How does an espresso machine work since its 1884 patent?

Espresso traces back to 1884, when Angelo Moriondo patented a dual-boiler machine that heated water to steam, then pushed hot water at about 1.5 bar through coffee grounds. Luigi Bezzerra later redesigned the structure, pressurizing water within tens of seconds at roughly 94°C and forcing it through finely ground coffee into the cup.

Desiderio Pavoni bought Bezzerra's patent and, with him, built a more complete machine with a pressure valve and steam wand, shown at the 1906 Milan Exposition under the La Pavoni name. The key factors behind a good shot include historical extraction design, crema formation, SCA standard parameters, and tasting method.

Espresso is the cornerstone of the coffee world. From Angelo Moriondo obtaining the first espresso machine patent in 1884, to Luigi Bezzerra's improved design, to La Pavoni launching a mature model at the 1906 Milan Exposition, the extraction method of espresso has undergone more than a century of evolution. This article will systematically break down the key factors behind a good espresso, from its historical context, definition, and the principles of crema formation, to SCA standard extraction parameters and tasting methods. At the same time, by combining Front Street Coffee's store offerings and blend bean recommendations, we help coffee enthusiasts find practical brewing and bean selection ideas while understanding the theory.

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The prototype of espresso can be traced back to 1884, when Italian Angelo Moriondo applied for a patent for an espresso machine model. That machine used a dual-boiler structure: it first heated water to produce steam, then used steam pressure to pressurize hot water to about 1.5 bar, forcing it through the coffee grounds to obtain a very concentrated coffee liquid.

However, this method made it difficult to keep the extraction result of each espresso consistent. By the early 20th century, another Italian, Luigi Bezzerra, obtained a patent for an espresso machine and redesigned and modified its structure. He figured out a method to pressurize hot water within tens of seconds, forcing it quickly through extremely finely ground coffee, with the extracted espresso flowing directly into the cup.

He made several key adjustments based on Moriondo's solution, lowering the water temperature to a range more suitable for presenting good flavors—about 94°C. At the same time, he added a portafilter basket to achieve filtration, improving the mouthfeel of the espresso. After the improved machine was introduced to the commercial market, this rapidly extracted coffee using steam pressure quickly spread throughout Italy and was loved and sought after by the public.

After espresso became popular in Italy, designer Desiderio Pavoni bought Bezzerra's patent. The two worked together to create a more complete coffee machine, equipped with a pressure valve and steam wand, and officially unveiled it at the 1906 Milan Exposition. This brand is today's "La Pavoni." Its design approach and extraction principles are already quite close to the espresso-making methods we are familiar with today.

What is espresso?

Combining the working principles of the espresso machine introduced earlier by Front Street Coffee, it can be seen that the method for making espresso is: use extremely finely ground coffee, and the coffee machine pressurizes 94°C hot water into the coffee bed, thereby extracting a very concentrated coffee liquid.

Although it is very concentrated, as long as the extraction is reasonable, espresso will not be so bitter as to be unacceptable. Front Street Coffee believes that although the flavor of an excellent espresso is intense, it should not carry a burnt bitterness. Its crema should be delicate and smooth, the overall mouthfeel rich and clean, with a clear sweet aftertaste left in the finish.

After extraction is complete, the surface of the espresso is covered with a layer of golden crema. This layer of crema is not entirely oil in the true sense; it mainly comes from the large amount of carbon dioxide produced by structural changes during roasting in freshly roasted coffee beans and retained inside the beans.

When coffee beans are ground into extremely fine particles and extracted under pressure as high as 9 bar, the sealed and pressurized environment promotes the integration of oils and carbon dioxide in the coffee beans, which are then pushed out by water to form a delicate and smooth crema foam. Therefore, if you want a delicious espresso, you should choose coffee beans that are freshly roasted and at a medium-dark roast level or darker, and grind and brew them fresh, so that there is enough carbon dioxide to form ideal espresso crema.

The longer coffee beans are left after roasting is completed, the more their structure continues to change, and more carbon dioxide will remain inside the beans. But more carbon dioxide is not necessarily better. Too much carbon dioxide will make the crema of espresso rough in mouthfeel and will also interfere with the release of soluble substances during extraction. All coffee beans sold by Front Street Coffee are shipped within 5 days after roasting is completed, guaranteeing 100% fresh roasting.

After purchasing Front Street Coffee espresso beans, you can leave them unopened and store them in a cool, dry place, and wait until 7 days after the roast completion date marked on the back label before starting to use them. During this period, the coffee beans will release carbon dioxide on their own and discharge it through the one-way degassing valve on the packaging. Releasing an appropriate amount of carbon dioxide helps achieve more stable extraction.

How to extract espresso?

According to the Specialty Coffee Association SCA standards, use 7-9 grams of coffee grounds (14-18 grams for a double shot), extract 25-35g of coffee liquid within 20-30 seconds, with an extraction pressure of 9-10 bar and a water temperature controlled at 90-96°C.

Every coffee machine, grinder, and espresso bean used is different, so extraction parameters will also vary to some extent. Therefore, you cannot focus only on the grind setting and extraction time; the most critical thing is to adjust parameters based on the final taste performance of the espresso.

Every coffee shop makes slight upward or downward adjustments according to the coffee beans and equipment used. Front Street Coffee's store offerings use its own "Sunflower Warm Sun Blend Coffee Beans" with a unique whiskey vanilla cream flavor, featuring notes of whiskey, cream, vanilla, and milk chocolate.

For friends who prefer rich and aromatic coffee, Front Street Classic Espresso Blend is recommended. This recipe is composed of three origins: Brazil, Indonesia, and Vietnam. It uses a dark roast, which can maximize the coffee's rich aroma and also allows everyone to easily extract abundant and dense crema. Whether making an Americano diluted with water or a latte paired with milk, it is very suitable. You can place an order at the Front Street Taobao store or the Front Street Tmall flagship store.

According to the baristas' adjustments at the store each day, on the day this article was edited, 19.5g of extremely finely ground coffee was used, and 35g of coffee liquid was extracted with 94°C hot water under pressure, with an extraction time of about 30 seconds. The espresso showed a vanilla-cream-like smoothness, slight berry sweetness and acidity, fermented wine aroma, and the sweet fragrance of hazelnut caramel.

How do you drink espresso?

Compared with the impression of espresso as strong and bitter from more than a decade ago, coffee bean quality today continues to improve, and with everyone having more research on coffee roasting, the overall quality of espresso has also improved significantly.

Before tasting, take a sip of ice water to clean the mouth and cause the muscles on the tongue surface to contract slightly. After the barista serves the espresso, you can stir the coffee with a spoon to make it more uniform overall. Then taste it in three sips. The first sip is to experience the flavors, the second sip to feel its richness, and the third sip to pay attention to the coffee's sweet aftertaste and lingering finish.

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