Coffee Roasting Machines

Roasting coffee is a crucial step in the process of making delicious coffee. A coffee roasting machine transforms raw green beans into aromatic and flavourful coffee beans. There are various types of coffee roasting machines and techniques available for coffee roasting. Understanding this process can provide insight into how coffee beans are roasted. 

When roasting coffee, the beans are stirred to roast evenly. The roast’s intensity depends on the time and temperature. The beans expand and release oils and gases, giving coffee its unique flavour and scent.

Coffee Roasting Machine Types

There are different types of coffee roasting machines that have their own benefits and features. The most popular ones can be found on the market and have different options to choose from. They are made to help you roast coffee beans to your preferred level of roast, whether it’s light, medium, or dark. Knowing the different types can help you choose the one that suits your needs and preferences.

Drum Roasters

There are different types of coffee roasting machines, and one of the traditional ones is the drum coffee roaster. It uses a rotating drum to roast the coffee beans evenly. It can handle big batches of coffee and is heated by gas, electricity, or wood. The beans are roasted as they touch the hot drum.

Drum roasters are good for consistent coffee roasting and easy to use, great for beginners.But, they roast slower than other types of roasters, which is bad if you need to roast a lot of coffee quickly. They are also not as precise in controlling temperature and timing.

Some drum coffee roasters are semi-commercial and can be used in small coffee shops or for small scale coffee roasting setups. They have a capacity between commercial and home drum roasters, and are made for small scale roasters who want to roast coffee regularly. These roasters can meet the needs of those who want to roast coffee on a small scale.

A coffee roasting machine uses a rotating drum to control how coffee beans are roasted. The drum moves the beans around, exposing them to different temperatures and conditions. The coffee roaster can adjust the drum speed or temperature to get the desired roast level and flavour.

Perforated Drum Roasters

Perforated drum roasters are like traditional drum roasters but have holes in the drum for better airflow and temperature control. This makes the roast of the coffee beans more consistent and even. They can run on gas, electric, wood, or charcoal.

A coffee roasting machine with holes in the drum is better for making good coffee. The holes help you see the beans while they roast so you can make sure they don’t burn. The holes also let air flow through, which helps make the coffee taste better.

perforated drum roaster

Centrifugal Coffee Roaster

Centrifugal coffee roasters roast coffee beans differently than traditional rotating drum roasters. They use a spinning chamber and hot air in the coffee roasting machine to create a centrifugal force that evenly distributes heat and ensures consistent roasting.

You have the ability to adjust the temperature and duration to speed up or slow down the coffee roasting process. Centrifugal coffee roasters are efficient in terms of speed, but they also have some drawbacks.The spinning action doesn’t always provide enough heat to the beans, which may result in a weaker flavour. Additionally, the spinning motion can generate a lot of smoke.

Fluid Bed Coffee Roaster

The fluid bed roaster is a coffee roasting machine that uses hot air to roast beans. The coffee beans are placed in a chamber and roasted evenly by blowing hot air through them.

Fluid bed roasting is a new way of roasting coffee beans. It uses hot air to roast the beans evenly. This makes the coffee taste and smell consistent. Fluid bed roasting is good for small-batch roasting and lets you try different roasting styles.

When roasting beans, hot air is used to suspend them. This helps prevent smoke or ash from contaminating them. Fluid bed roasters are also more energy efficient because the hot air can be reused to heat the beans, which saves on energy costs.

Home Coffee Roasting Machines

More and more coffee drinkers are becoming interested in home roasting and buying home coffee roasting machines. These machines allow coffee lovers to roast their own beans and create a unique blend that suits their personal taste. Home roasting is not only convenient but also cost-effective compared to buying pre-roasted beans. With a home coffee roasting machine, you can enjoy the comfort of roasting coffee in your home and personalise your coffee experience.

To roast coffee beans at home, a coffee roasting machine is used. The machine heats the green coffee beans with hot air and evenly roasts them by agitating them. The machine has a user interface that allows the user to control the temperature and airflow rate. The user can set the temperature and time for roasting according to their preference. The duration of the roasting process varies from a few minutes to more than an hour, depending on how dark the user wants the roast to be.

Roasting coffee at home is an excellent way to try out different levels of roasting and make your own custom blend of coffee. Through the roasting process, each bean’s exclusive qualities are highlighted, leading to a unique flavour profile that can be tweaked to your liking.

The Coffee Roasting Process

Roasting coffee is the way we make coffee taste good. It takes around 15-20 minutes and depends on the roaster and how roasted we want the beans to be.


