Roasting your own coffee at home is very rewarding. You'll get the freshest possible coffee and learn heaps about the green coffee bean in the process. You'll learn which beans are great for what type of roast, either via experimenting or reading up on it, and you'll learn more about what different roast levels actually mean.
You may wonder: Isn't the machinery you need to roast coffee expensive? Not necessarily! If you go for a professional drum roaster, you'll pay a certain price, but if you are new to roasting coffee and aren't sure whether you'll stick to it, a popcorn popper is a good way to dip your toes into the world of home roasting.
This article will give you all the information you need to start your coffee roaster journey, full of enticing aromas and delicious cups of coffee.
Important Note: While roasting with a popcorn popper is a relatively affordable way to start roasting, it should not be considered a long-term solution. Most poppers will stop working after 4-6 months of regular use because roasting green beans puts much more stress on the machine than popping popcorn. You won't be able to claim any warranty or guarantee on it either because roasting anything but popcorn in a popcorn machine immediately voids the warranty.
Getting Started: What You Need To Roast Coffee Beans in a Popcorn Popper
Of course, you’ll need a popcorn popper (more about choosing the right one below), but in addition to the actual machine, you’ll also need:
A bowl for catching the chaff that comes off the roasted beans
A big, long-handled spoon to stir the beans (wooden is best)
At least one metal colander for cooling the freshly roasted beans
Oven mitts (or something similar to protect your hand)
A fire extinguisher or bucket of water (in the rare case of something catching fire - which usually only happens if you leave the roasting coffee beans unattended)
Optional:
Digital scale
Candy thermometer
Choosing the Right Popcorn Popper
There are dozens of poppers on the market, and not each is suitable for home roasting. The first important thing you must check is that the machine you want to buy has air vents on the chamber's SIDE, not at the bottom. Bottom vents won't work for roasting coffee. In addition, the popping chamber must be made from metal.
To make your decision a little easier, here are some examples of popcorn machines that work well for roasting coffee:
If you happen to come across a West Bend Poppery 1 (1500 Watts) or a West Bend Poppery II (1200 watt model) in a thrift store, at a car boot sale, on eBay, or other secondhand markets, these machines would be great options, as long as they're in a very good condition. Don't buy used popcorn poppers if you suspect they've already been used to roast coffee.
The newer West Bend Air Crazy (make sure to get the model with the side vents) is also a good alternative and still easy to find new and unused.
Sourcing Green Coffee Beans
Of course, you won't get far on your coffee-roasting journey without coffee beans! As you'll only roast small batches in your popcorn popper, we recommend investing in good-quality coffee beans - you won't regret it.
Coffee Bean Selection
Selecting the best beans can seem a tad overwhelming when you're new to roasting your own coffee. There are so many options out there. On one hand, that's awesome; on the other hand, it's hard to know which green beans would turn into the perfect cup of coffee. Here are some pointers to help you with your selection.
Think about which flavor profile you prefer. If you know which flavor notes you love in coffee, then that's a good place to start. Coffee beans from different regions have distinct flavor characteristics, so you must familiarize yourself with which country produces what coffee. The origin country should be one of your first considerations.
For example, African coffees are loved by people who enjoy coffees with bright acidity and floral or fruity notes. Central and South American beans are more popular with people who enjoy a more balanced cup with nutty or chocolatey flavors.
When doing your coffee origin research, you'll also notice many different coffee varietals like Bourbon, Typica, Geisha, and SL28, to name a few. These also influence what coffee tastes like.
Next, you should check the processing methods as they influence a bean's taste and behavior during roasting. This is because the different processing methods lead to variations in moisture content and bean structure.
Which Processing Method is Best for Roasting Beginners?
Generally speaking, washed coffee beans and pulped natural beans are the easiest to roast for beginners because they have a relatively uniform moisture content. Honey-processed beans can be a little more challenging because of their varying moisture levels. You probably should have some roasting experience before you try these.
Beans processed via the natural process are also a bit different. They often have high moisture content, and there is a potential for uneven roasting. These beans are also better for roasters with some experience. Last, we have semi-washed or wet-hulled beans (which often come from Sumatra). Don't try roasting these as a beginner, as they can be challenging because it's easy to over-roast or scorch them.
Storing Green Coffee Beans
You'll likely buy more than you'll use right away, so it's important to know how to store the rest of your beans properly.
The best containers are airtight because keeping your coffee away from oxygen is important. You can use mason jars and vacuum-sealed bags or invest in specially designed coffee storage bags. It would be best to store beans in a cool and dry place. Keep them away from direct sunlight and other heat sources. The best temperature to store your own beans is 60°F (15°C), but a few degrees below or above are still fine, too. Don’t freeze green beans.
Also, remember that coffee beans can absorb odors from things around them, so don't store them next to strong-smelling stuff like chemicals or pungent foods.
Write the age of your coffee beans on the container, and always use your oldest stock first.
