Roasting Coffee Beans at Home

Roasting Coffee Beans at Home

One of the best cups of coffee you will ever enjoy is the cup you roast at home. Because you roast the coffee in your home, you are guaranteed fresh coffee that is roasted to your exact taste. When you understand this roasting process, you can create a perfect cup of coffee.

Another benefit of roasting your own green coffee beans at home is you can choose light, medium, or dark roast. If you try it once, you will become addicted to the process. Many individuals think it will take a lot of equipment and effort, but with this guide, you can start roasting your own beans within a few minutes.

You will only need a few supplies and a source of green coffee beans. It is also wise to understand the process of roasting green coffee beans from start to finish. This understanding will give you a firm grasp of how roasting affects the flavors of your coffee. This ultimate guide contains everything you will need to know to make an excellent cup of home-roasted coffee.

What is Coffee?

Before we get into how to roast coffee, we should talk about coffee. It comes from a small red fruit that goes through a variety of stages before it is poured into your cup each morning. The coffee must first be processed to eliminate the outer skin, pulp, and inner parchment skin.

Once these three items are removed, the inner seed is dried. This inner seed is what most individuals call the coffee bean. This dried bean becomes a green coffee bean that is seen around the world for home roasting.

Similar to a dry pinto bean, the coffee bean can be stored for long periods without issue. It will still be completely fresh when it goes through the roasting process. Some inexperienced individuals have tried to create coffee without first roasting the beans.

Unfortunately, the drink was bitter and acidic, which made it virtually impossible to drink. Coffee is much more enjoyable when it is roasted because roasting can help coffee develop a variety of unique flavors and aromas.

Roasting Process

The first vital point to remember when you are going to roast coffee beans at home is green coffee can change drastically during this process. The moisture is forced out of the coffee bean when it is roasted. This force out makes the seed dry and expand.

Some natural sugars in the bean will convert into CO2 gas, and the others will become caramelized into the wonderful flavors that create the sophisticated taste of the coffee. The roasted coffee bean will be around 18% lighter but 50 to 100% bigger. You will learn more about the chemistry behind roasting in the section labeled chemistry.

If you plan to roast your own coffee, you will need three vital supplies. The first supply is the green coffee bean, which can be the hardest part depending on where you live. You can check with local coffee shops or look for roasters in your area.

The second supply is a source to roast the bean. A variety of different roasters are available. Some individuals even use a popcorn machine to roast green coffee beans. We will discuss the four top choices in the next section.

Finally, it would be best if you had a place to store the coffee beans once you have roasted them. Almost immediately, the coffee begins to ‘degas’ which means it begins to lose quality. If you can use an airtight container, the coffee beans will remain fresh longer. However, regardless of the container used, the coffee bean will still lose flavor and aroma after seven to ten days.

One thing to remember when roasting coffee beans is the process produces a lot of smoke. It would be best if you always used an area in your home with proper ventilation. Another item is that the coffee beans must be kept in constant motion, so they do not scorch.

Ways to Roast Coffee

When discussing home roasting options, you may hear a variety of advice about the methods. It is easy to dive into the world of roasting your coffee beans at home. However, it is suggested to choose your process from one of the following: pan/grill roasting, oven roasting, popcorn machine roasting, or home coffee roaster.

Each of these methods has advantages and disadvantages associated with it. The cheapest way is to roast in a pan or oven, but you can get the best results from a popcorn machine or home roaster. These two methods are consistent and straightforward.

Popcorn machines can be purchased for around $25 to $30, but a home roaster can range from $150 to $500. Cheap roasters are typically not well made and may not last as long as a more expensive model. If you plan to purchase a roaster, a medium to a high level is your best bet.

Some people like to use a popcorn machine because it keeps the bean in constant motion. However, these machines were made for popcorn, not coffee beans. Using a popcorn machine to roast coffee beans may void the warranty and shorten the life of the device.

When choosing a popcorn machine, you should pick the one that heats on the sides and not on the bottom. If the machine heats from the bottom, you will not get an even roast. More importantly, the chaff can catch fire.

