Espresso Extraction Tutorial: Parameter Adjustment and How to Judge Good Espresso

Those who run coffee shops understand the exhaustion of tasting espresso every morning until feeling drained, and the frustration of repeatedly adjusting the grinder without achieving the desired flavor.

Friends outside the industry may envy baristas for having endless coffee to drink, but only those in the industry know the bitterness... Perhaps FrontStreet Coffee can offer everyone some small insights (which might bring some relief).

From an enthusiastic netizen who wishes to remain anonymous

Understanding Why to Adjust Espresso

First, it's important to clarify why you need to adjust espresso. This is actually quite important, as there can indeed be aimless adjustments, adjusting for the sake of adjusting. FrontStreet Coffee has summarized that there are two main reasons for daily espresso calibration: the first is that today's extraction doesn't taste as good as yesterday's, so it needs to be adjusted back; the second is that the extraction has become unstable, with each cup potentially giving you "surprises," requiring parameter adjustments to stabilize it.

The Diagnostic Process

After clearly understanding the goal of adjusting espresso, the next step is "diagnosis" - why is this happening? After a 12-hour "rest period," the first espresso extracted every morning often has some issues. Sometimes these are minor detail problems that can be slightly adjusted or ignored without significantly affecting flavor and mouthfeel. In such cases, there's no need for major, rigorous adjustments. However, sometimes the espresso's extraction state, taste, and crema performance indicate that the coffee is abnormal (problematic), requiring adjustment.

In other words, it's not necessary to adjust every day. If the first three espressos extracted today meet the goals of stability and excellent flavor, then no adjustment is needed.

When problems occur in espresso extraction and the taste is off, there are many possible causes. Common reasons to consider include: ① Coffee bean oxidation; ② Grinder wear; ③ Changes in air humidity.

The process of resting coffee beans is a process of degassing and flavor loss. The change from the day before yesterday to yesterday might not be significant, but by today, there might be unacceptable flavor changes - similar to the "boiling frog" principle. In this situation, the espresso needs to be adjusted to bring out the best state of today's coffee beans.

Grinder wear is an overlooked detail, but FrontStreet Coffee has witnessed cases where a grinder was used for 3 years without disassembly, cleaning, or maintenance. The resulting espresso was indescribable. When disassembled, the accumulated coffee powder inside was unimaginable, and the burrs had developed burrs. Coffee ground by such a grinder producing good coffee is purely a matter of luck.

Therefore, regular cleaning of the grinder is a key task to ensure espresso stability.

Changes in air humidity - the most classic representative in the Lingnan region is the "return of the south wind" weather. Yesterday the air was relatively dry, but today the air is more humid, so adjusting the grind is inevitable because yesterday's parameters basically cannot be used.

When humidity is high, coffee grounds tend to clump, and instability can easily occur during extraction. The simplest approach in this situation is to increase the dose while keeping the yield the same. While this is a temporary solution, it's simple and practical.

Troubleshooting and Adjustment Methods

Now that we know these are the general types of problems that can occur, we can directly "treat the symptoms."

Generally adjustable parameters include grind size, dose adjustment, and ratio adjustment.

When calibrating espresso during morning opening preparations, adjusting the grind can be the first priority. Make corrections based on yesterday's parameters. For example, with the same dose and ratio, if there's a time error of more than 1 second, adjust the grind to reduce the error to within 1 second (adjust finer if time is faster, coarser if time is slower).

Next, of course, is to determine whether the espresso is normal through tasting. If it is, make another latte and taste that as well. If the latte shows bitterness and thin mouthfeel, you can adjust the coffee-to-liquid ratio by extracting less espresso liquid. Generally, the espresso extraction ratio of coffee grounds to liquid weight is 1:1.5-2.5 (excluding extreme cases).

The range of adjustment for increasing or decreasing dose is quite small. Generally, you need to consider the reasonable capacity of the portafilter basket. Adjustments are typically made based on previous parameters, with ±0.5g of coffee. If the adjustment exceeds this amount, it basically means overhauling the entire extraction approach.

Special attention should be paid to promptly replenishing coffee beans before using up the beans in the hopper, as hopper pressure can also affect grinding stability. When replenishing coffee beans, it's best to use beans with similar roast dates. If from different roast batches, it's recommended to use up one batch first, then add new coffee beans and perform testing and fine-tuning.

Important Notice :

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FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473