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The Different Types of Coffee Roasts

Coffee roasting is the process where heat is applied to raw, green coffee beans to unlock their aromatic profile composed of multiple complex and tasty notes. Achieving the perfect roast involves a balance of time and temperature.

The roasting process also influences the coffee's acidity and texture to varying degrees. Understanding the characteristics of the different roast levels can elevate your coffee experience as you identify which coffee roast best suits your palate. This article will guide you through the differences between the types of coffee roasts, helping you make a more informed decision when selecting your next coffee blend.

The Impact of coffee roasting

Coffee in its unroasted form is far from the coffee we commonly associate with its consumption. Roasting coffee develops the complex tastes and aromas of the beans, and optimally adjusts acidity and bitterness levels to create an unforgettable in-cup taste.

Coffee roasting is a series of chemical reactions that create new flavour compounds and enhance existing ones. These chemical changes are influenced by several factors, such as the roast duration, temperature, and even the origin of the beans, the way they have been harvested and processed, resulting in the different types of coffee roast types.
A delicious cappuccino with a sleeve of Nespresso coffee and a sleek white Grand Lattissima machine on a table.

How Coffee Roasting Affects the Taste of Coffee

When coffee beans are roasted, a host of chemical reactions are set into motion. The key during this chain of reactions is the “Maillard reaction”, which is responsible for the colour changes of the grain, their evolution in terms of weight, volume, and density, as well as aromatic development.


The result is a distinct change in the coffee where new flavour compounds emerge, and existing ones are altered/enhanced. The darker the roast, the more intense flavours become while lighter roasts enhance more of subtle floral, fruity aromatic characteristics that result in a brighter tasting cup.
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How the “Maillard Reaction” Affects Coffee Taste

The Maillard reaction is a chemical reaction between amino acids and reducing sugars that occurs when foods are cooked or heated. Named after French chemist Louis-Camille Maillard, who first described it in 1912, this reaction is responsible for the browning and flavour development in foods such as bread, meat, and coffee beans.


In terms of coffee roasting, the Maillard reaction plays a critical role in developing the complex flavours and aromas that make coffee enjoyable. During the roasting process, the high temperatures trigger this reaction between the amino acids and sugars in the coffee beans. The result is the formation of various compounds that contribute to the characteristic flavours we associate with coffee, such as nutty, caramel, and chocolate notes.
A woman sits on a couch with her laptop and a coffee on her journal to avoid stains, with a Nespresso machine in the background.

The Coffee Roasting Process

Coffee roasting is a complex process, often divided into multiple stages, each contributing to the bean's final taste, texture, and aroma.

Split Roasting Coffee Beans

Split roasting is a specialized method of roasting, that involves roasting different types of coffee beans separately under specific temperature and time conditions. The split does not necessarily have to be done by variety, you can blend two varieties (10 kg + 10 kg) lend them, and still use two roasters to roast 5 kg in one and 145 kg in one.

This technique allows each bean variety to reach its full potential, unlocking unique flavours and aromas particular to its origin and processing method. After roasting, the individually roasted beans are blended, producing a specific coffee type that is then prepared for consumption.

It is also possible to roast these coffees in a single roasting process, which means that the different coffee beans making up a coffee are assembled and roasted in the same roaster.

There is one golden rule when you are looking for the perfect roasting degree: you can roast as much batches as you want, but you must taste each batch that you roast.
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The First & Second Crack of Beans During Roasting

The first and second cracks are critical milestones in the coffee roasting process, each marking a distinct phase of chemical and physical changes within the coffee beans. During the first crack, you'll often hear a sound similar to popcorn popping. This occurs due to the rapid expansion of water vapour and carbon dioxide within the beans, causing them to crack open. The first crack typically happens 196-205°C (385-401°F) and signifies the transition to light roasts. At this point, the beans have lost most of their moisture, and the flavours start to evolve from grassy and herbal to more complex profiles, including floral and citrusy notes.

The second crack resembles the sound of cracking embers. It usually takes place between 225 and 230°C (437-446°F) and indicates that the beans are entering dark roast territory. Unlike the first crack, the second crack marks the breakdown of the bean's cellular structure, and the oils begin to migrate to the surface. This results in darker, oilier beans with flavours that skew towards smoky, earthy, and chocolate profiles.

Both cracks represent a series of chemical reactions, including Maillard reactions and caramelization, which give coffee its rich flavour and aroma. Skipping past the second crack can result in over-roasted or burnt beans, while stopping before the first crack will leave you with underdeveloped flavours. Therefore, the timing and temperature of these cracks are pivotal for achieving the desired roast level, whether it's a light or a dark roast.
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The Degassing of Coffee Beans After the Roasting Process

After roasting, coffee beans go through a degassing period where they release carbon dioxide, a natural byproduct of the roasting process. This step is crucial to avoid oxidation and maintain freshness.
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The Different Types of Coffee Roasts

The impact of roasting on the coffee's character varies significantly between different roast levels:


  • Unroasted coffee beans are not favourable for consumption and have a grassy aroma due to its raw state.
  • Light roasts preserve more of the coffee's original character, bringing out bright, floral, and fruity notes.
  • Medium roasts achieve a more balanced flavour profile, leaning towards cereal, caramel and nutty nuances, thanks to moderate temperatures and roasting time.
  • Dark roasts are taken to higher temperatures for a more extended period, resulting in a robust body with smoky and chocolate undertones.This kind of roast tends to override the intrinsic qualities of the bean, focusing instead on the flavours developed through the roasting process itself.