Some people like to roast coffee beans in the microwave. This method is not an excellent choice for roasting coffee beans because you will get inconsistent roasting and mediocre tasting coffee. Each of the four processes mentioned above will be described in detail later in this article.

Stages of Roasting Coffee

Some expert coffee roasters would identify ten levels of roasting beans. A bean can go through each of these levels but not necessarily should go through them. The level reached depends mostly on the person roasting the beans.

Stage 1: Green– At first, the beans retain their pure green essence. They maintain this green color even as they start to heat.

Stage 2: Yellow– As the beans roast, you will notice a grassy odor. They will also begin to turn a yellowish color.

Stage 3: Steam– Soon, you will notice steam coming from the beans. This steam comes from the water inside the kernel as it is evaporating.

Stage 4: First Crack– This step is sometimes referred to as cinnamon roast. The beans are being caramelized, which creates a cracking sound. This sound is similar to popcorn popping.

Stage 5: City Roast– After you hear the first crack, the beans are considered to reach City Roast. This stage is the minimum level of roasting that is typically accepted.

Stage 6: City Plus Roast– As the beans continue to caramelize and the oils migrate, they will swell and reach this stage. This stage is the most common level of roast.

Stage 7: Full City Roast– This stage is a darker roast than City Plus Roast, and it takes the coffee beans to the verge of what some refer to as the second cracking.

Stage 8: Second Crack or Full City Plus Roast– This cracking is much more violent than the first cracking. It reveals various layers of the intensity of flavors.

Stage 9: Dark Roast or French Roast– During this stage, the sugars burn as much as possible without ruining the taste. The smoke from the beans will be pungent, and the overall structure of the seed will break down. This stage is the last stage offering tasty flavoring.

Stage 10: Burn– If the beans reach this stage, the smoke will have a horrible smell, and the coffee beans have burned.

As the coffee beans reach each of the above stages, they will begin to shed their outer skins. This leftover shell is called chaff. The chaff must be removed from the beans. You can accomplish this removal by using two colanders.

As soon as roasting is complete, it would be best if you placed the hot beans directly into one of the colanders. Then, you will dump the beans from one strainer to another. It would be best if you went back and forth a few times.

This movement will help to remove the chaff. If you are unable to remove all of the chaff, you should not be too worried about it. As long as it is a small amount that is left behind, it will not affect the taste of the coffee.

Roasting Preferences

Every coffee drinker has a favorite stage of roasting. Most individuals do not know all of the names of the steps. Typically, coffee roasting is described as light, medium, medium-dark, and dark roast.

For example, both Full City and Full City Plus are dark roast coffee, and both roasting processes are similar. However, a significant difference exists between a City and a French Roast during the roasting process.

The internal temperature of a coffee bean rises as the beans roast. This rising and the increasing heat of the roaster provides various considerations. The internal temperature of the bean at the time of removal determines the type of roast.

Light Roast

The internal temperature of your coffee beans should be between 356 and 401 degrees Fahrenheit to get a light roast. Light City, Half City, and Cinnamon roast are considered light roasts. Each of these stages falls somewhere around the first crack.

The bean surface is still completely dry at this stage and will be dense or hard. If you like higher acidity coffee brews, this preference is perfect for you. Some people say this is the safest kind of roast to do at home because it requires a lower temperature and time.

Medium Roast

Between 410 and 428 degrees Fahrenheit is the temperature of a medium roast. The beans will look different from the original green coffee beans, but the surface will still be relatively dry. Medium roast is considered to be anything between the first and second crack.

This type of roast has a more mid-level acidity, which makes it much more popular with avid coffee drinkers than the light roast. The body of these coffee beans is more fuller. People are also able to manage the temperature more comfortable.

Medium-Dark Roast

This category encompasses a much larger degree of roasting distinctions, including Vienna Roast, Full-City, and Full-City Plus. The temperature window for this roast is smaller than some of the others.

The temperature range is from 437 to 446 degrees Fahrenheit. This temperature is typically reached right before the second crack. It is denoted by patches of oil. The flavors are more predominant alongside the various notes, which creates small doses of spice and a more massive body.

