How to Roast Coffee Beans at Home

For many people, the idea of roasting their coffee themselves seems like too much work – which is true. But the benefits you enjoy from drinking a fresh brew done to your exact tasting and flavor is worth the stress.

One of the main advantages of roasting your coffee yourself is the storage method. When you buy coffee ground, it might be fresh for a couple of days and begin to lose its taste and flavor after a while; the same applies to your coffee beans.

The green coffee beans can last up to a year before losing their taste and flavor; this means you will appropriately utilize the money spent. You can roast a little of your green beans every other week or month until it finishes or until the year ends (whichever happens first).

Why roast at home?

Roasting your coffee at home gives you a great deal of control over your coffee choice. Do you love Kenyans? Awesome, roast it yourself. You wish you didn’t have to drive so far to get my favorite hazelnut coffee? Roast it yourself.

As much as roasting your coffee yourself grants you flexibility in terms of your coffee taste, it is not the only advantage you stand to gain.

As I mentioned above, freshness is vital for enjoying a cup of coffee; the fresher the coffee, the better the taste. You can only enjoy fresh coffee for so long when you purchase green beans. Moreso, green beans are a lot cheaper than roasted beans.

In the long run, after you have perfected your roasting skills and gotten all the necessary equipment needed for roasting, you will realize you are saving a lot more by roasting at home. Also, roasting your beans yourself will broaden your knowledge about coffee.

You would know what to do to achieve a specific taste or aroma; with practice, your palate will improve – who knows? You might become a connoisseur.

What happens while roasting?

The first stage to converting your green beans into the brew you know is roasting. The roasting is done to allow you to grind the beans, which is impossible when it’s still green. The green beans retain a lot of water and have a grassy flavor, making it impossible to be brewed without roasting.

The roasting process triggers various chemical reactions responsible for the aroma and flavor of the coffee. When the beans begin to roast, moisture is forced out of the beans, leaving the beans dry and expanded. This is the first stage of the roasting process, and it is referred to as the drying stage. Shortly after, the beans begin to turn yellow – the yellowing stage.

The essential chemical reaction happens when the beans begin to darken – the browning stage. Reactions like Maillard, Caramelisation, Strecker degradation all occur during the browsing stage. These reactions create the flavor and aroma you know, and it’s also responsible for the sweetness and fruity acidity in your coffee.

The sound of the first crack ends the browning stage. The pressure inside the coffee beans causes the crack; this sound you will recognize by so many popping noises. The beans will attain their second crack when all the water inside has evaporated. The coffee beans continue to get darker and release aromas that smell like carbon.

Most of the sugar in the beans breaks down at this stage; the longer you roast, the more bittersweet the beverage will taste – and the lesser the acidity. If you aim for light to medium roast, you should stop roasting sometime between the first and the second crack. If you prefer the dark roast, you should attain that stage after the second crack.

Ten stages of coffee roasting

If you are a first-time roaster, it will help to know what stage you are at every point during the roasting process; this way, you do not roast beyond the level you want to attain. Here is everything to expect and what each stage means.

  • Green: The green is the color of the beans before roasting; it will retain this color for a bit after the roasting begins.
  • Yellow: The bean’s color will turn yellowish after a while, and you will be able to smell a grassy odor.
  • Steam: You will notice stem coming out of the beans; it’s the water inside the beans evaporating.
  • First crack (cinnamon roast): The first crack signifies the beginning of the actual roasting process. The sugar inside the beans caramelizes, and you will be able to hear a cracking sound – similar to that of popcorn popping.
  • City Roast: The first crack’s sound is the minimum roast level acceptable for grinding and brewing. After the first crack, roasters say the beans have reached city roast.
  • City plus roast: After the first crack, the next level is called city plus roast. This level increases caramelization of sugar and production of oils, with the beans increasing in size.
  • Full city roast: The stage just before the second crack is called full city roast; the coffee beans are darker than the city plus roast.Second crack (full city plus roast): At the second crack, the beans will contain more flavor with layers of intensity, undergoing more violent cracking and entering full city plus.
  • Dark Roast (French Roast): After the second crack, the smoke will become stronger. The beans’ structure will break down, and the sugars will burn more without ruining the taste. If you still want to get a good flavor from roasting your beans, this is the limit you should go.
  • Burn: If you are still roasting at this point, the roast’s smell will go from intense to terrible, and you will end up with burnt beans.

Things needed to roast

Before beginning your roast, you need a few items to perform the process.

Green coffee

Getting green beans might prove to be the most challenging item to purchase for your roasting process – depending on where you live. Check your local coffee shops around you or ask around for roasters in the area you can buy unroasted coffee beans from.


There are various roasters available on the market; a popcorn machine will do a fine job for you. When you want to buy your roaster, you should consider a few things, as the use will determine the type to purchase.


After roasting, you need a place to store your beans that will keep them fresh for as long as possible. Airtight containers are better as they prevent air from getting into your beans. Bear in mind that irrespective of how airtight the container might be, your beans will begin to lose flavor in about a week – don’t blame the container; it’s natural.

