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How to Roast Your Own Coffee Beans At Home

Roasting coffee beans at home is easy and fun. It also saves money and leaves you with a better-tasting morning brew. You don’t even need specialized equipment. So there’s no reason not to give it a try.

Read on for four simple ways to produce freshly roasted coffee beans in your own home. You probably already have everything you need for some of them. Though, we recommend investing in a proper home roaster for the most consistent quality results.

Coffee Beans Roasting

A Short Introduction to Home Coffee Roasting

At its most basic, roasting coffee is heating green coffee beans until they turn brown. However, there are a multitude of subtleties involved. For the best coffee beans, a proper roast must balance the fruity flavors of the green coffee bean with the caramelized flavors of the roast. Moreover, the roasting process can produce up to 1,000 new aroma compounds as it progresses, giving the roast profile significant influence over the taste of your cup of coffee (1)

The Stages of Coffee Roasting

The first stage of the roast is the drying stage when the green beans lose their humidity. Then, the initial phase continues to 320 ℉, at which point the browning stage begins. The result of the browning stage is a toasted aroma. At 385 ℉, the beans will start to pop, and this is known as the first crack. Stop the roast at this point for a light roast. The bean surface will still be dry and light brown, and much of the character of the green bean is still present (2).

The crack is crucial for the flavor. It is also the earliest moment when the coffee can start to actually extract properly.

For medium and medium-dark roasts, continue roasting to between 410 and 460 ℉. The beans will be much darker but still quite dry on the surface. Then, around 440 ℉, coffee beans will undergo a second crack. Here, oils begin to migrate from the inside to the outside of the bean.

This stage marks a dark roast. They will have a shiny, oily surface, a very dark color, and the flavor will be characterized more by the roast than the bean.

Why Roast at Home

Though it sounds complicated, there are many benefits to home roasting (3).

Just like pulling the perfect shot of espresso, coffee roasting comes with its own set of variables to tweak in search of that ideal result.

For one, freshly roasted coffee simply has better flavor, and roasting it yourself allows you to tailor it to your taste. Secondly, it will save you money. Green beans are about half the price of roasted beans (4), and when stored correctly, they have a 3 to 6-month shelf life, allowing you to lower costs even further by buying in bulk (5). Finally, coffee roasting is a craft, and mastering it is fun.

Four Ways to Roast Coffee at Home

No matter how you choose to roast your own coffee, three things must occur for an acceptable result. First, you need to get the beans very hot. Second, for an even roast, you need to keep them always moving. Third, you need to be able to cool them quickly to avoid over roasting.

When choosing home coffee roasting techniques, you should also take into account ventilation and clean-up.

Roasting coffee beans can be very smoky, with some ways being worse than others in this regard. To clarify, as they roast, green beans release a flaky material called chaff that can make a mess of your oven or kitchen if not contained.

There are four commonly used methods to roast coffee at home. You can use your oven or a frying pan, but both of these tend to be messy and smoky affairs. In a similar vein, the stove offers no means of agitating the beans. An upgraded strategy is to use a popcorn popper while being aware that not all popcorn machines can accommodate coffee beans.

The best option, though also the most expensive, is to invest in a home coffee roasting machine (6). If you want to be sure you’re spending your money wisely, we’ve got a list of great machines to choose from.

Purpose-built coffee roasters start at about $250 and quickly climb into the thousands. The good news is that you can begin roasting with equipment you may already own.

No matter which method you choose, you should also be sure to have the best coffee storage container on hand to keep your freshly roasted beans fresh.

Roasted Coffee Beans

How To Roast Coffee Beans at Home

Roasting coffee at home is simpler than you might imagine. If you’ve already bought green beans, you probably have everything you need. Here are four tried and tested methods.

In the oven

The oven may be the most convenient method because nearly everyone already has an oven. Still, it is also the least consistent as it is impossible to keep the beans always moving for an even roast.

What you need

  • Your oven
  • Green coffee beans
  • A perforated oven tray or plain baking sheet with baking paper
  • Metal colander
  • Oven mitts

Step 1: Crank up the heat

Preheat your oven to 500 ℉. Different beans and different ovens will require varying roast temperatures, but this is a good starting point. You can always adjust as the roast progresses.

Pro tip: If your oven has a convection option, don’t be tempted to use it. The fan will blow chaff everywhere.

Step 2: Establish ventilation.

Be prepared for some dangerous smoke. Open your doors and windows as much as possible and turn on every exhaust fan in the area.

Pro tip: The smoke from roasting coffee contains diacetyl, a chemical compound that may cause lung disease when regularly inhaled (7). If you’re aiming for a dark roast, it’s best to work outside or use one of the less smoky roasting methods.

Step 3: Prepare the oven trays.

Spread the beans in a single layer over the perforated tray. Don’t be tempted to cram them in. Get a second tray if necessary. Perforated trays are best because they allow more airflow around the beans. 

