To make an outstanding espresso, the choice of coffee beans and the extraction parameters are both indispensable. Front Street Coffee starts with the differences between roast levels, blends, and SOE, sorts out four espresso blend options with different positioning, and analyzes one by one how the six major parameters—dose, brew ratio, extraction time, flow rate, pressure, and water temperature—affect the taste of Espresso. Whether you are practicing at home or selecting beans for a coffee shop, this experience can help you avoid common pitfalls and find a stable, on-point solution.

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Front Street Espresso is a coffee beverage with a strong taste. It is made by using hot water at about 92°C and 9 bar of high pressure to rush through finely ground coffee to extract the coffee liquid. Many customers are at a loss when buying coffee beans and do not know how to choose. Front Street Coffee (FrontStreet Coffee) will discuss how to choose coffee beans.

Front Street's approach to choosing espresso coffee beans

Roast level: Let's start from this angle. Whether it is single-origin coffee beans or blended coffee beans, we should first pay attention to its roast level. Espresso is not suitable for using some relatively light-roasted coffees. Light-roasted coffee retains more acidity and has less crema. If used as espresso, it will be a cup of sharply acidic, thin coffee. For example, many single-origin coffee beans on the market specifically for pour-over coffee are actually not very suitable for espresso.

When purchasing generally, please read clearly the roast level on the coffee beans or whether it is marked as suitable for espresso machines.

Blended coffee and SOE coffee: The full name of SOE is "Single Origin Espresso," translated as single-origin espresso. This concept exists relative to blended espresso. Although SOE stands for single-origin espresso, it does not necessarily equal specialty coffee. If you choose single-origin coffee beans with easily recognizable and strong flavors as SOE, you can create an espresso with a unique and typical flavor.

At the same time, the characteristic of "single origin" is also a factor that can become a disadvantage. If you choose coffee beans with insufficient flavor intensity or with unpleasant flavors, it will also be amplified in espresso, making it easier to taste the defects and bad flavors in it. Therefore, stricter requirements are needed for the barista's sensory evaluation and for SOE bean selection.

Blended coffee: Blended coffee, also called mixed coffee, is the mixing of various single-origin coffee beans together, thereby fully bringing out the strengths of each single-origin coffee bean. Blends are made by mixing coffee beans from different origins to create a more balanced taste.

Coffee is an agricultural product, so even for the same type of coffee bean, its flavor can differ from year to year. Therefore, mixing several coffee beans together solves this problem very well. When a certain coffee bean in the blend does not meet expectations in flavor in the new crop season or is in short supply, it can be adjusted by replacing it with coffee beans of similar flavor.

The advantage of blended coffee lies in its ability to use the flavor characteristics of different origins to complement each other, forming a stable flavor, and it also has a clear advantage in price.

Front Street espresso coffee bean blend options

Depending on the type of coffee, the espresso coffee beans prepared will also have different characteristics in taste and flavor.

1. Front Street Basic Espresso Blend Coffee Beans, characterized by affordability Formula: Brazilian Red Bourbon beans (70%), Yunnan small-bean coffee beans (30%).

This espresso coffee bean focuses on high cost-effectiveness. Front Street uses a blend of all-arabica beans from Brazil and Yunnan, China. On the premise of price advantage, it ensures that the extracted espresso has the classic nutty creamy aroma and the charm of dark chocolate. It is suitable for personal daily consumption or low-cost coffee bean use, and is also suitable for opening a shop and household users who prioritize cost and have average flavor requirements.

2. Front Street Commercial Espresso Blend Coffee Beans, characterized by rich aroma and abundant crema Formula: Colombia (30%), Brazil (60%), Robusta (10%).

Considering the diversity of the audience, Front Street needs to choose coffee beans with rich flavors to create a strongly flavored blend. Such coffee beans include Colombian coffee beans with a rich nutty chocolate flavor, Brazilian coffee beans with mild bitterness, and Robusta coffee beans, which are mainly known for their full body and rich crema. The coffee beans prepared in this way have a relatively heavy bitterness and are deeply loved by coffee enthusiasts, and can meet daily shop needs.

3. Front Street Specialty Espresso Blend Coffee Beans, high-quality and classic Formula: Brazil (70%), Colombia (30%). The traditional classic espresso flavor is a rich nutty chocolate tone. Front Street takes this classic flavor as the taste goal of this blend formula. To have an outstanding flavor, high-quality arabica coffee beans must be selected. Front Street uses a blend of arabica coffee beans from Brazil and Colombia. The balance and nutty tone of Brazilian coffee beans, together with the full body of Colombian coffee beans, give this blend a good performance. The priority of the blend is both stability and flavor. The espresso produced has rich and delicate crema, a full body, and a nutty main tone with a slight fruity acidity. It is suitable for some specialty coffee bean uses and can also meet the daily output needs of coffee shops.

