Espresso | The Foundation of Italian Coffee, How is Espresso Really Made?

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Single Origin vs. Espresso Coffee

Today, when you walk into a specialty coffee shop and browse through the coffee options, it's not difficult to find two main categories - single origin coffee and espresso coffee.

How exactly is espresso base made?

Today, I'd like to share my experience with everyone.

Factors Affecting Espresso Flavor

First, we should know what factors affect espresso flavor:

(1) Water Pressure

Modern espresso machines use a water pump to control water output and adjustable water pressure. The ideal water pressure for espresso is generally 9 BAR, which is widely recognized as the most ideal pressure.

(2) Boiler Pressure

Boiler pressure affects the water temperature for making coffee and the force of steam. The higher the boiler pressure, the higher the water temperature and the greater the steam force; conversely, the water temperature is lower and the steam becomes weaker. Boiler pressure is generally around 1 BAR, although this value is still controversial today, and each barista has their own understanding.

(3) Water Temperature

Water temperature needs to be determined according to the requirements of different coffee bean varieties. Some are constrained by boiler pressure, while others allow for flexible precise settings. According to most baristas' experience, water temperature between 90-92°C is suitable. Each barista can make flexible adjustments based on their understanding and needs, creating their own style of espresso through their hands.

(4) Tamping Pressure

Tamping comes in various styles, and it's rare for two people to have exactly the same tamping technique. Generally, for heavy tamping, the required pressure would be around 25kg/m², but tamping is indeed the most flexible parameter among the golden rules. Because we use a constant pressure tamper, the tamping force is basically consistent.

(5) Coffee Bean Grind Size

Espresso uses extremely fine grounds. The finer the grind, the slower the water flow through the coffee layer; the coarser the grind, the faster the water flow through the coffee layer. Adjusting the grind size can change extraction time while achieving the desired extraction amount. Consider this scenario: using a fixed 20g of coffee grounds to extract 40g of espresso, taking 25 seconds. Everything looks perfect, but when you taste it, the body is thin and sharp in acidity. Obviously, this espresso is under-extracted and low in concentration. At this point, grinding the coffee beans finer can solve the problems of under-extraction and low concentration while reducing sharp acidity and increasing richness.

(6) Dose Amount

For our single shot espresso, we use 12-14g of coffee grounds, and for a double shot, it's 20-22g.

(7) Extraction Time

The golden rule specifies extraction time between 25-28 seconds, but extraction time is actually a comprehensive expression of tamping, dose amount, and grind size, requiring adjustment based on the barista's understanding.

(8) Extraction Yield

For single extraction, we extract 20-21g of liquid, and for double extraction, we extract 40g of liquid. Except for a few Italians who might use single dose amounts but only extract 15ml of coffee liquid.

(9) Crema

The complexity of crema cannot be explained in just a few words. Simply put, a good espresso needs to have rich, golden-brown crema.

Professional Tips:

(1) We use the Fiorenzato 900N espresso grinder and Faema E78 espresso machine, using a tamper. Water pressure, boiler pressure, and water temperature remain basically unchanged. Basically, we add new beans daily, shake the bean hopper evenly, grind out old beans from the burrs, and use fresh coffee grounds to clean any residual old powder inside.

(2) We've determined our technique for receiving and distributing grounds. For blend beans, we use Colombia and Brazil in a 4:6 ratio. The overall flavor is sweet and fragrant, with mild non-irritating acidity, balanced sweet and sour, and medium crema.

An ideal espresso should achieve balance among all elements, with distinct flavor characteristics, leaving a sweet aftertaste in the throat without bitterness. More specifically, it should have moderate acidity, bitterness, and sweetness, rich flavors, solid and concentrated thickness, with a lasting aftertaste that feels refreshingly acidic like citrus.

Double dose: 22g, extracting 40g liquid, time: 27 seconds

Espresso Blends

Blend beans are mostly used for espresso coffees such as Espresso, Americano, Latte, or Cappuccino. The coffee flavor is more balanced, smoother, and more stable, making it more appealing to the general public.

