Introduction to the Two Main Goals of Espresso Coffee Blends and How to Adjust Flavor Profiles

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Understanding Espresso

Espresso is a beverage created by forcing near-boiling high-pressure water through finely ground coffee. Espresso is generally thicker than coffee brewed by other methods, containing higher concentrations of suspended and dissolved solids, such as the crema on the surface (a creamy-textured foam). Due to its pressurized brewing process, espresso has an intense flavor with extremely high concentrations of chemical compounds. It's often used as the base for other drinks like latte, cappuccino, macchiato, mocha, and Americano.

Beneath the foam, espresso contains particles with emulsified microscopic oil droplets, dissolved sugars, acids, protein-like substances, and caffeine. Moreover, espresso has always held a very high status in the hearts of coffee enthusiasts, not only because of its rich taste and pure Italian heritage but also as a solution with suspended bubbles and solids. Due to constantly changing humidity and storage times, and the wear of grinder blades changing over time, we adjust the grinding degree daily to ensure consistent espresso flavor. So how can we make a perfect espresso?

Understanding Coffee Blends

Blended coffee, also known as coffee blending, involves mixing various single-origin coffee beans to fully leverage the strengths of each variety. Blended beans are created by mixing coffee beans from different origins to achieve a more balanced flavor profile. For example, if one coffee bean is smooth but lacks aroma, another bean rich in fragrance can be added to complement each other's strengths, creating a coffee with either complementary or enhanced flavors, thus producing a richer new taste experience. Sometimes beans are mixed first and then roasted - this is called raw blending; sometimes beans are roasted separately and then mixed - this is called post-roast blending.

ESPRESSO Formula

The ideal Italian-style espresso has very low acidity, high body, and rich, velvety, thick reddish-brown crema containing the coffee's aroma and flavor. Crema is the single most important indicator of a complete espresso - it must capture the coffee's intense flavors. The steam produced during espresso extraction is contained in fine oil foam, and when drinking espresso, these foam bubbles explosively release volatile aromatic molecules that travel from the mouth to the nasal olfactory receptors. This foam also adheres to the taste buds, creating a lingering aftertaste that can last up to an hour.

Some people prefer to use single-origin coffee for SOE (Single-Origin Espresso), which might be the simplest approach, but I believe the results require compromise. Because no single-origin coffee provides all the physical and flavor characteristics in the right balance, high-quality espresso must combine two or more coffees.

Simply put, I believe espresso characteristics can be described from two broad and different directions. Physical characteristics: such as color, thickness, crema; Flavor characteristics: such as aroma, taste, and aftertaste. Physical characteristics come from one group of coffees, while flavor characteristics come from another group. Although these two characteristics aren't truly separable, I must make choices so that coffees providing thick texture for espresso's color, thickness, and crema have less performance in aroma and taste, and vice versa. In practical situations, the variables of these two characteristic groups can be adjusted independently.

Natural-processed coffees often have more crema than washed coffees. If you can find a natural-processed coffee with low acidity and high body, it will be an excellent base for espresso. Asian coffees, especially those from India and Indonesia, plus Brazilian coffees, offer low-acidity options. After selecting the base bean, we must evaluate whether this formula is suitable for adding high-quality Robusta. High-quality Robusta is difficult to obtain and expensive, often more expensive than many Arabica beans. However, espresso can use clean-textured, mild specialty Robusta.

Unlike general grades, higher-priced Robusta can create smoother, milder, softer mouthfeel without rubbery aftertaste. Additionally, it increases the caffeine content in espresso, which is an extra benefit that many people seek. The Robusta content in espresso blends varies depending on the bean's aging degree, grade, and roast level. But more importantly, it depends on the other coffee components. Considering that most espresso-based beverages sold in North America are milk drinks, high-quality Robusta is an effective way to help enhance coffee acceptance. Through fusion with milk, Robusta can help Arabica enhance flavors.

Perhaps the most significant impact of quality Robusta is its ability to increase crema richness and persistence without affecting the most important moderate quality of high-quality espresso. It also adds unique flavors to the taste profile, typical European-style espresso flavors that I believe Arabica cannot achieve alone.

