Differences in taste depending on the roaster

- An important factor that determines the quality of a cup of coffee -

The taste of coffee is not only greatly influenced by the "origin of the beans" or the "degree of roasting." In fact, the type and structure of the roasting machine used to finish the beans is also an important factor in determining the characteristics of the flavor. Even if the same beans are finished to the same degree of roasting, differences in the roasting machine will result in differences in aroma and mouthfeel. In this article, we will explain in detail the differences in taste while sorting out the characteristics of the most common roasting machines.

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Drum roaster: the most common style

The drum roaster is the most widely used roaster around the world. The internal drum (cylinder) rotates and roasts the beans while heating them with a gas flame or electric heater. Heat is transferred by conduction through the metal of the drum and by hot air inside.

The drum roaster's defining feature is its "well-balanced finish." The heat is distributed relatively evenly, allowing the beans to be thoroughly cooked all the way to the center. As a result, it tends to produce a full-bodied coffee with a harmonious balance of aroma and sweetness. It is favored by roasters looking for a classic dark roast or a consistent blend.

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Hot air roaster: clean and vibrant flavor

On the other hand, hot air roasters have been gaining attention in recent years. They do not use drums, but instead blow powerful hot air directly onto the beans. Because heat is distributed quickly and evenly throughout the beans, the roasting time can be shortened and controlled.

The taste is characterized by a clean and transparent flavor. The bright fruitiness and acidity stand out, allowing the individuality of the single-origin beans to be directly expressed. This method is popular with roasters who prefer a light mouthfeel and cafes that focus on light roast coffee.

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Semi-hot air roaster: a balance between tradition and innovation

The semi-hot air roaster is somewhere between the drum and convection roasters. The beans are rotated and roasted using both the heat of the drum and hot air. This semi-hot air roaster is widely used in modern roasters.

Its defining feature is its "well-balanced, high degree of flexibility." Because the heat can be precisely adjusted, it can produce a wide range of roasts, from light roasts that bring out the acidity to rich, dark roasts. This allows the roaster to easily reflect their skills and expressiveness, and it has become mainstream in the world of specialty coffee in recent years.

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Differences in roaster materials also affect the taste

Not only the type of roaster but also the ingredients are factors that affect the taste.

• Cast iron drum : It has high heat retention and heats up slowly, which tends to produce a rich, sweet flavor.

• Stainless steel drum : Fast heat conduction makes it easy to produce a sharp, clear flavor.

• Copper drum : It has very high thermal conductivity and can quickly transfer heat to the surface of the beans, which helps bring out their aroma.

As you can see, even with the same roasting method, the flavor that can be expressed will vary depending on the ingredients.

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The nuances of roasting change between large and small roasters

The size of the roaster also affects the taste. Large roasters are stable and can roast large amounts of beans evenly. However, they tend to produce a more full-bodied flavor. Conversely, small roasters are more likely to respond to heat changes quickly, allowing for more delicate control of acidity and aroma. Small machines are ideal for sample roasts and unique small-scale roasteries.

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Summary of flavor by roaster

・Drum type : Fragrant and rich, with a good balance of sweetness and bitterness

・Hot air method : Clean and transparent, highlighting acidity and fruitiness

・Semi-hot air type : Can handle a wide range of flavors from sour to bitter, with rich expression

- Materials and sizes : Cast iron is heavy, stainless steel is clear, small is delicate, large is stable

A roaster is more than just a tool; it is a vital partner that helps shape a roaster's expression. The type of roaster determines the taste of each cup of coffee, just as much as the roast level and the origin of the beans.

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Summary: The diverse world created by roasters

Coffee roasting is both a science and an art. Even if the same beans are roasted by the same person, completely different flavors can result depending on the type of roaster. That's why roasters around the world choose roasters that fit their philosophy and pursue the ideal flavor.

Knowing the differences between roasters is the first step to enjoying coffee on a deeper level. The next time you drink coffee, try imagining what kind of roaster produced this cup, and you'll be able to enjoy a richer tasting experience.

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