Most people have never seen raw coffee beans unless they've gone through the process of roasting them at home.
During the roasting process, the coffee beans go through several chemical changes — dramatically altering the flavor and turning them from light green to brown.
The roast level is determined by the amount of time the beans are roasted — from light, medium, medium-dark, dark, or full-french roast.
In this article, we'll walk you through the whole process of roasting your own green coffee beans at home from start to finish.
What to Consider Before Roasting Coffee Beans at Home
There are five important details you need to consider before you roast coffee beans:
- Ventilation — Ensure you are in a well-ventilated area. Roasting coffee can create smoke, so open a window or use an extractor fan.
- Desired Roast Level — Determine whether you want light, medium, or dark-roasted beans before you begin, and watch the beans carefully to time your roasting level accordingly. We will include more about how to do this in the next section.
- Chaff — This is the messy husk of the coffee bean that is produced during the roasting process. To remove this, place your roasted beans in a colander and shake it out.
- Plan Ahead — After roasting, coffee beans need to rest for between 12–24 hours before you can enjoy them. This is to ensure full development of the aroma and flavors.
- Storage — Keep roasted coffee beans in an airtight container away from heat sources and direct sunlight. The coffee beans will remain fresh for a month but are best enjoyed within the first week.
Roasting Coffee: What You Need
You don't need any special equipment to roast coffee beans at home other than raw green coffee beans, which are widely available online.
There are three tried and tested methods of roasting fresh coffee beans in your kitchen without having to buy expensive equipment.
You can roast them in a pan, an oven, or a popcorn maker.
Here's how to do it…
1. Pan Roasting Coffee Beans
This may seem like the easiest method because you only need a pan, but a successful pan roast is reliant on consistent overall heat and using the right quantity of beans.
Too many, and you won’t get an even roast.
This method takes approximately 5-10 minutes.
What You’ll Need (Ingredients & Tools)
- ½ cup of high-quality green coffee beans
- A cast iron pan
- Stove (electric or gas both work)
- Wooden spoon or spatula
- Thermometer (optional)
- Metal Colander
Step 1: Preheat the Pan
Place your pan on medium heat and let it warm up to between 350-500ºF or 177-260ºC.
A spot of adjustment might be required to maintain consistent heat and stop the pan from becoming much hotter than this, but practice makes perfect.
Step 2: Add the Raw Coffee Beans
The size of your pan dictates the amount of coffee beans you need.
Two heaped tablespoons of coffee beans should be sufficient to yield one cup of coffee made with 6 oz of water.
It is important to be able to stir the beans easily and ensure they are getting evenly distributed heat.
Step 3: Keep Stirring, Watch for Changes, & Listen for Cracks
You need to stir the beans continually and watch for color changes.
Your coffee beans will gradually change from green to yellow before they finally turn brown as the moisture inside the beans gradually starts to evaporate.
You may begin to notice a fragrant scent coming off the beans as they change:
- When you hear the first crack, you have light-roasted beans, and you can stop the roasting process at any point afterward.
- You will have medium-roast beans if you continue to roast them for an additional minute, during which time you might notice the aroma of the beans getting sweeter.
- If you continue to roast the beans, you’ll hear the second crack to reach a dark roast level, during which the smoke may become more sour and powerful.
Step 4: Let The Beans Cool & Rest For 24 Hours
Once you’re happy with your roasting level, allow your beans to cool down completely by placing them in the colander.
Please note that the coffee beans will continue to roast after you’ve removed them from the heat, so you may need to adjust your roasting time accordingly. Shake off the chaff and continue to stir the beans to cool them down.
Let them rest for 24 hours in an open container with no lid to ensure all the carbon dioxide escapes.
Step 5: Store in an Airtight Container in a Cool, Dark Location
Now that you’ve completed the first four steps, you can grind your beans, brew your coffee, and enjoy.
Store any remaining beans in an airtight container away from sunlight and heat.
Enjoy them fresh for up to a month after roasting.
2. Oven Roasting Coffee Beans
Although oven-roasting coffee beans is fairly straightforward, it’s a bit fiddly, as you have to keep opening the oven door, stirring them, and checking on them.
Opening the oven door repeatedly can generate a lot of smoke and might set off your smoke detectors.
However, in comparison to pan roasting, the benefit of oven roasting is that you can guarantee that your oven is set to the right temperature from the beginning, and it will allow you to get even roasting results in 5-10 minutes.
The oven roasting process is very similar to the process for pan roasting.
What You’ll Need (Ingredients & Tools)
- ½ cup of high-quality green coffee beans
- A baking tray
- Oven
- Wooden spoon or spatula
- Metal Colander
Step 1: Preheat the Oven
Preheat your oven to 500ºF or 260ºC.
Step 2: Place Raw Coffee Beans on Baking Tray
Spread half a cup of green coffee beans evenly on a baking tray and place them in the oven.