Characteristics of Unroasted Coffee Beans

Unroasted green coffee beans are the raw material before roasting. They are a pale yellow-green colour and have a hard, dense texture. Being not yet roasted means these beans have not yet developed the complex flavours and aromas that are unleashed through the roasting process. It is far from any of the roasted categories in terms of flavour and aroma.

check iconTemperature: Unroasted

check iconAlternative Names: Green coffee beans

check iconColour: Green

check iconTaste: Herbal, grassy, astringent

check iconTexture: Hard, dense, grain-like

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Characteristics of Light Roast Coffee

Light roast coffee is a light brown bean that has no visible oils on the surface. Compared to medium and dark roasts, the flavours here are much more nuanced, and the coffee is lighter in body. It's the least 'transformed' of the roasts, enhancing coffee bean's characteristics such as fruity, vegetal and aromatic floral notes.

check iconTemperature: 196-205°C (385-401°F)

check iconTaste: Development of a “primary” profile, with floral, vegetal and fruity notes

check iconTexture: Dry, matte finish

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Characteristics of Medium Roast Coffee

Medium roast coffee occupies the middle ground and becomes a rich brown colour which may have a slight sheen but generally non-oily. Medium roast acts as the bridge between light and dark, offering moderate acidity and a fuller body than light roast but not venturing into the intense, low-acidity territory of darker roasts.

check iconTemperature: 210-220°C (410-428°F)

check iconTaste: Development of a “secondary” profile, balanced with notes relating to cereals and their derivatives

check iconTexture: Smooth, slight sheen but not oily

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Characteristics of Medium-Dark Roast Coffee

Medium-dark roast coffee is darker still and can display some oil in its deep brown colour. This roast maintains less acidity compared to light and medium roasts but hasn’t reached the strong, smoky traits of a dark roast. It gives you a robust flavour without going to the extreme.

check iconTemperature: 225-230°C (437-446°F)

check iconTaste: Development of a “tertiary” profile with more pronounced notes of spices, cocoa, wood, ash or tobacco

check iconTexture: A glossy sheen, small droplets of oil

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Characteristics of Dark Roast Coffee

Dark roast coffee undergoes the most transformative process. Compared to all other roast types, dark roast coffee has the least acidity and the boldest flavours, appealing to those who want an intense cup of coffee.

check iconTemperature: 240-250°C (464-482°F)

check iconTaste: Spices, dark cocoa, wood, ash or tobacco

check iconTexture: Oily, with a shiny, slick surface

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The Myth of Caffeine Content Varying Across Different Coffee Roasts

One of the most enduring myths about coffee is the idea that darker roasts contain more caffeine. This misconception likely arises from the robust, intense flavours of dark roasts, which people often equate with strength. However, it's essential to understand that caffeine content remains relatively constant throughout the roasting process. In fact, some argue that lighter roasts may contain slightly more caffeine because they are less exposed to heat, which can break down caffeine molecules despite the difference being hardly noticeable.

The 3 main factors influencing the caffeine quantity in your cup is the coffee species (Arabica or Robusta (Robusta containing more caffeine)), the quantity of ground coffee you use for one serving, and, finally, the quantity of water going through the ground coffee ending in your cup.

The brewing method then have a more significant impact on caffeine levels than the roast itself. Espresso brewing, for example, uses pressure to extract flavours quickly, resulting in a concentrated taste, with a certain amount of caffeine. If, for example, the same coffee, same quantity, is prepared with the filter-drip method and with a larger amount of water, then the taste will be less concentrated, the texture will be juicier, but the caffeine content will be higher as it increases with the quantity of water used.

For more information on the different coffee drink types, read our article about the different coffee drink types and espresso drinks.

How to Choose the Right Coffee Roast for You?

Whether you like the nuanced floral notes in light roasts or the bold intensity of a dark roast, your preference is the ultimate guide. Experiment with different Nespresso capsules, which offer a spectrum of flavours and roast levels, to find your ideal match.

What Makes Nespresso's Roasted Coffee Capsules Special?

Nespresso's wide range of coffee capsules are expertly roasted and encapsulated to preserve freshness, flavour, aromas and prevent oxidation. With Nespresso, you're not just having coffee; you're partaking in a carefully curated experience that showcases the beauty of the roasting process. Elevate your coffee experience by shopping Nespresso's selection of coffee capsules today.
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