Dark Roast

The last type of roast is called dark and includes French Roast, Italian Roast, and Espresso Roast. This roast’s temperature falls around 464 degrees Fahrenheit. It is vital to ensure the temperature of your beans does not reach 482 degrees Fahrenheit or higher.

When the temperature reaches over 482 degrees, it can be extremely tricky and can even become dangerous if the proper equipment is not being used. The beans have an oily surface and low acidity.

It would help if you pulled the beans out during the second crack because the roasting flavor begins to change drastically. You should be careful if you are looking for a dark roast because anything beyond this point becomes burnt and a fire hazard.


Some individuals would say it is not necessary to have an understanding of the chemistry behind roasting coffee beans, but it can come in handy. You are creating a chemical transformation when you roast coffee beans.

This transformation is called the Maillard reaction, which was named after French chemist Louis-Camille Maillard. A variety of foods such as seared steak, cookies, and bread go through this type of response.

It involves a chemical reaction between sugars that are reducing and amino acids. The Maillard reaction is what gives browned food its unique and delicious flavors. The chemical constituents determine these flavors in the food.

In coffee beans, 800 compounds are present. These compounds are chemically changed from the icky flavors of the green coffee bean to the aromatic flavors found in roasted coffee beans. Raw beans taste nothing like roasted beans due to this transformation.

As beans are roasting, they emit CO2 gas. This CO2 will help to ensure the coffee beans are naturally preserved by replacing oxygen. Oxygen makes coffee beans stale and can ruin the beans.

However, CO2 can be a double-edged sword because too much CO2 can create an excess of crema, which is not good. A lack of CO2 will make a stale cup of coffee. So, it is best to wait about twelve hours before sealing the beans into a container to allow the initial CO2 to leave the beans.

CO2 pressurization is created when you seal the roasted beans too quickly. This pressurization is what causes the lid of the containers to pop open. If you do not wait to store the beans, it can also create a nasty flavored coffee due to too much CO2.

It is also best to give roasted coffee beans a full day to mature. If you wait for at least 24 hours before grinding or brewing the beans, you will get a full-bodied flavor. Most coffee beans once roasted need to be used within seven days.

The purpose of roasting is to get fresh coffee. Unfortunately, oxidation will begin to significantly affect your coffee beans after about seven days, even if they are correctly stored. The coffee bean will become stale and begin to lose flavor.

Pan or Grill Roasting


  • Fast
  • Convenient
  • No additional purchases needed


  • Creates lots of smoke
  • Hard to get the right temperature
  • Must continuously stir

Most people already have a pan or grill in their homes. This fact makes this the most popular method for cooking beans. If you have never used a pan or barbecue to roast, you may want to find a tutorial before starting.

Overcooking coffee beans is common when you use a pan or grill. It is also essential to avoid using any coated pan because it will harm the flavor of the coffee.
The first step in roasting beans using this method is to ensure you have proper ventilation.

It would be best if you turned on any available exhaust fans and open windows. Another choice is to grill the beans outside the home to prevent smoke from entering the house. Wherever you decide to roast the beans, the temperature should be at 450F.

Getting the right temperature is the hardest part of this method. You may need to experiment a few times before you get it right. Once the temperature is correct, add a small layer of beans to the bottom of your pan. You must have enough room to continuously stir the beans without knocking them out of the pan.

You must stir continuously to ensure the coffee beans are heating evenly. After four to five minutes, you should hear the first crack, which means the seeds are considered to be a light roast.

After six to seven minutes, you will hear the second crack, which indicates the beans have reached a medium roast. It is critical to remove the seeds shortly after the second crack because they will quickly burn.

After you remove the coffee beans from the heat, you should chaff them as quickly as possible to limit the mess. The seeds should also be cooled as rapidly as possible to help ensure the best flavors.

The beans will need to de-gas for at least twelve hours before you store them. If you want a dark roast or French roast coffee, this method is not the best choice. Three other ways will be explained that may be more appropriate for this type of roast.

Popcorn Machine Roasting


  • Automatically rotates beans
  • Easier to get the right roast
  • Less work


  • Not designed for coffee beans
  • Fire hazard
  • More expensive than pan/grill

You can purchase two different styles of a popcorn machine. The first style is a stovetop popcorn maker. This style of popcorn popper is similar to a pan on top of the stove. You will follow the same general instructions if you are using a Whirley-Pop popper kit.

