Consistently making a delicious espresso doesn’t rely solely on an expensive setup; it requires balancing the performance of the espresso machine, the quality of the coffee beans, the barista’s technique, and environmental conditions. This article explores these four key factors in detail, explaining how boiler capacity, water temperature, atmospheric pressure, bean varieties and storage methods, extraction time, dose and tamping technique, as well as temperature, humidity, and water quality affect flavor. It also retains product recommendations and parameter references related to “Front Street”, making it suitable for coffee enthusiasts who want to systematically improve the consistency of their output.

Taking today’s most popular espresso as an example, let’s go through the key points in the preparation process one by one. To get an outstanding cup of coffee, four conditions must be met at the same time: the performance of the espresso machine, the quality of the coffee beans, the human operational factors, and changes in environmental conditions. If any one of these falls short, it will affect the final result.

Choosing an espresso machine

1. Boiler capacity: If the boiler capacity is large enough, the water temperature will be relatively stable, and the coffee quality will be easier to keep consistent.

2. Espresso machine temperature: Whether the machine can maintain a stable temperature will likewise influence coffee quality.

3. Atmospheric pressure: Nine atmospheres is considered ideal for extraction.

4. Water temperature: International standards require the espresso machine’s water temperature to be 90°C, though the actual setting also depends on the roast level of the coffee beans. For darker-roasted beans, the machine’s water temperature should be lowered appropriately; otherwise the extracted coffee can easily develop burnt and bitter notes. The parameters used by SPR stores are suitable for keeping the water temperature between 90°C and 91°C.

It should be noted that the water temperature mentioned in coffee preparation refers to the water temperature at the group head, not the temperature of hot water output directly from the boiler.

Choosing coffee beans

1. Main characteristics of Arabica (also known as high-grown beans):

Strong aroma with pronounced intensity;

Less prone to bitterness;

Moderate Crema content;

Relatively high acidity;

Caffeine content is about 30% to 40% that of Robusta.

2. Main characteristics of Robusta:

Weaker aroma;

After dark roasting, it easily develops bitterness;

More Crema;

Lower acidity;

Very high caffeine content.

Storing coffee beans

1. Unopened coffee beans:

They should be kept in a cool and well-ventilated place, ideally at 18°C to 22°C. Try not to store them in an overly dry environment (below 54% humidity is too dry), so their storage conditions are relatively close to those for red wine.

2. Opened coffee beans:

Once coffee beans come into contact with air, their flavor begins to fade. Whole beans have a limited surface area exposed to air, but after grinding into powder, countless tiny surfaces are exposed to the air, and flavor loss speeds up noticeably. Therefore, when making coffee, try to grind fresh and use immediately so that every cup’s quality can be ensured. As for storing opened coffee beans, sealed storage is suitable, but do not place them in an overly humid environment, because coffee beans are afraid of moisture, and the oils are also easily lost, causing the flavor to deteriorate.

Key points for storing coffee beans:

Whether opened or not, coffee beans are afraid of excessively high environmental humidity.

Whether opened or not, the storage environment must not be mixed with various odors, and especially should not be placed in the refrigerator.

After coffee beans are opened, as long as the packaging is properly sealed again, using them within three days is acceptable, and no longer than five days at most, while still paying attention to the storage environment.

Coffee grounds that have already been ground are best used immediately.

Human factors

1. Base espresso:

A barista should know how to taste espresso, because as long as the espresso is made perfectly, the quality of other fancy coffee drinks is easier to guarantee. Espresso is the foundation of Italian coffee; therefore, to truly master espresso, you must first learn to drink and evaluate espresso.

2. Familiarity with the machine:

A barista must have a considerable level of professional coffee knowledge and professionalism, and must also understand the espresso machine being used well enough. Only by mastering the machine’s performance proficiently can a superior cup of coffee be made.

3. Professional preparation skills:

Only through professional training and repeated practice can one achieve correct and proficient operation, and only then can the quality of every cup of coffee be guaranteed.

4. Espresso extraction time:

For a 25cc to 30cc espresso, the standard extraction time is 25 seconds; however, between 22 seconds and 28 seconds can also be regarded as a reasonable extraction range, which allows better control of coffee quality.

5. Factors affecting espresso extraction time:

Selection of coffee beans and adjustment of grind size: Theoretically, dark-roasted beans are suited to a slightly coarser grind, and medium-roasted beans to a slightly finer grind, so adjusting grind size is one of the important factors.

Standard coffee dose: Generally speaking, each cup of Singer espresso uses 7g to 9g of coffee, depending on the barista’s positioning of the coffee’s flavor and the concentration preferred by consumers.

Tamping: When tamping coffee grounds in the portafilter, the pressure must be very accurate, and the coffee grounds must be tamped firmly enough to lock the portafilter onto the group head and extract espresso. When tamping, appropriate pressure should be used, and it should be pressed 3 to 4 times with a left-right rotating motion, which is more correct.

Changes in the environment

1. Changes in temperature:

The higher the outside temperature, the finer the coffee beans should be ground; conversely, grind coarser. Generally speaking, the ideal environmental temperature for coffee preparation is 18 to 23 degrees.

2. Changes in humidity:

The higher the humidity, the coarser the coffee beans should be ground. Compared with humidity, environmental temperature has a more major impact during coffee preparation.

3. Water quality requirements:

Generally, below 70ppm (the proportion of minerals in water) is soft water, and above 70ppm is hard water. The higher the mineral content in the water, the stronger the off-flavors produced during coffee preparation, so it is recommended to use water between 60ppm and 140ppm to ensure the coffee’s rich aroma.

The above content is compiled by CoffeeHunters, a coffee news website.