The Arabica coffee bean is more elongated and generally has a larger caliber (technically called screen size) compared to Robusta. Additionally, the Arabica bean features a more pronounced characteristic central "S" shaped groove.

Published on 11 November 2024 on The history of coffee
by Fabio Arangio

Arabica and Robusta: the two souls of Italian coffee

Coffee is much more than just a beverage in Italy; it is a true culture, a daily ritual that unites generations and traditions. Italian-style coffee has become a trend abroad, certainly also thanks to the use of capsules, which has made it easier to make an espresso at home.

Behind every cup lies an art that begins with the selection of the beans. Two main varieties dominate the coffee landscape: Arabica and Robusta. The right blend of these two types of coffee is what gives balance and character to our espresso cups, revealing flavor nuances that can satisfy even the most demanding palates.

The Coffee Plant and Green Bean

The coffee plant, belonging to the Coffea genus, grows in the tropical areas of the world and requires specific climatic conditions to produce high-quality fruit. The process that transforms these fruits into our beloved coffee beans starts with the harvesting of the cherries, followed by careful processing.
The beans are separated from the pulp and dried until they reach the state of green bean, ready for the roasting process that, with care and skill, we transform into a product with an unmistakable aroma and fragrance.

Green coffee in the characteristic jute sacks in our company. - @ Il Caffè Manaresi

Arabica and Robusta differ not only in taste but also in their physical and chemical characteristics.

Arabica

Arabica (Coffea arabica) accounts for about 60-70% of the world’s coffee production and is known for its sweet and delicate flavor, with complex aromatic notes ranging from dried fruit to chocolate.
Arabica plants are more demanding in terms of climate and altitude and are mainly cultivated in Latin America (Brazil, Colombia, Costa Rica), Ethiopia, and certain areas of Asia.

Arabica beans contain less caffeine than Robusta, but they are appreciated for their pleasant acidity and light body, which provide a refined and aromatic tasting experience.

Appearance and Chemical Characteristics of Arabica Coffee Beans

Arabica beans are generally larger, oval and elongated in shape, with a slightly wavy central groove.
The caffeine content is lower than Robusta, usually between 1% and 1.5%, while it has a higher concentration of lipids and sugars (about 60% more than Robusta), which contributes to its aromatic complexity and sweet taste.
Chemically, Arabica contains lower levels of chlorogenic acid compared to Robusta, making it less bitter and astringent.

Robusta

Robusta (Coffea canephora) makes up the remaining 30-40% of world coffee production and is characterized by a stronger, fuller taste with notes of dark chocolate and a hint of bitterness.
The Robusta plant is more resilient – hence the name – and grows at lower altitudes, mainly in Africa (Uganda and Ivory Coast) and Asia (Vietnam and India).

Robusta beans are rich in caffeine, offering a coffee with a strong flavor and dense crema, perfect for those who prefer a stronger, more structured beverage.

Appearance and Chemical Characteristics of Robusta Coffee Beans

Robusta beans are smaller and rounder, with a straight central groove.
They have a higher caffeine content, ranging from 2% to 2.7%, providing a more intense and persistent cup.
Robusta has fewer lipids and sugars than Arabica, resulting in a more bitter and intense flavor.
The higher concentration of chlorogenic acid in Robusta contributes to its resistance to diseases, a factor that, combined with its tolerance for lower altitudes and higher temperatures, favors its cultivation in difficult areas.

The poster in the company showing the origins of green coffee. - @ Il Caffè Manaresi

A Matter of Roasting

There are significant differences in the roasting of Arabica and Robusta, related to their chemical and organoleptic characteristics. Roasting is a process that must be adapted to the bean variety to enhance its aromatic profile without overpowering or diminishing its natural taste.

Roasting Arabica

Arabica has a delicate aromatic profile and a chemical structure that contains more sugars and lipids than Robusta. This makes Arabica ideal for light or medium roasts, which preserve its floral, fruity, and slightly acidic notes. A roast that is too dark can burn these subtle aromas, leading to unwanted bitterness and masking its natural sweetness and complexity. A medium roast, therefore, balances acidity and body, maintaining the smooth and aromatic taste that characterizes 100% Arabica coffees.

Roasting Robusta

Robusta, with its higher caffeine and chlorogenic acid content, has a naturally stronger and more bitter flavor, with earthy and woody notes. For this reason, Robusta is often roasted for a longer time and at higher temperatures, resulting in a dark roast that reduces astringency and smooths the flavor. The dark roast of Robusta develops a dense crema and intense body, characteristics that make it ideal for Italian espresso and perfect in blends. This enhances the dark chocolate notes and the bitter aftertaste, making the flavor profile more balanced.

Blended Roasts

In Arabica and Robusta blends, master roasters tend to find a balance in the roasting curves, often combining a medium roast for Arabica and a dark roast for Robusta, or roasting the varieties together with precise techniques. This allows the flavors to harmonize, bringing sweetness and body to the cup with the right intensity and persistence typical of Italian coffee.

Other Coffee Varieties

In addition to Arabica and Robusta, there are other coffee varieties, although they are less known and make up a small percentage of global production. The main ones are:

Liberica (Coffea liberica)

Native to West and Central Africa, Liberica is mainly grown in Malaysia and the Philippines. Liberica beans are larger and more irregular than Arabica and Robusta, with a complex and intense aromatic profile that can resemble smoky, fruity, and floral notes. It has low acidity but a full body and a very distinctive taste, sometimes with woody or smoky hints, which tends to polarize consumer preferences. It is often used in local blends and rarely available in international markets.

Excelsa (Coffea excelsa)

Previously considered a variety of Liberica, Excelsa has recently been recognized as a separate species. It mainly grows in Southeast Asia and accounts for less than 1% of global coffee production. Its aromatic profile is unique, with a bright acidity and medium body, often featuring intense fruity and floral notes. It is mainly used in blends to add complexity and depth.

Other Minor Varieties

There are also experimental and local coffee varieties, such as Bourbon and Typica, which are actually sub-varieties of Arabica but with distinctive characteristics. Some of these varieties are grown in specific areas and are highly regarded by connoisseurs for their uniqueness and the distinctive aromatic profiles related to the terroir and cultivation techniques.
These minor varieties, while less common, enrich the diversity of the coffee world and offer different aromatic profiles, especially appreciated in specialized tastings and niche markets.

Arabica and Robusta, a Matter of Balance

The balance between Arabica and Robusta is a choice that every roastery makes with care and skill, to create blends capable of telling a story of flavors and traditions. In our daily work as a historic Florentine roastery, we are committed to preserving and enhancing this culture, selecting the best beans to offer those who choose us an experience that is not just a pleasure but a true passion.

Single-Origin Coffees: For Tasting but Not for Everyday Consumption

In recent years, the growing attention to origin and quality has led to the spread of single-origin coffees, appreciated for their ability to highlight the unique character of a single variety or production region. Single-origin coffees allow one to perceive particular aromatic nuances, such as fruity, floral, or spicy notes, characteristic of the variety and terroir of origin. However, this pure approach also has its limits. The flavor structure of single-origin coffees often appears unbalanced, with a marked acidity and a complexity that, though fascinating, may be overwhelming for palates accustomed to traditional Italian espresso. Furthermore, their taste and olfactory profile, not balanced by the addition of Robusta, makes them less suitable for milk-based drinks such as cappuccino or caffè latte. Milk tends to accentuate the acidity of single-origin coffees, leading to a less harmonious and satisfying taste compared to blends, which are designed to achieve a perfect equilibrium.