Step 3: Stir Raw Beans, Look for Changes, & Listen Closely for Cracks
To see the color changes and ensure you don't miss the cracks and overroast your beans, you need to check on them every 1-2 minutes, taking them out of the oven and stirring them.
Pay attention to color changes and listen very carefully to make sure you don’t miss the cracks.
When you have the desired roast, remove the beans from the oven and repeat steps 4 and 5 from the pan roasting process above.
3. Roasting Coffee Beans in a Popcorn Popper
Roasting coffee beans with an old-fashioned stovetop popcorn popper may not seem like an obvious choice, but you can still achieve excellent results utilizing this method.
Similar to oven roasting, this method may generate a lot of smoke.
If you don't have adequate ventilation, including an extractor fan or an open window, you should only try this method outside on a camping stove, campfire, or barbecue.
What You’ll Need (Ingredients & Tools)
- ½ cup of high-quality green coffee beans
- Stovetop popcorn popper
- Stove (electric, gas, or camping)
- Thermometer (optional)
- Metal Colander
Step 1: Preheat the Stove
Choose a low–medium heat to preheat your popcorn popper.
This is easier on gas stoves as you can adjust the temperature quickly, but it will work on an electric stovetop, too.
You can check the temperature with a thermometer for accuracy, but it is not a requirement.
The popper should be preheated to 45ªF or 232ºC.
Step 2: Pour the Raw Coffee Beans into the Popcorn Popper
Pour half a cup of green coffee beans into the popcorn popper and stir the pot to evenly distribute the beans across the bottom.
When you’ve done this, the interior temperature will have dropped to around 300ºF or 150ºC.
Step 3: Roast Your Beans, Listening Intently For Cracks
Close the lid of the popcorn popper and turn the crank. Ensure you maintain a consistent pace to ensure the beans keep moving freely. This will prevent them from burning and keep the roast even.
Try to resist the temptation to open the lid too much, as you want to maintain the temperature inside.
Listen closely to the popper to make sure you hear the cracks.
Remember that the beans will continue to roast while they are still hot. When you are satisfied with the roast level, remove the beans from the heat and repeat steps 4 and 5 from the pan roasting section above.
Buy Pre-Roasted, Premium Coffee Beans
Love the idea of freshly roasted beans but don’t have time to roast your own at home?
Why not purchase some premium-quality coffee from Cafely?
Choose from instant, ground, and whole bean coffee, safe in the knowledge that you will be enjoying an exceptional cup of coffee every time.
FAQs: Roasting Coffee Beans
Still have some questions? Read our FAQ section to learn how to avoid roasting mistakes.
1. Can I Grind Coffee Beans as Soon as They Are Roasted?
No. We know it’s tempting, but the cooling and resting phase is crucial if you want the perfect flavored cup with a satisfying aroma.
Letting the beans rest for 24 hours ensures all the carbon dioxide and carbon monoxide gas have been released. If not, the gases can cause uneven flavor extraction during the brewing process. Trust us and be patient. It’ll be worth the wait.
2. Where Can I Buy Green Coffee Beans?
Green coffee beans are typically sold in wholesale quantities, and you won't need that many if you are roasting a small batch at home. However, they are becoming more widely available in smaller quantities online. Retailers such as Amazon now offer them in 500g-1kg bags.
Related: Where to Buy Authentic Vietnamese Coffee?
3. Why Should I Roast My Coffee Beans at Home?
Roasting your own coffee beans gives you the control to ensure they are at peak freshness when you grind and brew them. It also ensures you're always getting the freshest, most flavorful coffee possible.
Related: Butter Roast Coffee
4. My Roast Was Uneven. What Am I Doing Wrong?
It depends on which method you're using, but it could be that you are using too many beans.
Start small until you get a feel for home-roasting methods. Less is more and will ensure that all your beans absorb the heat properly and evenly.
If you aren't using a popcorn popper, make sure you stir the beans to ensure they move freely. This will prevent them from getting burnt.
Finally, ensure you are roasting the beans at the correct temperature for whatever method you are using, and keep a close eye on them.
5. Do I Have to Preheat My Pan or Oven Prior to Roasting?
Proper preheating is crucial to the success of your roast. Consistency of heat is vital to ensure an even distribution. If you’ve ever attempted to cook a pizza in a cold oven and experienced the joy of scraping it off the shelves once it collapsed, you might have an understanding of how important the preheating stage is.
You don't want under or over-roasted coffee beans, so don't skip the warm-up.
References
- Bolka, M., & Emire, S. (2020). Effects of coffee roasting technologies on cup quality and bioactive compounds of specialty coffee beans. Food Sci Nutr. 8;8(11):6120–6130. doi: 10.1002/fsn3.1904. PMID: 33282263; PMCID: PMC7684626.