A step-by-step guide

Now, you know what to expect while roasting, and you have also gotten the items needed to roast, let’s begin the roasting.

Sourcing green beans

If you are new to roasting your beans at home, you might not be familiar with which beans to buy to attain the brew you love, especially if your coffee taste is limited to the house blend at the café you frequent.

Experiment with little quantity of beans until you are certain of your choices. If you can purchase sample packs, that will be better as they contain beans from various regions. Aside from buying from your local grocery store, another place to check for green coffee is online.

Find out as much information as you can about the coffee before purchasing; there might be a significant difference even among coffees of the same origin. There might also be different processing methods and many other differences you need to know before purchasing.

After purchasing your green coffee, store them in a dry, cool place (preferably room temperature), far from direct sunlight. Doing this will ensure your green beans retains their freshness and quality for a long time.

Your roasting method

There are many ways to roast your coffee at home; each method has its advantages and disadvantages. To make the best choice, consider how much money you want to invest, the quantity of coffee you want to roast, and the level of control you want to have over your roasting variables.

Oven and skillet-roasting: These are pretty affordable options, considering you most likely own the equipment. The disadvantage with this type of roasting method is that it is not suitable for beginners as it requires high-level skill to attain an even roast.

Moreso, airflow control is essential while roasting; you might find it difficult when using this method.

Popcorn machine: This is another roasting method if you intend to roast in small quantities and it produces an even roast. The drawback is that you will reduce your popcorn machine’s life expectancy as it wasn’t created for coffee beans roasting. Also, note that you cannot use a popcorn machine with a mesh screen at the bottom, as this can lead to a fire outbreak.

If you realize that you need to roast more coffee or you will prefer to have more control over the coffee roasting process, you will need to invest in a home coffee roaster.

Deciding on the best brand to purchase will come down to your preference; how much quantity of coffee you want to roast, the level of control you want to have over the roast, or the pre-set and roast profile you want to be programmed on the machine.

All these and more are what should determine your choice.

Setting up your roasting space

While setting up for roasting, ensure the place you plan to roast is well ventilated, not just for the coffee beans but also for yourself. If you must roast indoor, open up windows, or use extractor fans.

The best place to roast is outdoors or an open garage – if you do not have the luxury of roasting outdoor. The reason for roasting outdoor is to ensure smoke from the beans escapes quickly.

It would help if you also had equipment like scales handy to measure the roast quantity per batch. If you are using a popcorn machine to roast, you should get a thermometer. Other equipment like silicon gloves for handling hot materials, a sieve for cooling your beans, and a small fan will come in handy.

Roast your coffee

If you have a roasting machine, you can use the manual to walk your way through the roasting process; you can use pre-sets if you are a beginner until you get familiar with how it works. If you are using a popcorn machine, ensure you do not overfill the machine and be certain there is somewhere for the chaff to escape.

It is essential you constantly move the machine to gain an even roast. Your popcorn machine and the home roaster should do this automatically, but you will need to stir yourself when using the skillet cooker.

Popcorn machines and air roasters should finish in about 8-12 minutes. The drum roaster will take longer – 14-20 minutes because it uses a lower temperature.

Cooling and storage

After your beans attain your preferred roast level, remove them from the heat and leave to cool. Bear in mind that the beans will continue to roast until they are thoroughly cooled – you must act quickly. You should also remove chaff that might be in the beans.

If your climate is cold, allow the beans to cool naturally; if not, use a small sieve and a fan to blow through the beans. Once your beans cool to room temperature, you can store them.

The best way to store your beans is by putting them into a sealed, foiled-lined bag. If you do not own foiled-lined bags, you can put your coffee in airtight containers and keep it in a cool and dark place.

Avoid heat, light, and air from getting into your roasted coffee as those will fast-track your beans to lose taste.

After roasting, do not brew yourself a cup of coffee immediately, as you will need to allow your roasted coffee degas. You can begin to brew a day after roasting for a dark roast, but no later than ten days. For medium or light roast, you can hold off brewing for about two weeks after roasting, but not more than a month.

Factors that might affect your roasting

It will seem like home roasting is easy, but there are certain things, if not avoided, that can lead to disaster for you and your beans.

Do not get used to a particular roast time as certain conditions might need you to adjust your roast time. An example is roasting outside as against roasting indoors. Your machine might not heat up as soon as it should. If you do not factor this into your timing, you will end up with underdeveloped beans or under roasted beans.

The size of the batch can also affect your roasting process. If the batch is too much, the heat might not be evenly distributed. Also, if you are roasting too fast, your beans might not achieve the level of browning you desire.

If you begin roasting at the highest temperature to reduce roasting time, you will end up with scorched beans. While roasting, pay attention to both your reading, the color and aroma of the beans, and the first and second crack.

How to Roast Coffee Beans at Home? (Video)

In conclusion, home roasting is not as intimidating as you might think. You can have fun while roasting your beans and creating your own flavor.

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