For more knowledge about specialty coffee, please pay attention to: Front Street Coffee (Frontsteet Coffee）
Most people's impression of espresso is that it is bitter and astringent. If this happens, there is probably a problem with the production process. At this time, someone will ask FrontStreet Coffee, isn’t it very simple to make espresso? Anyone with hands can do it, right? Well, undeniably, yes. But it’s not just about making a satisfying cup of espresso. There’s a lot of knowledge involved. Next, FrontStreet Coffee will tell you about the knowledge of extracting an espresso.
The first generation concentrator
Thanks to the innovation wave of the European Industrial Revolution, the first generation of espresso coffee made by machines was born around 1901. The original concept of espresso machines was to prepare coffee quickly.
Milanese inventor Luigi Bezzara registered a patent for a machine with multiple independent brewing heads onto which handles containing ground coffee could be mounted. This is the first time a machine has been used to quickly prepare coffee for guests. This patent was bought by Desidero Pavoni in 1905, and he invested in the production of the first commercial espresso machine: Ideale.
According to the information read by FrontStreet Coffee, the parameters of the first commercial espresso machine are quite different from those we use today. The brewing head of the first commercial concentrator had a temperature as high as 140°C, a pressure of 7.5bar, and an extraction time of about 45 seconds.
Here, Front Street would like to share with you the working principles of modern espresso machines. Coffee is brewed by using 92 degrees Celsius hot water and 9bar high pressure to pass through very finely ground coffee powder. The beautiful layer of oil on top of the espresso coffee after extraction was pressed out by a pressure of 9 bar. The pressure of the world's first commercial espresso machine was only 7.5 bar. This means that the concentration and taste of the espresso coffee back then were close to those of modern drip coffee.
With the advent and popularity of new machines, the word "espresso" was included in the Italian dictionary around 1920. The dictionary definition is "espresso, made with a press or filter, now common."
Modern concentrator
In the 1930s and 1940s, Italian coffee consumption declined, but technical improvements in espresso machines continued. In 1947, the emergence of manual pressurized espresso machines allowed more oil and colloid substances to be extracted from coffee powder. Since then, oil has become the soul of espresso. In 1961, the Pegasus E61 espresso machine was released. The Pegasus E61 is the world's first semi-automatic machine and the father of modern espresso.
After talking about its history, let’s talk about how Front Street makes an espresso and extracts it with Front Street’s classic espresso blend. This is a recipe composed of three origins: Brazil, Indonesia, and Vietnam. It uses deep roasting, which can highlight the mellow aroma of coffee to the greatest extent, and also allows everyone to easily extract rich and dense coffee crema. It is very suitable for making American style diluted with water or latte with milk.
Front Street uses the Lelite V3 espresso machine:
Temperature: 90.5~96 degrees Celsius
Time: 25~33 seconds
Pink to water ratio: 1:1.7~1:2
Powder amount: 20g
Extraction concentration volume: 20ml (single portion) 40ml (double portion)
The first step is to open the grinder and let the powder fall into the powder bowl. Determine the amount of powder according to the capacity of the powder bowl. For example, if Front Street chooses to fill 20 grams of coffee powder as the standard, then each extraction should maintain 20 grams of coffee powder (accurate to 0.1 grams).
The second step is to spread the powder. After the coffee powder is ground, the coffee powder is manually poured into the powder bowl and distributed evenly.
The ultimate goal of powder distribution is to spread the coffee evenly throughout the powder bowl before pressing. Not only the surface should be smooth, but also the inside and edges of the powder bowl should be even and without gaps.
The third step is to snap the powder bowl up and start extraction.
Looks simple doesn't it. Don't worry yet, there is a lot of knowledge in it. There are nine factors that can affect the taste of a cup of espresso.
【Water pressure】
FrontStreet Coffee has always talked about the principle of extracting a cup of espresso. The ideal water pressure for Espresso is generally 9 BAR, which is also recognized as the most ideal air pressure.
