DIY Home Coffee Roasting

by Tyron | Last Updated: February 26, 2021

DIY Home Coffee Roasting

“Black as the devil, hot as hell, pure as an angel, sweet as love.” 

Indeed, Charles Maurice de Talleyrand-Périgord knew good coffee and over 300 years later we are still captivated by the mystic powers of the humble coffee bean. 

In fact, DIY home coffee roasting has become a popular pastime for those who are curious about the alchemy behind the fickle personality of the coffee bean, giving rise to a whole industry of budding baristas. 

As a fellow coffee-lover, you’re certain to want to understand more about these magic beans and how you can create your own uniquely flavourful beverage at home. Thankfully, science is easier than you may have originally thought. 

The Roasting Process

How do we turn a somewhat unappetizing little greenish bean into a rich, steaming cup of pure pleasure? 

The process is complex and thrilling; sort of like a 15-minute soap opera where all the excitement is locked within these enigmatic little nubs of nature. Externally, it looks something like this: 

Yellowing

The first stage of roasting will take your green beans with a definite vegetable-like taste and smell and turn them into a light yellow shade. You will notice that they will start to steam a little as they begin to dehydrate in the heat. 

Browning

Also known as the Maillard reaction, your beans will start to darken as critical chemical reactions within them begin. Interestingly, this same process brings out the delicious flavours of other foods such as chocolate and grilled steak. 

Caramelization

Hot on the heels of the browning process comes caramelization, where the natural sugars in the coffee beans begin to react to the heat and give off that heavenly caramel-like aroma. 

First crack

As the sugar within the beans caramelizes, the bean physically cracks internally with a discernable popping sound. Residual moisture and delicious oils are released as the bean structure starts to break down. 

Theoretically, your roast is now considered ready and you can remove it and enjoy a smooth, light brew. However, some prefer to leave the beans in a little longer, tempting fate and experimenting with varying flavours. 

Second crack

Further roasting results in a darker bean until you reach the second crack – another audible cue that you’ve reached the grand finale of your coffee roasting exercise. 

Of course, these steps are a high-level guide to the complex roasting process. You may find that your perfect cuppa is somewhere between first and second crack, and a little experimentation with various beans and roasting profiles will further hone your brew. 

Roasting profiles

Besides the origin of the bean and the anticipated extraction method, the roasting profile will determine the final taste and characteristics of your coffee. 

The roasting profile consists of temperature and temperature rise, roasting time, and reduction time. It’s worth taking careful notes while you’re experimenting with the roasting process, as a minute here and a few degrees there can completely change the final taste of your coffee. Some say that the perfect roast is timed to the second!

So now that we know what the process looks like, what happens next?

Coffee Roasting Equipment

When you’ve been lured into a coffee house by the tantalizing aroma of freshly roasted beans and you scan the equipment behind the counter responsible for this delicious odour, you can be forgiven for thinking that you need a doctorate and specialised equipment to roast your own coffee at home. 

(Coffee roasting equipment is like the automobile industry; you can get a Mercedes, or you can get a VW Beetle – both will get you to your destination.)

Don’t be fooled by unemployed Millennials with over-inflated egos and man buns who insist that coffee roasting is best left to the professionals…dude. 

To get started, all you need a heat source and a little patience.

That’s it. 

Oven-roasted coffee

If you’re roasting your own beans for the first time, then you may want to try oven roasting. The great thing about this method is that you have greater control over the temperature which, as we mentioned, is a key component in the final taste of your coffee.

Heat your oven to 250˚C and lay your beans out evenly on a baking sheet. 

Don’t go anywhere! 

You’ll need to open the oven every couple of minutes to agitate the pan and ensure that the beans are roasting evenly. After around five minutes you’ll hear the first crack and will smell that familiar mouthwateringly divine smell as your beans start to turn brown. 

Once they have reached the desired intensity, remove the tray from the oven and place the beans into a colander or other perforated vessel. Gently shake them in a breezy spot (perhaps in front of a fan) to get rid of the chaff and to cool them quickly to prevent the sugars from continuing the cooking process. 

Skillet or pan-roasted coffee

Another simple but effective way of home roasting your own coffee is to use a pan on the stovetop. (A gas stove is perfect for this purpose as it heats the pan quickly and evenly.)

In this instance, you’ll want to pour your green beans into a hot skillet and cover while set over medium heat. Be sure to shake the pan around every minute or so to ensure the even distribution of heat and check on the colour frequently. 

Somewhere between the first and second crack, you’ll remove the pan from the heat and again, place your beans in a place where they can cool quickly.  

Popcorn popper coffee

A popcorn maker is a perfect vessel to home roast your coffee. Another stove-top method, a popcorn maker has the added benefit of that little stirring mechanism which helps to move the coffee beans around for even heating.  

You may find that you prefer oven roasting to stove-top roasting as the beans can release a lot of steam as they heat up. (This may be why some of the more adventurous souls love to roast their beans over a campfire while out in the mountains and experience the warm, pungent steam swirling in the open air.)

Whatever roasting method you’ve chosen, remember to remove your beans from the heat just before they achieve the depth of colour that you want. The oils and sugars in the bean are super-hot and will continue the roasting process until they have cooled.

Place your cold beans in a cool, dark place for around 48 hours to allow them to release the remaining CO2 and then store them in an airtight container until you’re ready for your perfect cup.

Gene Café Roaster

Gene Coffee Roaster

What if you’ve tried roasting your own beans a few times and you’re ready to take your barista capabilities to the next level? 

One of the most popular products for home roasting enthusiasts is the Gene Café CBR 101 Home Coffee Roaster. This sleek and compact coffee roaster is a perfect choice if you’ve found that you’re loving DIY coffee, but would prefer a more consistent result. 

With a 4-star review, this little bit of kit promises to deliver a constant supply of delicious coffee beans roasted to perfection. The Gene Café is pretty simple to set up although there have been some gripes about the quality of the Korean-English translation in the manual. 

This all-in-one roaster really works well to take away many of the fiddly elements of home roasting. Temperature and timing are easily and accurately set to ensure that your brew turns out exactly as you expect. 

As the drum rotates and beans jumble around each other, a handy little vent scoops up the chaff and squirrels it away for easy removal.

The clear upper allows you to keep a close eye on your beans as they move around the drum, making use of hot air to coax out the flavours you’re eagerly anticipating. Once you’ve reached your desired colour, you simply set your roaster to cool and the fan quickly reduces the drum temperature and cools your beans. 

Coffee Roasting Kit

Whatever route you decide to go with your DIY home coffee experience, there will be certain essentials that you need to add to your kitchen. 

Here’s a quick guide to get you started:

Preparation

Green beans – obviously.

A colander or other perforated vessel for cooling.

A scale to measure your green beans accurately.

Roasting

For stovetop roasting, you’ll need a wide, heavy-bottomed pan or skillet. Alternatively, a popcorn pot will do nicely. If you’re oven roasting, then you’ll need a large flat baking tray. (A cookie tray will do nicely.)

After roasting

Storage jars or resealable plastic bags to store your roasted coffee in.

A logbook. Keeping careful notes of your roasting processes will help you to hone your skills. 

A coffee bean grinder.

Additional

A coffee roasting book. There are many of these available online, some of which offer really useful resources such as a colour sample chart to help you check where your beans are in their roasting process. 

In Conclusion

DIY home coffee roasting is one of those rare pleasures in life which combines a fascinating hobby with one of life’s greatest indulgences: the perfect cup of coffee. 

It’s perfect for impressing your friends with your new-found skill, or simply for crafting the perfect cup of dark, smokey excellence.