Preparing Your Workspace
You must set your hot air popcorn popper up in a well-ventilated area. There'll be some smoke during the process, and you'll need to ensure this doesn't cause an issue. Set your popcorn popper close to an open window or extraction fan.
It's also best to have a light source close to your popcorn popper: Either natural light from a window or an artificial light source, as you'll need to be able to look into the popping chamber. It's important to always keep an eye on what's happening to your coffee beans; you don't want your beans to turn into charcoal. Charcoal coffee doesn't taste nice, and over-roasting beans is a fire hazard.
Ensure you have everything you need close by, like the colander(s), oven mitt, spoon, etc.
The Roasting Process
How Much Coffee Can You Roast in A Popcorn Popper?
While one hot air popper can be different from another, especially when you include vintage options, most of them can roast around 85g of green coffee in one go. This would equal around 70g of roasted coffee as green coffee beans lose moisture during roasting. 70g of coffee is enough to brew about 8 cups of coffee.
You can theoretically roast a few batches of coffee straight after each other, but we don’t recommend this as it will significantly shorten the lifespan of your popcorn popper.
If you aren't sure how much you can roast in your popper, try this: After preheating your popper, add in green coffee beans until the popper is just moving them around. If you put in so many beans that they stop moving, you've put in too much coffee.
Steps of Roasting Coffee in a Popcorn Popper
Only start this process when you're almost 100% sure you can focus on the task. Put aside about half an hour. If you want a nice roast, you must dedicate your full attention to this.
Measure the beans: As mentioned above, you usually want to use around 85g, but this amount can differ from machine to machine.
Preheat the popcorn popper: After making sure that the popper is clean and free of any residue from previous uses, plug it in and let it preheat for a bit.
Add the beans: Pour the measured green coffee beans into the preheated popper (or use the above method to determine how many beans you can add). Remember: From that point on, it's vital that you keep an eye on what's happening to the beans. If the beans don’t move properly, stir them manually until they’ve lost enough moisture to move freely on their own.
Begin roasting and listening: As the beans roast, they undergo several stages. You'll notice distinctive cracking sounds after a few minutes (times vary from popper to popper). Suitably enough, the first crack will remind you of popcorn popping. This first crack signifies that the beans are now at the light roast stage. You'll work on a medium roast if you keep roasting after the first crack. And if you continue roasting after the second crack (which is a duller sound), you'll work towards dark roasts. Be attentive, as the beans can quickly go from a medium to a dark - and then to charcoal. Tip: Check other articles in our blog to learn more about topics like roast time and the roast level.
Monitor the roast at all times: In addition to listening, you also need to observe the color of the beans as they roast. A light roast is pale brown, while a medium one is medium brown. For a darker roast, the beans will become dark brown, approaching black. Remember that the timing of these stages will depend on the popper and bean type.
Cooling: As soon as they reach the roast level you aim for, you need to cool them immediately. The easiest way to do this is to carefully transfer them to a metal colander and shake them - or use two colanders and move the coffee from one colander to the other. During that process, the remaining chaff will come off. You can also use a cooling fan if you'd rather put them on a baking sheet - but beware of flying chaff!
Resting and Storing: After cooling the freshly roasted coffee, let it rest for at least 12-24 hours to allow the flavors to develop. Store it in an airtight container, preferably one specifically designed for storing coffee, away from light, moisture, and oxygen.
How to Solve Hot Air Popper Problems
Problem: Uneven Roast / Lack of Bean Movement
Solution: Popcorn poppers are not designed for coffee roasting, so beans can get stuck or not move properly. This leads to an uneven roast, a common issue with popcorn poppers. To get an even roast, stir them manually during roasting (a wooden spoon is best).
Problem: Overheating
Solution: Popcorn poppers can overheat easily when roasting coffee. To prevent this, roast in a well-ventilated area and use an extension cord (this will slow the machine down a little). If you have the opposite problem and the machine doesn't heat enough, remove any extension cord and plug the popper in directly.
Problem: Inconsistent Roast Profiles
Solution: It's not easy to achieve precise roast profiles with a popcorn popper. That's why you need to be willing to experiment with the roast time and temperature to find the right combination. Keep detailed notes for each batch so you can always refer back and check what worked and what didn't.
Problem: Smoke and Chaff
Solution: Coffee roasting produces smoke and chaff. Popcorn poppers do not have a built-in smoke suppression system. As mentioned, you must roast in a well-ventilated area or under an extraction fan. Chaff will be flying around, so roasting outdoors is always an option. You could also place the popper in a huge box, which would catch the falling chaff.
Conclusion
Roasting coffee beans in a popcorn popper has challenges, but it's a cheap way to start. Remember to set up your workspace with good ventilation and ample light, and pay attention during the roasting process to avoid over-roasting.
If you keep practicing, you'll overcome common issues like uneven roasting, overheating, and inconsistent roast profiles. Home-roasted coffee from a popcorn popper is the first step on your home-roasting journey.
