Basic Espresso Theory
Focus on these three variables to build a solid espresso foundation.
Basic Espresso theory is made up of three variables. Each represents a different variable that builds on the other—brew ratio, brew time, and brew temperature. There are other variables that impact espresso, but focusing on these three will help you build a solid foundation in your at home routine.
The first variable is Brew Ratio: the amount of ground coffee (in) to water (out), measured by weight. Brew ratio affects the mouthfeel of your espresso more than any other factor, and is a somewhat personal preference. Changing your ratio will give you a different mouthfeel and taste. The smaller your ratio, the more thick and viscous your espresso will be. The larger your ratio, the more stretched-out and thin your espresso becomes.
Borrowing language from Italian espresso nomenclature, a 1:1 to a 1:2 is a Ristretto espresso, 1:2 to a 1:3 is a Normale espresso, and a 1:3 to a 1:4 is a Lungo espresso. There is wiggle room for interpretation here. For context, a cup of drip coffee from a coffee maker is around a 1:15 ratio.
Measuring brew ratio is easy. Weigh the amount of ground coffee that goes into the portafilter, then weigh the amount liquid espresso that flows into your cup, in real time. The size of your portafilter basket will determine how much coffee you should be putting into your portafilter. Typically, you can dose +/- 2 grams of coffee in the prescribed basket amount.
If you aren’t sure what your brew ratio preference is yet, a 1:2 ratio (say, 18g in and 36g out) is a great place to start. From there, you can hone in and tweak your espresso to your liking.
A good exercise to show the affect brew ratio has on an espresso is to try the same coffee pulled as a 1:1, a 1:2 and a 1:3. Focus on things like mouthfeel, clarity, and any notes you can pick up and see how (or if) they change from ratio to ratio.
Quick thoughts on Brew Ratios:
- Brew ratio help you determine the style of espresso you’re making, and gives you a starting place—it’s not a complete recipe, though.
- Choose a brew ratio before pulling a shot. This gives you a roadmap to follow and baseline for making adjustments. A 1:2 ratio (18g in, 36g out) is a good place to start.
- Generally, darker-roasted coffees perform well with a smaller ratio, while lighter-roasted coffees perform well with a larger one.
- The size of your portafilter basket dictates how much coffee to grind into the portafilter. The rule of thumb is +/- 1-2 grams of coffee for whatever basket size you’re using.
- If you’re at a café and enjoy an espresso, ask the barista what their brew ratio was
Brew Time is the second variable in basic espresso theory: how long it actually takes to reach your desired brew ratio. If you are using 18g of coffee in, and aiming for 36g of liquid espresso out, grind size dictates the time it takes to reach your ratio.
Picture a jar of marbles and a jar of sand. If you pour water into the jar of marbles, the water falls straight to the bottom of the jar. If you pour water into the jar of sand, the water will take much longer to reach the bottom. The jar of marbles represents a coarse grind and the jar of sand represents a fine grind.
Giving water time to interact with coffee grounds allows for extraction to occur. As water hits ground coffee, it begins to pull out salts, acids, sugars, and bitters—in that order. If your ratio is achieved too quickly you will need to make your grind finer, if too slowly you will need to adjust coarser.
The targeted time that you should be trying to achieve your brew ratio is typically 25 – 35 seconds.
Once you have achieved your brew ratio in the proper brew time, you can start to make adjustments to the flavor using brew ratio as your macro adjustment and brew time as your micro adjustment. As a general rule, a longer brew time will result in more body and complexity and a shorter brew time will result is less body and less complexity in the cup.
It is important to master the relationship between Brew Ratio and Brew Time before making adjustments with Brew Temperature—the third variable. Brew Temperature should be used mainly as a way to adjust the flavor of espresso in a machine that keeps temperatures extremely consistent. For the most part, setting your espresso machine at a brew temperature of 200 °F / 93 °C will give you good results. You can think of Brew Temperature as a way to adjust to different roasts and brew ratios.
Normally, light roasts and larger brew ratios will require higher brew temperatures, whereas darker roasts and smaller brew ratios will require lower brew temperatures.
By using these Basic Espresso Theories you will start to learn how to manipulate the flavors of your espresso. This is the true goal of the barista, to find the sweet spot in any coffee that they brew.
Explore brew ratios, recipes, and hone your espresso-making skills using the links below.