If you don’t have a perforated tray, you can use a standard baking sheet with a piece of parchment paper under the beans.

Pro tip: Make sure your perforated tray doesn’t allow any beans to slip through the holes. Beans expand during roasting, and they will get stuck.

Step 4: Start the roast.

Put the oven tray into the center of your oven, where the temperature is most consistent, and let the beans begin to heat. Listen for the first crack, which should occur after 4 to 8 minutes. If you pull the coffee beans out now, you will have a light roast.

Step 5: Continue the roast.

Continue listening for the second crack, which indicates a medium roast. If you wait another 60 seconds to remove the beans, you will have a lovely medium-dark.

Pro tip: Be very careful at this stage, and err on the side of pulling your beans out too early. They can progress from medium to burn very quickly.

Step 6: Cool the beans.

Using the oven mitts, remove the tray(s) from the oven, and pour the beans into a colander. Use two filters if you have a lot of coffee beans to maximize airflow. Shake the colander around to cool the beans. If you can, it’s best to do this step outside. Shaking will facilitate fast cooling and leave you without a mess of chaff to clean up.

Pro tip: Coffee beans will continue roasting from their residual heat. Carry out this step as quickly as possible to avoid over roasting.

Step 7: Let them rest.

Let your roasted beans sit out for at least 12 hours. At this point, they are still off-gassing CO2, and extraction will be negatively affected if you brew during this time (8).

In a pan

Using a pan is nearly as convenient as the oven, provided you have a heavy uncoated pan already at your disposal. Also, it allows you to agitate the beans as the roast progresses. But this method is the most difficult to establish the correct temperature. Plus, it can get very smoky.

What you need

  • Green coffee beans
  • A heavy frying pan, like cast iron or steel
  • A hot plate, gas element, or stovetop burner
  • Colander
  • Oven mitts
  • Wooden spoon

Step 1: Establish ventilation.

Like the oven method, roasting coffee beans in a pan is another smoky option. Using a gas burner outside is the best way. Still, if you have to be indoors, open your doors and windows and turn your exhaust fans to max.

Step 2: Turn on the heat

Turn your burner to medium-high. Coffee roasting temperature control is more difficult with a heater than an oven, so be prepared to adjust the heat as your roast progresses. Also, expect that your first few batches may not be perfect.

Step 3: Begin the roast

Add your green beans to the pan, and begin stirring them with the wooden spoon. Keep stirring as the roast continues. The more the coffee beans are moving, the move even the roast will be.

Pro tip: Don’t crowd the pan with beans, or they won’t be able to heat evenly. Aim for a single dense layer.

Step 4: Roast with your ears

In a full pan of continually moving beans, you don’t want to rely on your eyes to gauge the progression of the roast. Listen for the first crack, which should occur after 4 to 8 minutes. If you stop now, you will have a light roast. For a medium to dark roast, continue listening for the second crack. Remove the beans from the heat right away for a medium roast or wait another minute or two for medium-dark or dark.

Pro tip: Be careful not to wait too long. It’s possible to over-roast the beans at this stage. Especially because they will continue to roast after being removed from the heat.

Step 5: Cool the beans

Using the oven mitts, pour the beans from the pan into a colander. Shake the colander around to cool the beans as quickly as possible, so they don’t over-roast. If you can, it’s best to do this step outside. Like with other methods, shaking will facilitate fast cooling and leave you without a mess of chaff to clean up.

Step 6: Let them rest

Let your roasted beans sit out for at least 12 hours to finish off-gassing CO2.

With a popcorn maker

Most home roasters will first experiment with a popcorn popper. They offer a lot of the same functionality as a coffee roaster at a much lower price. Just be aware that popcorn machines cannot accommodate heavy coffee beans, and you can damage them in the process.

What you need

  • Green coffee beans
  • Popcorn machine with side-vented heat
  • Wooden spoon
  • Colander
  • Oven mitts

Step 1: Establish ventilation.

The popcorn machine will be less smoky than the oven or pan, but you should still open your doors and windows and turn your exhaust fans to max.

Step 2: Preheat the popcorn machine.

Depending on the model, it will take about a minute to get your popcorn machine ready to go.

Pro tip: You must use a side vented popcorn machine to ensure rotation and avoid burning your beans.

Step 3: Begin the roast.

Add the beans to the machine, using the same quantity the manufacturer recommends for popcorn. They should begin to agitate. You can assist this stage by stirring them around with the wooden spoon to get them moving. Once the beans are moving consistently, place the lid on the machine and monitor the roast.

Pro tip: If you can’t get the beans moving, you have probably added too many.

Step 4: Roast the beans.

Listen for the first crack, which should occur after 4 to 8 minutes. Turn off the machine now for a light roast. For a medium to dark roast, continue listening for the second crack. Stop the roast right away for a medium roast or wait another minute or two for medium-dark or dark.