To add flavor components to the formula, choose one or two coffees whose aroma and taste you truly enjoy. I call them "focal coffees." These coffees can have medium or lower body, even with some acidity. Start with one coffee, and if necessary, add a second coffee flavor.

The next step is to balance this formula. All characteristics must blend together without any particular one overpowering the others. It must be smooth, mild, thick, without uncomfortable bitterness, and without noticeable acidity. The crema should be rich, smooth, velvety, and not easily dissipating. Pay special attention to the aftertaste - the aroma must be very pleasant, so when the oil foam bursts, steam fills the nasal receptors, creating a pleasant experience.

Pre-roast vs Post-roast Blending

Whether pre-mixing raw beans or mixing after individual roasting depends on the characteristics of the coffees in the formula. Both methods are acceptable. Post-roast blending allows different roast degrees for each bean so that each component performs at its best. It also provides opportunities for non-home roasters to create their exclusive formulas. The most obvious disadvantage of this method is that if the roastery is concerned about freshness, it requires multiple roasts, causing waste.

When the roasting characteristics of coffees in the formula are compatible, pre-roast pre-mixing can be feasible. However, when the beans have different bean sizes, densities, moisture content, thermal conductivity, and roast development curves, pre-mixed roasting becomes difficult and impossible in most situations.

FrontStreet Coffee Premium Espresso Blend

Coffee Beans: Colombia : Brazil, ratio 3:7

Colombia Huila Region

Located in southwestern Colombia, it's one of the main coffee cultivation areas. Colombian coffee generally grows at altitudes of 1500-1800 meters, mostly Bourbon and Caturra varieties, processed using the washed method. It has high density, uniform bean size, and plump beans (thicker from bean core to surface). Because the Huila region is scattered with famous coffee cultivation areas, the names of various small areas have become brand names and circulated. Although the cultivation conditions in this region are also very good, the coffee cultivation farms and surrounding cultivation infrastructure are not well developed. Raw bean drying equipment or washed processing facilities are not yet complete, which is truly regrettable. Coffee from the Huila region has strong flavor and heavier texture.

In particular, the nutty, chocolate, and caramel aromas and suitable acidity of Huila region coffee are worthy of being called high-end specialty coffee. The nutty, chocolate, and caramel aromas and suitable acidity are worthy of being called high-end specialty coffee.

Flavor Profile: Rich and solid mouthfeel with pleasant acidity, fragrant aroma, moderate acidity, and rich sweetness that is intriguing. Due to its affordable price and small beans, it's suitable for blending coffee. The coffee has strong flavor and heavier texture. Its nutty, chocolate, and caramel aromas and suitable acidity are worthy of being called high-end specialty coffee, suitable for single-origin or espresso blend base.

Brazil Cerrado Region

Brazilian coffee generally grows at altitudes of 1000-1300 meters, so its density is relatively low. Mostly Bourbon varieties, processed using semi-natural method. Moderate moisture content, softer bean texture, and thinner thickness from bean surface to core, so it's not suitable for high-temperature roasting, as the temperature of the roasting chamber wall can burn the bean surface, creating bitter burnt flavors.

At the same time, to express the characteristics of nuts, milk chocolate, and good body, and as a blend base, we use a medium-heat bean-charging approach, maintaining heat until the dehydration stage, then making fine adjustments as temperature rises after first crack begins, promoting more complete caramelization reactions, and discharging beans when approaching second crack.

Flavor Profile: Comfortable sweet-bitter taste, extremely smooth entry; with light grass aroma, fresh fragrance with slight bitterness; sweet and smooth, with a refreshing aftertaste;

Blended Flavor: Sweet and fragrant mouthfeel. Using medium-dark roast, when making espresso, the taste will have soft, slight acidity, clear sweetness, nutty aftertaste, with an overall feeling that isn't too stimulating, balanced, with moderate crema, suitable for daily beverage production needs in coffee shops.

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