all the terroir and avoiding any under development, the balance is spot on. The crip finish is just beautiful, I have a huge smile on my face for hours.
Don’t be afraid of light roasts on espresso, use the higher ratios.
Using the right ratio for the Roast Level, as indicated by the density, can make all the difference between success and failure.
Generally, if you are following the recipe you don’t need to know the ratio. But if for example you don’t have a full set of baskets, only an 18g, and a recipe is calling for a dose of 24g with a yield of 29g being a ratio of 1:1.2. You can keep the dose of 18g and use the ratio to calculate the yield 18×1.2=21.6g
With the same ratio the coffee will taste the same. With a smaller yield of 21.6g compared to 29g, scaling down the cup size from 240ml to 220ml would also be advisable.
Some people believe it is traditional to use only a 1:2 ratio for espresso.
Some more modern people believe it is better to use a 1:2.5 ratio.
Some people arbitrarily decide ristretto is their thing, or maybe decide lungo is where it is at.
All these statements are wrong. You need the right ratio to deal with the coffee roast level you have. Ratio is a tool, not a fashion choice.
A very dark roast done as a Lungo will be over extracted and bitter.
A very light roast done as a ristretto will be under extracted and sour.
Use the right ratio tool for the right extraction job.
If you are not using all the espresso ratios available to you, you are really limiting your ability to make better tasting coffee.