Step 5: Cool the beans.

Using the oven mitts, pour the beans into a colander. Shake the colander around to cool the beans as quickly as possible, so they don’t over-roast. If you can, it is best to do this step outside. Shaking will facilitate fast cooling and leave you without a mess of chaff to clean up.

Step 6: Let them rest.

Let your roasted beans sit out for at least 12 hours to finish off-gassing CO2.

With a coffee roasting machine

A home coffee roaster is undeniably the best way to roast coffee beans at home. Though they are more expensive, they will last much longer than a repurposed popcorn machine. Most importantly, the quality of the roast is far superior to the other methods. So, if you plan to roast your beans regularly, it’s a worthwhile investment.

What you need

  • Green coffee beans
  • A coffee roasting machine
  • Oven mitts (optional)
  • Colander (optional)

Step 1: Establish ventilation.

Dedicated home coffee roasters often feature smoke suppression systems. Still, you should make an effort to maximize ventilation or do your roasting outside.

Step 2: Ready the machine.

All coffee roasters are different, so you should follow the manufacturer’s instructions for this step. For electric roasters, power them on and add the beans. For roasters that use a gas burner, start the heater and allow them to heat up, then add the beans.

Step 3: Roast the beans.

Many home coffee roasters claim to be fully automated, but you should still monitor the roast carefully. Watch the darkening color of the beans, and listen for the first and second crack. 

Pro tip: Some roasters allow you to adjust temperature and fan speed as the roast progresses. Others feature a probe so you can sample beans during the roast. Use these to optimize your roast.

Step 4: Cool the beans.

A good home roaster typically offers a built-in cooling system. If this is the case, simply turn it on. If your roaster doesn’t have this feature, you can use a colander the same way as the other roasting methods.

Using oven mitts, pour the beans into a colander. Shake the colander around to cool the beans as quickly as possible, so they don’t over-roast. If you can, it is best to do this step outside. This will facilitate fast cooling and leave you without a mess of chaff to clean up.

Step 5: Let them rest.

Let your roasted beans sit out for at least 12 hours to finish off-gassing CO2.

via GIPHY

Final Thoughts

If you’re enthusiastic about coffee, roasting your coffee beans at home is a no-brainer. It’s fun, it saves you money, and most importantly, it results in fresher, better-tasting coffee. With this article, you now have all the information to know how to roast coffee beans at home. Even if you only have essential kitchen equipment.

If you plan to be a regular roaster, though, we strongly recommend you invest in a home coffee roaster, which will produce perfectly roasted beans for years to come.

FAQs

It takes about 10 to 15 minutes to roast coffee beans. The time period depends on the type of green beans, the darkness of the roast, and the method of roasting.

No, you do not need to wash green coffee beans before you roast them. However, this is yet another roast variable to experiment with if you wish.

Yes, coffee beans need to be roasted. Roasting breaks down the outer structure of the bean, which is what permits proper extraction when brewing.

References
  1. Latvakangas, S. (2017, May 30). Coffee Roasting Basics: Developing Flavour by Roasting. Retrieved from https://www.baristainstitute.com/blog/sampo-latvakangas/may-2017/coffee-roasting-basics-developing-flavour-roasting
  2. Nieminen, T. (2017, January 6). Coffee Roasting at Home: A Stupid Idea or a Culinary Adventure. Retrieved from https://www.baristainstitute.com/blog/tomi-nieminen/june-2017/coffee-roasting-home-stupid-idea-or-culinary-adventure
  3. Cho, N. (2018, August 9). Should You Roast Coffee at Home? Retrieved from https://drinks.seriouseats.com/2013/12/why-you-shouldnt-roast-coffee-at-home-pros-cons-green-coffee-roasting-kit.html
  4. Albrecht, I. (2018, August 22). A Home Roaster’s Guide to Buying the Right Green Coffee. Retrieved from https://perfectdailygrind.com/2018/08/a-home-roasters-guide-to-buying-the-right-green-coffee/
  5. Guerra, G. (2017, November 6). Green Bean Storage: What Factors Do You Need to Control? Retrieved from https://perfectdailygrind.com/2017/11/green-bean-storage-what-factors-do-you-need-to-control/
  6. Shilton, AC. (2020, February 8). We Tried Roasting Our Own Coffee. Learn From Us. Retrieved from https://www.outsideonline.com/2408826/roast-your-own-coffee
  7. Bailey, R.; LeBouf, R. F.; Cummings, K. J. (2016, January 25). Coffee Workers at Risk for Lung Disease. Retrieved from https://blogs.cdc.gov/niosh-science-blog/2016/01/25/coffee-workers/
  8. McPhee, H. (2018, March 29). Understanding Degassing: Is Fresh Best? Retrieved from https://fellowproducts.com/blogs/learn/understanding-degassing-is-fresh-best
How to Roast Coffee Beans

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