Why Does Espresso Rely on Blend Coffee?

Espresso beans are usually roasted darker, often taken past second crack, because the shot is later mixed with milk, cream, or water and needs enough strength and bitterness to hold up. They are also mostly blends, chosen for stability and cost rather than any rule that singles cannot be used.

Robusta coffee beans typically make up 10% to 20% of an espresso blend, adding body and crema. Four Front Street blends are profiled by ratio and flavor. Extraction then turns on eight variables: water pressure, boiler pressure, temperature, tamping force, grind size, dose, time, and extraction yield.

To make a stable Espresso or a smooth milk coffee, choosing the right beans is only the starting point. Why are espresso beans mostly dark-roasted and primarily blends? Now that single-origin SOE has risen, how should one weigh the trade-offs? Drawing on Front Street Coffee's production experience, this article sorts out the two bean-type combinations for espresso blends, the suitable proportion of Robusta beans (within 10%-20%), and introduces one by one the ratios and flavors of four Front Street espresso blend beans. The latter part focuses on the extraction stage, analyzing the eight major variables of water pressure, boiler pressure, water temperature, tamping force, grind size, dose, time, and extraction yield, and provides Front Street's espresso base production process and dose-to-yield ratio reference, helping enthusiasts find their own cup between balance and personality.

So-called espresso beans refer to the type of beans specifically used to make espresso. What exactly is the difference between them and other coffee beans seen in daily life? Front Street breaks it down from several key dimensions.

The first is roast depth. Taking café production as an example, if following the drip (pour-over) route, beans on the lighter roast side are usually chosen, with the aim of bringing out floral and fruity notes. Beans for espresso production, however, often must wait until after second crack before being dropped, meaning the overall roast is on the darker side. The reason is that espresso will subsequently be mixed with milk, cream, or water, so the flavor must be strong and bitter enough to hold up.

The second is single-origin versus blend. Espresso beans are still mainly blends, which contrasts with single-origin coffee beans. It should be noted that blend beans are not necessarily espresso beans, and single-origin beans can also be used to make espresso. Espresso beans lean toward blends mainly out of consideration for stability and cost.

What coffee beans are suitable for making espresso?

Front Street Coffee (FrontStreet Coffee) reminds you of one point: before mixing beans by hand, you must first understand the flavor tendencies of different coffee varieties around the world. Beans have their own characteristics according to origin, and roasters need a relatively clear comparison of the characteristics of coffee beans from multiple regions in order to adjust the roasting curve accordingly. Different coffee beans have different personalities due to variety and origin, with subtle differences in acidity, bitterness, sweetness, aroma, body, and other flavors, and single-origin coffee beans often focus more on expressing the unique characteristics of a certain type of coffee.

The single-origin SOE trend

In recent years SOE has become quite popular, representing single-origin espresso. Although it is not necessarily equivalent to specialty coffee, if you choose single-origin beans with easily recognizable flavors to make SOE, you can produce an espresso with a unique and typical flavor. For example, the typical citrus note of Front Street Yirgacheffe and the fruity note of Front Street Kenya, combined with the espresso method that amplifies the coffee's flavor, make specific flavors more prominent than in pour-over. However, although SOE performs brilliantly, since it comes from a single origin, its shortcomings are also relatively easy to magnify, and factors such as roasting and particle size will affect the flavor, so it is not necessarily tastier than blended coffee.

How does Front Street choose espresso blends? What coffee beans are suitable for making espresso? Espresso beans generally use two types of beans—Robusta and Arabica—and the blending method is usually Robusta blended with Arabica, or Arabica blended with Arabica.

[Robusta]

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

[Arabica]

Arabica coffee produced in origins with different regions, different altitudes, and different climates each has its own characteristics and can display distinctly different personality flavors. When unroasted, it smells fresh and grassy; after proper roasting, it displays "fruity notes" (medium-light roast) and "caramel flavor" (dark roast), and is 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 to add to espresso blend beans]

Front Street Coffee (FrontStreet Coffee) believes that espresso beans containing within 10%-20% Robusta are more suitable; exceeding this ratio gives a rubbery taste.

Front Street Coffee (FrontStreet Coffee) currently produces four Front Street espresso blend coffee beans with different flavors, meeting the taste needs of most people.

(1) Front Street Specialty Espresso Blend Coffee Beans: Colombia coffee beans : Brazil coffee beans, ratio 3:7, 100% Arabica

Flavor characteristics: comfortable sweet-bitterness, extremely smooth on entry; with a faint grassy aroma, light fragrance with slight bitterness; sweet and smooth, with a pleasant finish; using a medium-dark roast, when making espresso the mouthfeel has a soft slight acidity, clean sweetness, and nutty sweet aftertaste, and the overall impression is not too stimulating, peaceful, with medium crema—an espresso blend bean that meets the daily production needs of coffee shops.

