Espresso is a coffee beverage obtained by Italians using a pressurized coffee machine to quickly extract at high temperature and high pressure in a short time, with a golden foam layer on its surface. Different stores use different espresso beans and extraction schemes, so the final flavor will vary noticeably, but a standard espresso usually has two common characteristics. This article will start from the formation principle of crema, explain the relationship between its color and coffee bean freshness and roast degree, then discuss the reasons for its high concentration, and, using Front Street Coffee store output as a reference, introduce in detail the complete production process from dose, ratio, and time to specific operations, helping coffee enthusiasts stably extract an ideal cup of Espresso at home as well.
Espresso, called Espresso in English, is a coffee beverage obtained by Italians using a pressurized coffee machine to quickly extract at high temperature and high pressure in a very short time, with a golden foam layer covering its surface. Each store uses different espresso beans and different extraction schemes, so the final flavor presented varies, but a qualified espresso usually has the following two common characteristics.
Cream (coffee crema)
When we order an espresso at a coffee shop, the barista finishes extracting and immediately brings it to the table, and we can observe a thick golden foam floating on top of the liquid. This is what we call crema.
Coffee beans generate a large amount of gas during the roasting process. Under high pressure, water dissolves out the carbon dioxide among it, but once the brewed coffee liquid returns to normal pressure, it can no longer continue to lock in all the gas components, so countless tiny bubbles surge out from the liquid. These bubbles remain on the surface of the coffee liquid, looking like a stable layer of “bubbles.” A rich and dense crema indicates that the coffee beans used for this espresso were freshly roasted. This is because the gas inside coffee beans continues to be released over time; the longer since the roast date, the less carbon dioxide remains, and the thinner the foam layer formed during extraction.
If an espresso has no crema on its surface, it is most likely because the coffee beans have been stored too long, or because the espresso was not consumed for a long time after being made and the foam has already dissipated. The darker the color of the crema, the stronger the taste usually is. This is because the coffee beans undergo the Maillard reaction at high temperatures; beans with a darker roast level have a darker foam layer and a richer mouthfeel.
High concentration
The extraction of a single espresso requires the release of a large amount of soluble substances in just a few dozen seconds, so the coffee grounds must be ground extremely fine and uniform. Through the action of near-boiling hot water and strong pressure of 9 atmospheres, the concentration of espresso is quite high, and all flavors are concentrated many times over, presenting a strong impact on the palate. After swallowing, the various aromas remain in the mouth, with a lasting finish. For this reason, many coffee shops serve a glass of water alongside a strong espresso when presenting it.
How to make espresso
Many coffee enthusiasts have unknowingly added all kinds of coffee equipment at home, and friends who love Italian coffee have even bought espresso machines, planning to extract it themselves. Here at Front Street Coffee, using store-produced espresso as a reference, we will briefly explain how to make an Espresso.
The coffee machine used at Front Street Coffee stores is the commercial single-group “Lelit Bianca,” which can adjust extraction by changing pressure, with a maximum pressure of up to 11 bar. As long as a home coffee machine can reach 9 bar of pressure, it is enough to meet the needs of extraction and milk frothing, and pairing it with an espresso coffee grinder is all that is needed.
Front Street Coffee uses the capacity of a double basket, with a dose of about 18–20 grams; Front Street Coffee uses 20 grams of coffee grounds when producing. Usually the ratio of coffee grounds to coffee liquid is controlled at 1:1.5–1:2.5. Front Street Coffee’s extraction ratio is 1:2, that is, 20 grams of coffee grounds extract 40 grams of coffee liquid. Time is related to the flow rate of the coffee grounds. Generally, a single extraction duration is controlled at 20–35 seconds, because within 20 seconds the coffee often tastes thin, while exceeding 35 seconds makes over-extraction likely, producing a burnt bitter taste. Front Street Coffee’s espresso mostly falls in the range of 28–30 seconds.
Front Street Coffee first wipes the basket dry, turns on the grinder, grinds the amount for a double shot of coffee grounds, places it on an electronic scale, and increases or decreases until it reaches 20 grams. Then use a tool to distribute the grounds evenly and tamp the coffee puck firmly to ensure more stable extraction. Next, turn on the extraction switch to release water, wetting the brew head while carrying away the coffee grounds adhering to it, gently lock the portafilter onto the brew head, and flip the switch down to begin extraction. When the electronic scale shows that 40 grams of coffee liquid has been extracted and the time is about 30 seconds, the extraction switch can be pulled down. Pour the coffee liquid into an Espresso cup and enjoy.
The taste and mouthfeel of Espresso depend on the coffee beans used. It is recommended to use Front Street Coffee Classic Espresso Blend. This is a recipe composed of beans from 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 coffee crema. Whether making an Americano diluted with water or a latte paired with milk, it is very suitable. It can be purchased and ordered at the Front Street Coffee Taobao store or the Front Street Coffee Tmall flagship store.
The above content is compiled by CoffeeHunters, a coffee news website.