Before roasting coffee, the beans must be dried by heating them to 65-93 degrees Celsius for a few minutes.


After drying, the beans will start to turn yellow and give off a grassy smell.

First Crack

When the coffee roasting machine heats up, the beans inside it also get hotter until they reach 200 degrees Celsius. Then, the beans make a cracking sound called the first crack. This means the oils are being released and the beans are getting bigger.

Second Crack

When roasting coffee beans, they reach 220-230 degrees Celsius and enter the second crack. This causes them to break down and release more oils.


After roasting the coffee beans, they need to be cooled quickly to prevent over-roasting.

When roasting coffee, the coffee roaster checks the temperature and colour of the beans and adjusts the heat and airflow to make sure the roast is consistent. They need to balance the temperature, time, and airflow to get the right taste. Small changes can make a big difference in the final coffee taste.


Degassing coffee is the process by which carbon dioxide buildup in roasted coffee is released over time. This process begins immediately after the roasting process and significantly impacts the flavour of the coffee.

Gases, including carbon dioxide, form within the coffee beans during the roasting process. To achieve the optimum flavour, coffee should be allowed to degas properly. The correct way to degas coffee is to let it rest for approximately 10-14 days after roasting.

Allowing the coffee to degas during this period helps strike the perfect flavour balance and ensures that the most desirable characteristics of the roast are highlighted.

roasting coffee first crack graph

Coffee Roasting: The Art and Science Behind It

Roasting coffee is both an art and a science. You need to know the chemical reactions that happen during the process. Understanding a few key concepts is crucial to making a great cup of coffee.

Maillard Reaction

When coffee is roasted, a chemical reaction happens called the Maillard reaction. This reaction makes new compounds that give coffee its special taste and smell. Different flavours like chocolate, nutty, and caramel come from this reaction.


When coffee is roasted, it goes through caramelisation. This process breaks down the sugars in the beans and makes the coffee taste sweeter.


The sourness of coffee depends on its acidity. Acidic coffee can be low or high, with lightly roasted coffee being more acidic and dark roasts being less acidic.


Different coffee roasts affect the body of the drink. Lightly roasted coffee has a lighter body while dark roasted coffee has a thicker and heavier body.

Roast Degree

The way coffee beans are roasted affects their taste. The roast degree depends on how long and how hot they are roasted. Different roasts affect the coffee’s acidity, sweetness, and body. Light roasts are more acidic and have a lighter body, while dark roasts are less acidic and have a thicker body.

To make good coffee, you need to know about coffee roasting. This helps you change the taste by adjusting the acidity, sweetness, and body. The roast level is not the only thing that affects the flavour. The type of beans, where they’re from, and how they’re processed also matter.

Maillard Reaction

Examples Of Different Coffee Roasts

Light Roast Coffee

When it comes to coffee roasting, the light roast is a popular choice for those who prefer a milder flavour and subtle aromas. This type of roast is achieved by roasting the beans for a shorter time and at a lower temperature compared to medium or dark roasts. The light roast coffee has a light brown colour, a lighter body, and acidity. It also has a higher caffeine content and a more prominent flavour of the origin beans. Additionally, it offers a delicate flavour profile with distinctive notes.

Medium Roast Coffee

Medium roast is a popular choice. It has a dark brown colour and a well-balanced flavour and aroma. This type of roast is achieved by roasting the beans for a longer period of time and at a higher temperature than light roasts. Medium roast coffee has a fuller body and a moderate level of acidity. It offers a balanced flavour profile that highlights the origin of the beans. Additionally, it has a moderate caffeine content and a variety of complex flavour notes.

Dark Roast Coffee

Dark roast coffee is famous for its strong taste and smell. It has a very dark brown colour and is roasted for a longer time and at a higher temperature compared to other roasts. The beans’ origin contributes to its smoky flavour, and it has a lower caffeine content with a more robust flavour profile. It has a strong body and low acidity, making it a popular choice among coffee drinkers.

Heat Sources

Electric Coffee Roasting

Electric coffee roasting machines are a common way to roast coffee. They use electricity to heat up the coffee beans. Electric roasters are easier to use and more precise than gas roasters. They can control the temperature very accurately, which is important for making sure the roast is consistent.

Electric coffee roasting machines are better for the environment and use less energy. They are a good choice for sustainable coffee roasting.

