How does the espresso machine work across ristretto, normale, and lungo?
Espresso is brewed by forcing hot water under high pressure through finely ground coffee packed into the portafilter basket, and the whole shot finishes in a short time. The golden crema on top comes from oils emulsifying the gas released from fresh beans. Extraction yield splits espresso into three types: ristretto, normale, and lungo, which differ in concentration, flavor, and mouthfeel.
Baristas adjust the brew ratio, grind size, and water temperature daily, since most Italian-style drinks rest on that single shot. A qualified espresso needs sufficient pressure and water temperature, an appropriate dose, a relatively fine grind, and a short extraction time. These are the core elements of coffee extraction that separate espresso from pour-over and cold brew.
Espresso is the foundation of the Italian coffee system, and for many coffee enthusiasts, it's something they both love and fear. It is extracted in a short time through high temperature and high pressure, and the golden, dense layer of Crema on its surface is its hallmark. Depending on the extraction yield, Espresso can be divided into three types: Ristretto, Normale, and Lungo, each differing in concentration, flavor, and mouthfeel. This article will systematically sort out the core knowledge of espresso, from its definition and type classification to extraction parameter adjustment, and share Front Street Coffee's practical experience with brew ratio, grind size, water temperature, and more, to help readers gain a more comprehensive understanding of the intricacies behind this small cup of coffee.
When people hear "espresso," many may picture a dark coffee that is intense, strongly bitter, and harsh. For baristas, adjusting espresso extraction parameters every day is arguably one of the most essential tasks, because almost all popular Italian-style drinks are built on that small shot of espresso. Today, Front Street Coffee will talk about what espresso actually is and the differences between the various espresso types.
Definition of Espresso
Espresso refers to the coffee liquid obtained by finely grinding coffee beans, loading an appropriate dose into the portafilter basket, and extracting it in a short time under high temperature and high pressure using a semi-automatic or automatic espresso machine. According to this definition, a qualified cup of espresso needs to satisfy several elements at the same time: sufficient pressure and water temperature, an appropriate dose, a relatively fine grind, and a relatively short extraction time.
What sets espresso apart from other extraction methods such as pour-over and cold brew is the layer of fine golden foam on the surface, known as Crema. Freshly roasted coffee beans accumulate a large amount of gas inside. During extraction, the coffee grounds are immersed in hot water and subjected to higher pressure, and the gas expands when heated and is pushed out of the cell walls. At the same time, the coffee substances dissolved by the hot water contain oily components, and these oils wrap around the released gas through emulsification, thus forming a dense layer of bubbles. Crema is composed of vegetable oils, proteins, sugars, and some aromatic substances, so freshly extracted espresso often has a rich aroma.
Classification of Espresso Types
The golden cup theory proposed by the Specialty Coffee Association of Europe holds that after water comes into contact with coffee grounds, about 30% of the soluble substances will be released, while the remaining 70% consists of large-molecule woody structures that cannot dissolve. Of that 30%, only about two-thirds are molecules with better flavor performance, so key parameters need to be adjusted to keep the extraction yield roughly around 20%. In terms of extraction method, Espresso can be subdivided into three types: Ristretto (short extraction), Normale (regular), and Lungo (long extraction). All three are espresso liquids quickly extracted using an espresso machine.
Ristretto
Ristretto is generally translated as Italian-style extra-concentrated coffee, and is also called refined extra-concentrated coffee. Compared with the common Espresso, Ristretto is more niche, and the familiar Flat White is made with Ristretto as its base. Ristretto means "restricted" in Italian, which can be understood as limiting the amount of extraction liquid and taking only the front and middle stages of the espresso, thereby increasing the coffee's concentration.
For example, Front Street Coffee's Espresso extraction recipe is 20 grams of coffee grounds yielding 40 grams of coffee liquid, with a brew ratio of 1:2, taking 30 seconds. When making Ristretto, however, only 70% of the Espresso is taken, that is, 20 grams of coffee grounds yielding 28 grams of coffee liquid, and the time is shortened accordingly. In addition, the flow rate can be slowed by making the grind finer, further increasing the concentration of the coffee liquid. Different coffee shops will make corresponding adjustments based on the characteristics of the coffee beans they use and the flavor and mouthfeel the barista wants to present.
Normale
Normale is the most common and most widely accepted espresso on the market, and is essentially what is usually called Espresso. At present, most shops produce mainly Normale, though they do not specifically emphasize it. According to golden cup standards, Normale's extraction yield is between 18% and 22%, with a concentration range of 8% to 12%.
Lungo
Lungo is coffee made with twice the normal amount of water. "Lungo" means "long, extended" in Italian, so it is also called "stretched espresso," meaning that by extending the extraction time, the coffee concentration is lowered and the taste is softer.
After repeated adjustments and tasting trials, Front Street Coffee ultimately settled on a brew ratio of 1:5 for Lungo. Specifically, using 20 grams of coffee grounds, the extraction time is extended to 42 seconds, extracting 100 grams of coffee liquid.
Notes on Extracting Espresso
The golden Crema floats on top of the coffee liquid. This is the result of carbon dioxide and other gases in fresh coffee beans dissolving into the water under high pressure. If coffee beans that have been stored too long (more than 2 months) are used, it is difficult to extract an Espresso with an ideal crema state, so Front Street Coffee recommends choosing freshly roasted coffee beans and resting them properly. The coffee beans shipped by Front Street Coffee are all confirmed to be freshly roasted within 5 days, so that they still maintain good freshness when you receive them. Coffee beans need a period of degassing after roasting is completed. Because espresso beans are mostly medium-dark roasted, such as the Sunflower Warm Sun blend coffee beans used by Front Street Coffee shops, they need 7 to 10 days to release carbon dioxide. Using properly rested coffee beans to make espresso not only gives a fuller aroma, but also makes the extraction process more stable.
To extract a delicious cup of espresso, there are countless parameters involved in the settings. Front Street Coffee believes that the main key factors to grasp are: coffee dose, grind coarseness, temperature, extraction time, and extraction liquid weight. For example, when espresso tastes somewhat thin in flavor, the extraction yield needs to be increased, which can be achieved by increasing the dose, making the grind finer, and raising the water temperature; conversely, if the espresso's heavy bitterness is too strong, the extraction yield should be reduced, which means decreasing the dose, making the grind coarser, or lowering the water temperature. No matter which adjustment method is used, the ultimate goal is to extract an espresso with a full aroma.
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The above content is compiled by CoffeeHunters, a coffee news website.