Blended coffee, also known as mixed coffee, combines various single-origin coffee beans to fully utilize the strengths of each individual bean. Blend beans are made from coffee beans of different origins to create a more balanced flavor profile.

For example, if one coffee bean is smooth but lacks aroma, another bean rich in aroma can be added. The advantages of individual coffee beans complement each other, either compensating for or enhancing flavors, thereby creating a richer new taste experience. Sometimes beans are mixed first and then roasted - this is called green blending; sometimes coffee beans are blended after roasting - this is called roasted blending.

Post-roast blending allows different degrees of roasting for each bean, so that each component performs at its best.

Before blending beans, one must first understand the different flavors of coffee varieties from around the world, as beans have different characteristics depending on their origin. Different coffee beans have distinct personalities due to different varieties and origins, with subtle differences in acidity, bitterness, sweetness, aroma, and body. Single-origin coffee beans often focus more on expressing the unique characteristics of a particular coffee type.

The Rise of Single Origin Espresso (SOE)

SOE has become popular recently. SOE stands for Single Origin Espresso. Although not necessarily equivalent to specialty coffee, if you select single-origin coffee beans with easily identifiable flavors as SOE, you can create espresso with unique and typical flavors. For example, the typical citrus flavor of Yirgacheffe or the fruity notes of Kenya, plus espresso amplifies the coffee's flavor, so specific flavors become more prominent compared to pour-over. However, although SOE shows outstanding characteristics, because it comes from a single origin, its defects are also relatively easily amplified. Factors like roasting and grind size all affect the flavor, so it's not necessarily better tasting than blended coffee.

Robusta

Mainly used in espresso blends to increase body and obtain rich crema. Robusta coffee beans are oval, spherical, or near-spherical in shape, with a straight center line.

Arabica

Arabica coffee produced in different regions, altitudes, and climates has its own characteristics, showing completely different personality flavors. When unroasted, it smells like fresh grass. After proper roasting, it reveals "fruitiness" (light to medium roast) and "caramel flavors" (dark roast). Suitable for single origins and various blends, and can be made using various extraction techniques.

◎ Arabica coffee beans are long-oval and flat in shape, with an S-shaped or C-shaped center line.

How Much Robusta is Suitable for Espresso Blends?

For the blend beans typically used by independent cafes, we believe 10% Robusta, or within 20% is suitable. Beyond this proportion, there tends to be a rubbery taste.

How Do We Blend?

(1) FrontStreet Coffee Espresso Blend No. 2: Colombia: Brazil, ratio 3:7, 100% Arabica. Flavor characteristics: comfortable bitter-sweet taste, extremely smooth entry; with a light grassy fragrance, fresh aroma with slight bitterness; sweet and smooth, with a pleasant aftertaste; using medium-dark roast, when making espresso, it has soft, mild acidity, sweet, nutty aftertaste. The overall feeling is not too stimulating, balanced, with medium crema.

(2) Commercial Blend:

Colombia: Brazil: Robusta; ratio 3:6:1, green blend;

In terms of individual bean flavors, commercial coffee beans are much inferior in taste to specialty coffee beans. Generally, commercial beans are chosen for blending. After blending, they can also produce coffee with excellent taste, suitable for making lattes, cappuccinos, and other espresso coffees. When we use our commercial blend for espresso, because of the Robusta beans, the crema is richer, the flavor is classic, with caramel sweetness, nutty and cocoa-like, dark chocolate flavors, balanced sweet and sour, with a slight bitter taste, and a lasting aftertaste.

(3) Basic Blend:

Yunnan AA: Brazil; ratio 3:7, roasted blend; with soft fruit acidity, caramel sweetness, nutty and dark chocolate flavors, smooth and thick, but with a relatively light taste.

Actually, adding Robusta beans to some espresso recipes can bring more caffeine, better crema, and flavor balance. Commercial blends with Robusta beans and the 100% Arabica "Specialty Espresso #2" actually contain less than 10%. If you're making milk coffee, you basically can't taste it, but the overall crema of the coffee will be significantly improved~~

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473