However, the temperature should be around 400F. You will also have to crack the handle as the beans heat to ensure an even roasting. The other type of popcorn popper is a hot air machine. This type of device is an excellent choice for the beginner who is starting to roast coffee beans.

Using this style of a popcorn machine, it will only take a few minutes to roast coffee beans. This machine also makes it easier to experiment with the roast. You can make it a light roast or a dark roast without any issues.

To use this machine requires you to have all of the materials gathered in one place because the process goes quickly. The device will only need to preheat for about 30 seconds. Once the machine is heated, a half cup of beans can be added to the container.

The machine should be a machine with a side vented heat to help to make the roasting process safer. It is essential to ensure you do not overfill the device because the beans will not be able to rotate correctly.

Because this process will only take about five minutes to go through all ten stages of roasting, the popper should never be left unattended. It is best to stay close by the machine to monitor the roasting process closely.

As the beans heat, you will hear the first and second crack using a popcorn machine similar to roasting in a pan or on a grill. When you have the perfect roast, you should first turn the popper off. After the machine is off, you can dump the roasted beans onto a baking sheet.

Using a baking sheet to remove chaff is an alternative to using a strainer. When you place the beans on a baking sheet, it also allows them to cool faster. It would be best if you remembered to wait at least 12 hours before storing the roasted beans.

Oven Roasting


  • No additional items needed
  • Easy to adjust the temperature
  • Convenient


  • Slower
  • Hard to get the perfect roast
  • Lots of smoke

This method of roasting beans will produce the most amount of smoke. If you do not have excellent ventilation, you may want to consider choosing a different approach. You may want to open all of the windows in the house and turn on ceiling fans.

After you figure out the ventilation issue, you will start by setting the oven at 500F. With different ovens, temperatures will vary. It is suggested to start at 500F and experiment to adjust the temperature up or down.

A perforated tray works best when you are using the oven to roast. However, it would be best if you were sure that beans could not slip between the holes. When you spread the seeds, you should only spread them one layer deep and not stack them.

As the beans roast, they will expand and get stuck in any large holes. If you do not have a perforated tray, it is possible to use a regular oven tray. An oven tray will require you to line it with baking paper. As the beans roast, be sure to give the tray a shake once in a while.

Whether you use a perforated or oven tray, you should place it on the middle shelf. This area is the place that has the most consistent temperature. It will take between five and seven minutes before you will hear the first crack, which indicates the beans are at a light roast.

After the second crack, some people will wait about 60 seconds before removing the coffee beans. You will need to use a colander to remove the chaff as soon as possible. Heatproof mittens will help protect your hands.

Home Roasting Machine


  • Built for coffee roasting
  • Long-lasting
  • Easy to use
  • Simple to clean


  • Expensive
  • Massive

Another option for roasting coffee beans is to purchase a home roaster. A roaster is more consistent than any other mentioned method. It is also probably the most expensive of the methods mentioned. So, unless you are serious about roasting your own coffee beans, you may want to try a different approach first.

Regardless of the method used, coffee bean roasting will produce a lot of smoke, which means ventilation is still a concern. So, the first step is to ensure you have an excellent means of ventilation before you begin this process.

The next step is to read the manufacturer’s instructions. Each of these machines has different directions. However, the overall process begins with turning on the device and following the manufacturer’s instructions.

As with the other methods, you should monitor the entire process to ensure your beans do not burn. You are still listening for the first and second crack to indicate when you have a light or a medium roast. The rest of this procedure is the same as the others.


The above four methods are just a few of the ways you can use to roast coffee beans at home. The various options are limitless as long as you have a container and a heat source. One of the only ways to guarantee a fresh cup of coffee is to roast and grind your own beans.

The roasting at home process is relatively easy. You can also create your own distinctive and unique flavors for your morning cup. If you are not finding that perfect taste, you should try experimenting using various methods and different lengths of time.

Eventually, you will get the best combination. Now that you know how to roast coffee beans at home, have fun finding it.

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