4. Front Street Sunflower Warm Sun Espresso Blend Coffee Beans, with the distinctive flavor of specialty coffee Formula: Front Street Honduras Sherry (70%), Front Street Yirgacheffe Red Cherry (30%).

Front Street named this uniquely flavored Front Street espresso coffee bean Sunflower Warm Sun. As the name suggests, the aroma of this Front Street espresso blend is as comfortable as warm sunlight, and the taste and flavor are eye-catching. With the richly fermented winey aroma of Front Street Honduras Sherry coffee beans as the main body, paired with Front Street Yirgacheffe Red Cherry coffee beans, which are known for their acidity, it can create a aromatic and rich blended coffee.

As with the extraction parameters of pour-over coffee, espresso pays even more attention to extraction parameters. The following will separately explain and analyze coffee dose, brew ratio, extraction time, flow rate, extraction pressure, and extraction temperature.

Coffee dose

The amount of coffee grounds is determined by the capacity of the filter basket. For example, some coffee machine manufacturers provide double filter baskets in several specifications such as 16g, 18g, 20g, and 22g, and these specifications are recommended capacities, with a maximum filling error of ±1g. For example, using an 18g filter basket, a reasonable dose range can be 17-19g.

Front Street does not recommend a dose that is much less or much more than the size of the filter basket. The amount of coffee grounds affects the density of the puck. Under the same tamping force, too little coffee grounds will be relatively loose, causing the flow rate to be faster and resulting in under-extraction. Conversely, it will be denser, the flow rate will be slower, and it may even be difficult to extract coffee liquid.

Brew ratio

Espresso uses the ratio of coffee grounds to espresso liquid, because you cannot calculate how much water was used for extraction. Of course, some new coffee machines install a meter at the water inlet to display the water amount. The original extraction ratio was the single-shot espresso standard, with 7-8g of coffee grounds extracting 25-30ml of espresso liquid. The former is a unit of weight, and the latter is a unit of capacity (volume). Only when the density is consistent are the two equivalent, but we all know that the extracted espresso has golden crema, and the thickness of this crema depends on the roast level and freshness of the coffee. Therefore, using this measurement method will cause instability in the output.

That is why the ratio of coffee dose to liquid weight appeared. It is generally between 1:1.5 and 1:2.5, and the more common ratio is 1:2, such as 20g of coffee grounds extracting 40g of coffee liquid. The ratio is affected by two factors: one is the dose, and the other is the water amount. A ratio that is too low will make the coffee taste very rich and heavy, and it is prone to the bitter taste brought by over-extraction. Conversely, a ratio that is too high will taste weak and bland, as well as sharply acidic due to under-extraction.

Extraction time

Time refers to the entire extraction time from locking in the portafilter and pressing the extraction button to the end of extraction. The factors affecting extraction time are, first, the grind size, and second, the ratio. The ratio is easier to understand: a higher ratio requires more water for extraction, so the time will naturally be longer. Grind size affects the coarseness or fineness of the coffee grounds, and the degree of coarseness or fineness directly affects the density of the coffee puck. The finer the coffee grounds, after tamping, the denser the puck, the harder it is for water to pass through, and the longer the time, which easily leads to over-extraction. Generally speaking, the time to extract one espresso is about 20-30 seconds.

Flow rate

Flow rate is the speed at which the coffee liquid flows down. The ultimate goal of our extraction parameters is actually the result of the flow rate. For normal espresso, the first drop of coffee liquid usually needs to begin dripping about five seconds after pressing the extraction button, and the subsequent flow rate is relatively even. The speed of the flow rate directly reflects whether the grind size and ratio are appropriate. If it takes more than 10 seconds (excluding pre-infusion) for the first drop of coffee liquid to appear, then the grounds may be too fine, or the tamping may be too dense. If the flow rate is too fast or there is spraying, then the grounds are too coarse, or channeling has occurred.

Extraction pressure

Generally speaking, the extraction pressure of a semi-automatic coffee machine is around 9 bar, which is determined by the performance of the coffee machine. Some coffee machines now have pressure-profiling extraction functions. Low pressure results in low extraction efficiency, while high pressure results in high extraction efficiency.

Extraction temperature

The water temperature for extracting espresso is generally between 90 and 94°C. If the water temperature is too high, it is easy to over-extract, and the coffee taste tends to be bitter. If the water temperature is too low, it is easy to under-extract, resulting in a sharply acidic coffee taste.

Combined with Front Street Coffee's many years of output experience, in addition to the above key points, a high-quality espresso is also affected by the following factors: the freshness of the coffee beans, whether the distribution is even, the tamping force...

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