How Do Espresso Coffee Beans Affect Extraction and Flow Rate?

Standard espresso extraction follows internationally accepted figures: about 7 grams of freshly ground coffee, water at roughly 92°C under about 9 bar of pressure, a 20 to 30 second extraction, and 20 to 30 milliliters of liquid topped with crema. The article then compares these numbers with a practical house standard of 19 grams in, 38 grams out, a 1:2 ratio in 28 seconds.

Flow rate is the practical signal for judging a shot. When extraction runs too fast or too slow, dose, grind, ratio, time, pressure and water temperature all give clues to the adjustment needed. The article also covers how blend coffee and single-origin espresso products differ in formulation, flavor and suitable use, plus advice on roast dates and peak flavor windows.

Espresso extraction may appear simple, but in reality it involves the coordinated interplay of multiple variables such as dose, ratio, time, flow rate, pressure, and water temperature. This article systematically sorts through internationally accepted technical standards and Front Street's practical understanding of output parameters, analyzing each extraction factor that affects espresso flavor one by one, helping readers judge possible problems and adjustment directions when the flow rate is too fast or too slow. It also introduces in detail several espresso blend coffee beans and SOE products currently sold by Front Street, including formulation concepts, flavor characteristics, and suitable scenarios, and provides practical advice on roast dates and peak flavor periods for daily coffee bean purchases.

You may raise such questions: What exactly does a double Espresso mean? How many milliliters does the standard espresso served by a café usually have? What are the complete steps for making espresso? And how should you drink it to get the best experience?

Perhaps you also want to know: Where can you buy reliable-quality espresso blend coffee beans? From which channels do cafés usually purchase the espresso blend beans they use daily? Is there an espresso blend coffee bean brand worth recommending that supports both retail and wholesale?

Front Street Espresso Preparation Method

According to internationally accepted technical standards: weigh about 7 grams of freshly ground coffee powder, extract with hot water at about 92 degrees Celsius under about 9Bar pressure for 20 to 30 seconds, and finally obtain 20 to 30 milliliters of coffee liquid. The surface of this cup of coffee should be covered with a layer of coffee crema.

With the advancement of coffee specialization, new coffee theories are constantly being discovered; independent cafés are blooming everywhere, and the espresso extraction schemes they each adopt have also become diverse.

As for Front Street's standard output of espresso, one espresso is based on 2 shots (1 portion of espresso), using 19g of coffee powder, extracting 38g of espresso liquid at a ratio of 1:2, with extraction time controlled at 28 seconds.

However, these data are only for reference. How many milliliters should one espresso extract to be considered qualified? Front Street believes that the key is still to look at the coffee-to-water ratio and the final coffee flavor performance.

Front Street baristas often exchange insights and experiences about making coffee with everyone. I believe everyone is clear that there are many factors affecting the flavor of a cup of coffee, including ratio, water temperature, grind size, extraction time, and so on. Today Front Street will share these one by one.

How to understand espresso extraction parameters?

【Dose】 The amount of dose depends on the capacity of the filter basket.

It is not recommended to use a dose much smaller than the basket capacity, nor is it recommended to use a dose much larger than the basket capacity;

The amount of dose directly affects the density of the coffee puck. Under the same tamping force, too little coffee powder will be loose and cause the flow rate to be too fast, resulting in under-extraction; conversely, if the density is too high, the flow rate will slow down, and the coffee liquid will be difficult to extract smoothly.

【Ratio】 Refers to the ratio between the amount of coffee powder and the amount of coffee liquid. There are two factors affecting the ratio: dose and water amount.

Usually the ratio is between 1:1.5 and 1:2.5. The more common one is 1:2, for example, extracting 34g of coffee liquid from 17g of coffee powder. If the ratio is too low, the coffee will taste too strong and heavy, and it is easy to produce bitterness caused by over-extraction; if the ratio is too high, the taste will be bland and insipid, accompanied by sharp acidity caused by under-extraction.

【Time】 Refers to the time elapsed from pressing the extraction button to the end of extraction. Factors affecting extraction time include two: grind size and ratio.

The ratio is relatively easy to understand. The higher the ratio, the more water is needed for extraction, and the time will naturally be longer; grind size determines the coarseness or fineness of the coffee powder, and the degree of coarseness or fineness directly affects the density of the coffee puck. The finer the coffee powder, the denser the puck after tamping, making it difficult for water to pass through, so the time will be prolonged, and it is easy to cause over-extraction. 【Flow Rate】 Refers to the speed at which the coffee liquid flows out. The ultimate goal of adjusting extraction parameters actually all points to the result of flow rate.

Espresso needs to drip its first drop of coffee liquid at the 5th to 6th second after pressing the extraction button. If extraction is even, using 20g of coffee powder to extract 40ml of coffee liquid, and the time happens to fall at 30 seconds, it means the flow rate is normal; if the time is shorter than 25 seconds, it means the flow rate is too fast. When the coffee tastes sharply sour and lacks aroma, it is very likely under-extracted.

If the time exceeds 35 seconds, it means the flow rate is too slow, and the possibility of over-extraction increases. At this time, you can adjust by reducing the amount of coffee powder or making the grind coarser.

【Pressure】 Maintained on average at around 9bar, determined by the performance of the coffee machine. Insufficient pressure leads to low extraction efficiency, while excessive pressure easily causes over-extraction.

【Water Temperature】 Usually controlled between 90 and 94 degrees Celsius. If the water temperature is too high, over-extraction is likely, and the coffee tastes bitter; if the water temperature is too low, under-extraction is likely, resulting in sharp acidity in the coffee.