Electric coffee roasting machines are to use for small batch roasting. They make coffee that tastes balanced, bright, and clean with hints of sweetness and acidity. They are also smaller than gas roasters and can fit in small spaces.

Electric coffee roasting machines have computerised controls and data logging, which makes the process consistent. But some coffee experts like gas roasters because they give a smokier and more complex taste. Gas roasters are usually cheaper than electric ones.

Gas Coffee Roasting

There are different ways to roast coffee, and one of them is gas roasting. It uses a gas flame as heat and is cheaper than electric roasting. It also gives better temperature control.

Gas roasters are commonly used in the coffee industry because they last a long time. They are not as energy-efficient as electric roasters and produce more emissions. But, gas roasters can enhance the taste of coffee by bringing out a full-bodied and earthy flavour with hints of chocolate and nuttiness.

Wood Coffee Roasting

Roasting coffee with wood means using wood as a heat source. It’s not as common as electric or gas roasting, but it’s gaining popularity because it can give coffee a special taste and smell.

This way of roasting is old-fashioned and slower than using electricity or gas. It can make the taste more interesting, but it’s hard to control the temperature and get a steady roast. 

Roasting coffee with wood adds special flavours that are smoky, woody, and spicy. It’s great for showing off the unique taste of where the beans were grown.

Wood roasting can be a better option if the forests are managed responsibly and replanted. It can give unique flavours depending on the wood used, but it’s more expensive and requires more time and labour.

Charcoal Coffee Roasting

Charcoal roasting is a unique way to roast coffee beans using charcoal as the heat source. It’s a complicated process that requires more expertise than traditional methods. The coffee produced through charcoal roasting is full-bodied, robust, and has a distinct smoky flavour due to the high heat and intense smokiness involved. Charcoal coffee roasting can also be used for small batch roasting.

Slow roasting coffee keeps its natural flavours and smells. This makes it taste great with hints of dark chocolate and nuts. But, charcoal roasting takes more time and effort, and is more expensive because of the cost of charcoal.

There are different ways to roast coffee, each with its own benefits. Electric roasting lets you control the temperature exactly, while gas roasting lets you control the flame better. Wood roasting can add interesting smoky and woody flavours, and charcoal roasting makes a strong, smoky coffee.

Frequently Asked Questions

Is it worth home roasting coffee?

Home roasting coffee offers several advantages, including the ability to control roast levels, freshness, and ultimately, the flavour of your coffee. It can be a rewarding hobby that allows coffee enthusiasts to explore different bean origins and roasting profiles. While it requires an initial investment in equipment and time to learn, many find the personalised results well worth the effort.

How do companies roast coffee?

Companies, from small local roasters to large commercial operations, use various machines and techniques to roast coffee. The choice of equipment, such as drum or air roasters, depends on the desired roast profile and production volume. Large-scale roasters might automate much of the process for consistency, while artisan roasters often involve more hands-on techniques to achieve unique flavour profiles.

What is the cheapest way to roast coffee?

The most budget-friendly method for roasting coffee at home involves using items you might already have, such as a heavy frying pan, an oven, or a popcorn popper. These methods, while accessible, require careful attention to roast evenly and avoid burning the beans. For those serious about roasting, investing in a home roasting machine could offer a balance between cost and quality control.

Should you roast coffee fast or slow?

The roasting speed can significantly impact the flavour and aroma of the coffee. A slower roast allows for a more even development of flavours but requires precise temperature control to avoid underdeveloped or baked tastes. Faster roasts can highlight bright, acidic notes but risk uneven roasting and bitterness. The best speed depends on the desired flavour profile and the specific beans being roasted.

How soon after roasting can I drink coffee?

It’s generally recommended to wait at least 24 hours after roasting before brewing coffee to allow for degassing. However, coffee often reaches its peak flavour a few days to a week after roasting, depending on the roast level and bean type. Experimenting with timing can help you find the perfect window for your taste preferences.

Is coffee roasting sustainable?

Sustainability in coffee roasting can be approached in several ways, including using energy-efficient roasters, sourcing beans from farms that employ sustainable practices, and minimising waste. Some roasters also use renewable energy sources and invest in carbon offset programs to further reduce their environmental impact.

What is the best way to roast coffee?

The best way to roast coffee depends on personal preference, the specific beans, and the available equipment. Experimenting with different roasting methods and times can help you discover what works best for you. Whether you prefer the hands-on approach of a pan or the precision of a dedicated coffee roasting machine, the goal is to achieve a roast that highlights the beans’ best qualities.

Scroll to Top