How Do European Imported Coffee Machines Shape Espresso Extraction

Espresso that tastes bitter and astringent usually points to a fault in extraction rather than the bean. A qualified shot depends on nine variables: dose, distribution, water pressure, water temperature, grind size, extraction yield, and crema condition among them. Modern European imported coffee machines run hot water at about 92°C through finely ground coffee at 9 bars of pressure.

The first machine-made espresso appeared around 1901, when Luigi Bezzara patented a multiple-brewing-head design in Milan; Desidero Pavoni bought the patent in 1905 and produced the Ideale commercial machine, which brewed at roughly 140°C, 7.5 bar, and about 45 seconds. Machines have since narrowed those ranges. Units from different makers, whether a European imported coffee machine or a nova coffee machine model, follow the same variables.

Espresso tastes bitter and astringent? The problem most likely lies in the extraction process. Front Street Coffee starts with the century-long evolution of espresso machines, sorts out the operating parameters of modern espresso machines, and uses the Lelite V3 as an example to fully demonstrate the process of making an espresso. From dose and distribution to water pressure, water temperature, grind size, extraction yield, and crema condition, nine key variables are broken down one by one to help you understand the technical logic behind a qualified espresso and find the adjustment direction that suits your preferred flavor.

Many people's first impression of espresso is bitterness and astringency. Once you taste this kind of performance, there is a high probability that something went wrong during the making process. So people often ask Front Street Coffee: Isn't making an espresso just something anyone can do? Indeed, the operation itself is not complicated, but if you want to consistently produce a satisfying espresso, there is far more to it than imagined. Next, Front Street Coffee will guide you through one by one and sort out exactly what knowledge is involved in extracting an espresso.

First-generation espresso machines The European Industrial Revolution brought a series of technological innovations, and the first machine-made espresso appeared around 1901. The original starting point of the espresso machine was very simple: to make coffee faster.

Milanese inventor Luigi Bezzara patented a machine equipped with multiple independent brewing heads, and during operation a handle filled with coffee grounds was installed onto the brewing head. This was the first time humans used a machine to quickly make coffee for customers. In 1905, Desidero Pavoni bought this patent and invested in producing the first commercial espresso machine: Ideale.

According to materials consulted by Front Street Coffee, the technical parameters of the first commercial espresso machine were quite different from the equipment commonly seen today. Its brewing head temperature reached as high as 140°C, the pressure was 7.5 bar, and the extraction time was about 45 seconds.

Here, Front Street will also briefly explain the working principle of modern espresso machines: hot water at 92°C passes through very finely ground coffee powder under 9 bar of high pressure, thereby extracting the coffee. The beautiful layer of crema on the surface of espresso is precisely the product of 9 bar of pressure. The world's first commercial espresso machine had a pressure of only 7.5 bar, which means that the espresso of that time was actually closer to today's drip coffee in concentration and flavor.

With the emergence and popularization of new machines, the word "espresso" was added to Italian dictionaries around 1920. The definition given by the dictionary was "espresso, made with a pressure machine or filter, now very common."

Modern espresso machines In the 1930s and 1940s, Italian coffee consumption declined, but technical improvements to espresso machines did not stop. In 1947, the manual pressure espresso machine was born, allowing more oils and colloidal substances in the coffee grounds to be extracted, and crema has since become the soul of espresso. In 1961, the Faema E61 espresso machine was launched. The Faema E61 was the world's first semi-automatic coffee machine and is also regarded as the father of modern espresso.

After reviewing the history, let's now talk about how Front Street makes an espresso. The equipment used by Front Street is the Lelite V3 espresso machine: Temperature: 90.5~96°C Time: 25~33 seconds Coffee-to-water ratio: 1:1.7~1:2 Dose: 20 g Espresso yield: 20 ml (single) 40 ml (double)

Step one, start the grinder and let the coffee grounds fall into the portafilter basket. The dose is determined by the capacity of the basket. For example, if Front Street uses filling 20 grams of coffee grounds as the standard, then every extraction should maintain 20 grams (accurate to 0.1 gram).

Step two, distribution. After the coffee is ground, manually load it into the portafilter basket and make it evenly distributed. This process is distribution. The core purpose of distribution is to spread the coffee grounds evenly throughout the entire basket before tamping, not only making the surface level, but also ensuring the interior and edges of the basket are even and free of gaps.

Step three, lock in the portafilter basket and begin extraction.

Does it look pretty simple? Not so fast, there is a lot of knowledge behind it. A total of nine factors affect the taste of an espresso.

[Water pressure]

Front Street Coffee has repeatedly explained the principle of extracting espresso. The ideal water pressure for espresso is generally 9 BAR, which is also the industry-recognized optimal pressure.

[Boiler pressure]

Boiler pressure determines the water temperature and steam force when making coffee. The higher the boiler pressure, the higher the water temperature and the stronger the steam force; conversely, when the water temperature is lower, the steam will also weaken. Boiler pressure is usually around 1 BAR. Of course, this value is still quite controversial even today, and every barista understands it differently.

[Water temperature]

Water temperature should be set according to the varietal needs of different coffee beans. Some are constrained by boiler pressure, while others can be flexibly and precisely set. Based on the experience of most baristas, the water temperature is between 90 and 92°C. Everyone can flexibly adjust according to their own understanding and needs, using their own hands to make an Espresso with personal style.

[Tamping force]

There are all kinds of tamping styles, and it is almost impossible to find two people in the world who tamp exactly the same way. Generally speaking, if heavy tamping is used, the required pressure is about 25 kg/m2, but tamping is precisely the most free parameter in the golden rules. Front Street uses a calibrated tamper, and the tamping force is basically kept consistent.

[Coffee bean grind size]

Grind size is related to many factors such as climate, coffee bean roast level, freshness, humidity, and the age of the grinder. There is a saying in the industry: "What is correct is that the grind size is always changing; what is wrong is keeping the grind unchanged."

[Dose]

The reasonable capacity of the portafilter basket used by Front Street Coffee is 20 grams. If the dose is too small, the extraction time will be too short, easily causing under-extraction; if the dose is too large, besides possibly not fitting, even if it barely fits, since the basket volume is fixed, the gaps between particles decrease after the coffee is compacted, the water flow speed slows down, the extraction time is prolonged, and ultimately over-extraction results.

[Extraction time]

The golden rule gives an extraction time of 25~28 seconds, but extraction time is actually a comprehensive reflection of tamping, dose, and grind size, and baristas need to adjust it according to their understanding.

[Extraction yield]

Taking Front Street Coffee's espresso extraction as an example, 20 grams of coffee grounds extract 40 grams of espresso liquid, for a coffee-to-liquid ratio of 1:2. This ratio is not absolute and depends specifically on the target flavor. Extracting more coffee liquid makes the coffee thinner and the bitterness more prominent; extracting less coffee liquid makes the coffee more viscous and rich, with a more concentrated taste but not complete enough.

[Crema]

The complexity of coffee crema cannot be fully explained in just a few words. Simply put, only a rich, golden-brown crema can be considered a good Espresso. Front Street believes that Crema has an irreplaceable place in an espresso. As a symbol, it marks the characteristics of an espresso, and for a good-tasting espresso, the appearance of its Crema is also one of the judging factors. The condition of the crema also tells the barista how well the coffee was extracted. For example, beans, freshness, roast level, and grind size will all produce crema in different states.

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