Detailed Introduction to Front Street Espresso Blend Coffee Beans (Including Specific Recipes)

As is well known, the espresso blend coffee beans used by coffee shops are made by mixing coffee beans from multiple different origins. So what exactly is the purpose of making espresso blend coffee beans? The several espresso coffee beans currently sold by Front Street cover two types: blends and SOE.

【Espresso Moka Pot Coffee Beans Recommended by Many Baristas - Front Street Dark Cocoa Blend Coffee Beans】

Flavor: Cream, Nuts, Chocolate

Front Street's basic coffee beans have extremely high cost performance. They use balanced-tasting Brazilian coffee beans as the base, then add Yunnan small-bean coffee, which is weaker in flavor and mouthfeel than Brazilian beans, to blend. It presents a taste and flavor closest to the general public, and whether you are a beginner just getting into coffee or a seasoned coffee lover, you can easily accept this espresso coffee bean.

For this blend, Front Street uses a medium-dark roast. When making espresso, the taste has slight acidity and fresh sweetness, accompanied by nutty sweetness in the aftertaste, and the overall feeling is balanced and not too harsh. The crema is at a medium level, able to meet the daily needs of most stores for making latte coffee.

Café store operations cannot do without cost considerations. While keeping costs as low as possible, providing stable coffee output is the expectation of every operator. Front Street · Espresso Moka Pot Coffee Beans Recommended by Many Baristas - Front Street Dark Cocoa Blend is an espresso bean that can meet the needs of merchants opening coffee shops.

【Front Street Specialty Blend Espresso Coffee Beans】 Flavor: Mellow, Nuts, Strong sweetness when paired with milk

For guests who do not like flavors that are too one-sided, do not particularly favor single-origin coffee, but pursue coffee quality, this specialty espresso coffee bean will be the first choice. For this blend, Front Street uses a medium-dark roast. With balanced-tasting Brazilian coffee beans as the main body, paired with Colombian coffee beans that have soft fruity acidity and nutty sweetness in the aftertaste, the flavor is classic.

This blend is also the blend we have been using in our own store. It has been used since about half a year after opening the store and continues to this day. When discussing this blend, we hope to use American beans as the main body to enhance the nutty and sweet mouthfeel of the blend and minimize the appearance of overly bitter flavors.

【Front Street Commercial Blend Espresso Coffee Beans】

Flavor: Mellow, Nuts, Strong sweetness when paired with milk

This blend tastes rich in crema and mouthfeel, as well as caramel sweetness, and also carries flavors of nuts, cocoa, and dark chocolate. The acidity and sweetness are balanced, with a slight hint of sweetness and bitterness, and a lasting finish. A small amount of Robusta coffee beans is added to increase the richness of the crema, and because the amount used is small, it will not change the flavor too much.

The reason Front Street named this blend "Commercial Blend Coffee Beans" is that it performs excellently whether making Americano or milk coffee, and combined with its price advantage, it is very suitable for commercial cafés. The espresso crema is very rich, the taste is smooth with slight bitterness, and the texture is extremely full-bodied.

【Front Street · Strawberry Candy Espresso Blend Coffee Beans】 Flavor: Rose, Grape, Candied Fruit, Blueberry, Fruit Gummy

To make espresso with fruity notes, medium-roast coffee beans should be the main choice. Front Street Strawberry Candy espresso coffee beans are recommended and can be ordered directly from the Taobao or Tmall store. This is based on two major origins: Front Street Costa Rica Tarrazu, famous for its honey processing, and Ethiopia, the birthplace of coffee, plus Colombian coffee beans. The espresso blended in this way is not only not harsh, but also has good crema and a dense texture under coffee machine extraction, while presenting a sweet-and-sour taste like strawberry gummy.

Front Street Coffee (FrontStreet Coffee) stores adjust parameters every day according to the condition of the beans, for example, using 20 grams of coffee powder to extract 40 grams of coffee liquid. Extraction time will be controlled between 26 and 28 seconds. The espresso made with these parameters has medium acidity, medium bitterness, and medium body, with good balance. The flavor is obvious dark cocoa and citrus, and the finish is fermented wine aroma. When made into Americano, it shows obvious winey chocolate and citrus acidity; when made into latte, it presents flavors such as vanilla cream and liqueur chocolate.

Front Street reminds everyone of several precautions when buying coffee beans daily Roast (Production) Date: When buying coffee beans, pay attention to checking the roast date. Front Street coffee beans generally have the roast date printed on the back of the bag.

Drink Within the Peak Flavor Period: The peak flavor period of freshly roasted coffee beans is within 30 days after the resting period (4-7 days). After that, the flavor will be lost over time, and eventually only a woody taste will remain. The flavor substances lost first are mainly volatile compounds such as floral and fruity aromas, while water-soluble compounds such as sugars, nuts, and chocolate are relatively less volatile.

Therefore, we usually remind customers buying beans that the best peak flavor period for coffee is within the 4th to 30th day after the roast date. However, even if the peak flavor period has passed, it does not mean this coffee cannot be drunk. It will just perform slightly less well in terms of flavor.

It should be emphasized here that there is a difference between the peak flavor period and the shelf life. Generally, the shelf life of roasted coffee beans is maintained between 6 months and 12 months. Therefore, when buying roasted coffee beans, it is not that the fresher the better, and at the same time remember not to store them too long before remembering to drink them. When buying coffee beans, please pay attention to the roast date to ensure that you can finish drinking them within a fixed period of time and avoid waste.

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