(2) Front Street Commercial Espresso Blend Coffee Beans: Colombia coffee beans : Brazil coffee beans : Robusta coffee beans, ratio 3:6:1

In terms of the flavor of the individual beans, the coffee obtained from commercial beans is much inferior in taste to that from specialty coffee beans. Generally, commercial beans are chosen for use as espresso blend coffee beans, and through blending they can also produce quite good-tasting coffee, usable for making lattes, cappuccinos, and other espresso drinks. When Front Street Coffee (FrontStreet Coffee) uses this Front Street commercial blend espresso coffee bean to make Espresso, because of the Robusta beans, the crema is a bit richer, the taste is classic, and it suits daily shop needs.

Flavor characteristics: caramel sweetness, nutty and cocoa-type, dark chocolate flavors, balanced acidity and sweetness, slightly sweet-bitter, with a lasting finish.

(3) Front Street Dark Cocoa Blend Coffee Beans: Yunnan coffee beans : Brazil coffee beans, ratio 3:7

Flavor characteristics: with soft fruit acidity, caramel sweetness, nutty and dark chocolate flavors, smooth and viscous, but relatively light in taste. This cost-effective coffee bean is suitable for shops and home users who prioritize cost and have average requirements for flavor.

(4) Front Street Sunflower Warm Sun Espresso Blend Coffee Beans: Front Street Honduras Sherry coffee beans : Front Street Yirga Red Cherry coffee beans, ratio 7:3

Flavor characteristics: obvious fruit acidity, a faint berry aroma lingering, rich wine aroma and chocolate flavor, and a comfortable sweet aftertaste.

In fact, Front Street Coffee (FrontStreet Coffee) has found that adding [Robusta beans] to an espresso recipe can bring more caffeine and produce better crema and richness.

What factors affect espresso extraction?

(1) Water pressure

In modern machines, a water pump controls the water output and the controllable water pressure. The ideal water pressure for Espresso is generally 9 BAR, which is also the most ideal pressure universally recognized.

(2) Boiler pressure

Boiler pressure is related to the water temperature for making coffee and the strength of the steam. The higher the boiler pressure, the higher the water temperature and the greater the steam force; conversely, the lower the water temperature and the weaker the steam. Boiler pressure is generally around 1 BAR, though of course this value still remains quite controversial, and every barista understands it differently.

(3) Water temperature

Water temperature needs to be determined according to the variety requirements of different coffee beans; some are constrained by boiler pressure, while others can be set more flexibly and precisely. According to most baristas' experience, the water temperature is between 90 and 92 degrees Celsius, and each barista can flexibly adjust it according to their own understanding and needs, and can use their own hands to make an Espresso in their own style.

(4) Tamping force

There are various styles of tamping, and in this world almost no two people tamp exactly the same. Generally speaking, if it is a heavy tamp, the required pressure would be something like 25kg/m2, but tamping is indeed the most free parameter among the golden rules. Because Front Street Coffee (FrontStreet Coffee) uses a calibrated tamper, the tamping force is basically consistent.

(5) Espresso bean grind size

Espresso is an extremely fine grind. The finer the grind, the slower the water flows through the coffee bed; the coarser the grind, the faster the water flows through the coffee bed. Adjusting the grind size allows you to flexibly change the extraction time while reaching the extraction yield. Imagine this situation: using a fixed dose of 20g to extract 40g of Espresso, taking 25 seconds. Everything looks perfect, but upon tasting you find the body is very thin and sharply sour. Clearly, 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 overly low concentration while reducing the sharp acidity and increasing body.

(6) Dose

Front Street Coffee (FrontStreet Coffee) uses 12-14 grams of coffee grounds for a single espresso and 20-22 grams for a double.

(7) Extraction time

The golden rule sets extraction time between 25-28 seconds, but extraction time is actually the combined expression of tamping, dose, and grind size, and needs to be adjusted by the barista's understanding.

(8) Extraction yield

Front Street Coffee (FrontStreet Coffee) extracts 20-21g of liquid for a single shot and 40g of liquid for a double shot. Combined with the dose, this is the key to the espresso extraction dose-to-yield ratio.

How does Front Street make the espresso base?

First wipe the portafilter dry, then add 20g of coffee grounds into the coffee basket, then use a distribution tool to level the coffee grounds, and then use a tamper to press the coffee puck tight. Lock the portafilter onto the group head, start the extraction button (for a lever type, pull the lever), and stop extraction when the coffee liquid reaches 40g. The extraction time is between 28-32 seconds.

An ideal cup of Espresso should achieve a balance among all elements, with a vivid mouthfeel, and after drinking, the throat should feel sweet and mellow rather than bitter. To put it more specifically, it should have moderate acidity, bitterness, and sweetness, rich flavor, solid and full-bodied viscosity, and a lingering finish, giving a refreshing citrus-like acidic aftertaste.

Blend beans are mostly used for espresso drinks such as Espresso, Americano, Latte, or Cappuccino, etc. The coffee's taste is more balanced and smoother, and the flavor is also more stable, which can be said to be more popular in taste.

For professional coffee knowledge exchange and more coffee bean information, please follow Coffee Workshop (WeChat public account cafe_style) For more specialty coffee beans, please add the private WeChat Front Street Coffee (FrontStreet Coffee), WeChat ID: kaixinguoguo0925

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