In this module you will learn all about preparing the proper espresso
The foundation for our menu begins with proper espresso, and a barista must understand all aspects of espresso preparation. Module 2 takes us through espresso preparation from roasted coffee to the final cup. In this module, we will cover espresso grinding, dosing, distribution, tamping, and espresso extraction.
Module 2 Overview
In Module 1: Lesson 3, you learned about the importance of espresso grinders. In this lesson you will learn about their operation.
A great barista strives for efficiency and reducing waste in preparation techniques. The goal is always to grind only as much coffee beans as is needed to prepare each drink. Once the coffee is ground, it will immediately start to lose freshness through oxidation due to the amount of surface area now created through the grinding process.
To begin grinding, fill the hopper with whole bean coffee and be sure the bean release door is open. Turn the grinder on.
For doser type grinder operation, start to move the doser handle immediately. Try not to leave any excess grounds in the doser between uses. Turn off the grinder just before you reach the total dose, then finish dosing.
For doserless grinding, refer to manufacturer advice on timer adjustment. Set the timer so the grinder only dispenses the desired amount of coffee. Keep in mind that grind adjustments will impact the total dose.
-Adjusting the grind coarser will result in an increased dose because larger particles are faster to cut.
-Adjusting the grind finer will result in a decreased dose because smaller particles take more time to cut.
Be sure to use a scale to double-check that your dose is correct after grind adjustment.
We will cover maintenance and cleaning in more detail in other modules, but keep in mind that the espresso grinder plays a critical role in the quality of drinks. The importance of condition and cleanliness cannot be understated.
Dosing & Distributing
Dosing is the act of filling the portafilter with ground coffee. Once you’ve filled the portafilter so it is slightly heaping with grounds, it’s time for distribution.
Distribution is the process of evening out and evenly distributing the grounds in the basket.
The purpose of distribution is twofold:
- To facilitate even compression of the grounds during tamping.
- To reduce excess waste and overdose.
This is a manually-performed technique using your hand or finger. The sensitivity of touch is crucial to consistency here.
Even dose control and proper distribution are two of the Barista’s most fundamental challenges. But consistent dosing and distribution improve quality and consistency by removing a major variable and setting the barista up for a perfect tamp. And proper dose control improves profitability, because of minimizing waste.
In this lesson, we will describe a simple, repeatable distribution technique using three quick passes over the portafilter.
With a small mound of fresh ground coffee in the basket, place your index finger, palm facing down, on the edge of basket closest to the handle.
Push your index finger forward and plow the mound of grounds up to the front edge, but not off. Lift your finger and place on the other side of the mound, on the edge of the basket.
Now plow the mound back toward the handle, but not off. let you finger slide along the top of the basket as a guide.
On the third pass, push the mound forward again and push any excess grounds off. Excess grounds could be swiped into the knock-box or the dosing chamber. Only place grounds in the dosing chamber if they will be used immediately.
Distribution How To's
Perhaps the most iconic image of the working barista is the tamper in hand. Barista techniques have centered around this tool for a long time. In Lesson 3, we discuss techniques and develop standards for consistent and proper tamping.
Hold the tamper like a flash light or a door knob, not like a golf club or a pepper grinder. Tamping force is applied to the base of the tamper, not the handle. Let your thumb and index finger fall low and wide, on the base and not the handle. Keep a straight wrist — your elbow should be directly over the coffee, not off to the side.
Contrary to popular belief, the difference in flow resistance caused by lighter or harder tamping is negligible. Tamping pressure is relieved as water saturates the coffee grounds. Baristas typically aim for between 30 and 50 pounds of tamping pressure. Espresso machines are normally configured to dispense 9 bar, or approximately 130 pounds per square inch, of water pressure. This easily overwhelms the tamping pressure.
The force required to really affect the espresso is excessive and places the barista at risk of repetitive stress injuries. This leads us to the conclusion that a lighter tamping technique is both more consistent and safer. Level tamping and final polish are more important in preparing the basket of coffee grounds for an even extraction.
*For reference: a barista’s tamping pressure, as measured across the surface of the coffee would be (30lbs)/(4.09in^2)=7.3psi of tamping and at (50lbs)/(4.09in^2)=12.2psi.
The primary goal of tamping is consistency. Other advantages of tamping include:
- Keeping the group head cleaner, and
- Reducing waste.
Extraction & Dialing In
Let’s look at a properly extracted espresso. You’ll need to understand some basic rules and parameters to achieve a consistent and proper extraction .
We’ve already learned about the importance of consistent espresso dosing. In this lesson we will learn about the other variables that affect the flow of espresso.
Here are some of our most important observations when assessing espresso during extraction:
Dose: 18–20 grams (0.5-0.8 ounces)
Drop Time: 5-7 Seconds
Stream flow: Drip…drip…drip…stream
Viscosity: Syrupy, rich, warm honey
Color: Dark, rich, browns, reds, rusty
Color Change: Blonding, yellowing, lighter
Volume: 50-80ml (1.25-2.5 ounces)
Total Time: 25-30 Seconds
For the examples in our video presentation we will assume consistent dosing, distribution and tamping.
Important details for Dialing In
It’s important for a barista to consider many factors while assessing espresso. If, for example, you measure espresso only by volume, you find a condition where brewing 2 ounces in 30 seconds is considered the same as brewing 2 ounces in 15 seconds. In reality they taste very different. When the espresso deviates from our ideal extraction parameters we must consider these observations, along with taste profile, to decide what to do.
If the drop time is too short (your espresso drops in 4 seconds or less), if the streams flow fast immediately, if the espresso is watery and light in color, or if you reach 2 ounces in 20 seconds or less, the grind is too coarse.
If the drop time is too long (if your espresso drops in 9 seconds or later), if the streams drip continuously, if the espresso is thick and black or if you reach half an ounce in 25 seconds, the grind is too fine.
Once the coffee is in the machine, it’s time to brew! In this lesson, baristas learn to operate the machine as well as diagnose problems with brewing.
Always remember that tasting is critical and coffee is complex. We are trying to control chaos and manage multiple variables to achieve a consistently good tasting espresso extraction.