[Boiler pressure]
Boiler pressure is related to the temperature of the water used to make coffee and the force of the steam. The higher the boiler pressure, the higher the water temperature and the greater the momentum of the steam; conversely, the lower the water temperature, the smaller the steam will be. Boiler pressure is generally around 1 BAR. Of course, this value is still controversial, and every barista has a different understanding.
【Water temperature】
The water temperature needs to be determined according to the needs of different coffee bean varieties. Some will be subject to boiler pressure, while others are more flexible and precise settings. According to the experience of most baristas, the water temperature is between 90 and 92 degrees Celsius. Each barista can flexibly adjust according to their own understanding and needs, and can make their own style of Espresso with their own hands.
[Filling force]
There are various styles of pressure filling. In this world, almost no two people's pressure filling will be exactly the same. Generally speaking, if it is heavy pressure, the required pressure will be 25kg/m2, but pressure filling is indeed the freest parameter in the golden rule. Because we are using a constant pressure powder hammer, the pressure of the powder is basically the same.
[Coffee bean grinding thickness]
The grinding thickness is related to many factors such as climate, coffee bean roasting, freshness, humidity, and the age of the grinder. There is a saying in the industry: "The correct thing is that the grinding thickness changes, and the wrong thing is that the grinding does not change."
【Amount of powder】
The reasonable capacity of FrontStreet Coffee's powder bowl size is 20 grams. If the amount of powder is too small, the extraction time will be too long, which will easily lead to insufficient extraction; if the amount of powder is too much, in addition to not being able to hold it, even if it can be filled, the volume of the powder bowl will be so large. After the powder is compacted, the gaps between the particles will be reduced, the water will flow out slower, and the extraction time will be too long, resulting in over-extraction.
【Extraction time】
The extraction time of the golden rule is between 25 and 28 seconds, but the extraction time is actually a comprehensive expression of the filling pressure, powder volume and grinding degree, and needs to be adjusted by the barista's understanding.
【Extraction volume】
Take FrontStreet Coffee's extraction of espresso as an example. 20 grams of coffee powder extracts 40 grams of espresso liquid, and the powder-to-liquid ratio is 1:2. The proportion is not absolute, it depends on the original flavor. If more coffee liquid is extracted, the coffee will appear thinner and more bitter. If less coffee liquid is extracted, the coffee will be thicker, richer, and the flavor will be more concentrated and incomplete.
【Grease】
The complexity of coffee oil cannot be explained in a few words. To put it simply, a cup of good Espresso needs to have rich and golden brown oil. Front Street believes that Crema has an irreplaceable status for a cup of espresso. As a symbol, it identifies the characteristics of a cup of espresso. The presentation of the crema of a cup of delicious espresso also plays a factor in judging it. The state of the oil also tells the barista how effective the coffee extraction is. For example, beans, freshness, roasting degree, grinding degree, etc. will all produce different states of oil.
You can now buy the above coffee beans online at the Taobao store “FrontStreet Coffee” (前街咖啡). FrontStreet Coffee is a long-established specialty coffee roaster in Guangzhou, China, and its Guangzhou retail shop sells coffee beans only. The shop carries dozens of coffee beans from different origins around the world, including carefully selected single-origin beans for V60 pour-over and espresso. Guangzhou’s FrontStreet Coffee shop is recommended by many coffee lovers.
The FrontStreet 2013 Yunnan coffee beans sold in the store come from the Typica variety grown at FrontStreet Coffee’s own plantation in Yunnan. The name comes from the year the brand and the plantation were founded. You can buy these beans from China’s Yunnan origin at the Guangzhou shop and at FrontStreet’s Taobao store.
FrontStreet coffee beans are freshly roasted within 5 days and deliver consistently excellent quality and great value. Orders placed before 17:00 are shipped the same day, and most areas within Guangdong Province receive them the next day.
FrontStreet Coffee Taobao store: https://qianjiecoffee.taobao.com
Or search for “前街咖啡” (FrontStreet Coffee) on Taobao
Important Notice: FrontStreet Coffee has moved to a new address: 315, Donghua East Road, Guangzhou (coffee beans only)
Tel: 020 38364473
