So, you’ve been stepping up your barista game at home? First, you bought a Chemex in order to make better brews. Then, a burr grinder to have a wider range of unground options! But you’re still having to buy roasted beans, right? No longer! We’ve put together a comprehensive guide so that you can learn how to roast coffee at home.
Why Do You Need To Roast Coffee?
Roasted coffee doesn’t just grow on trees! Okay, we get it, that’s pretty obvious. The roast coffee that we know and love starts its life as a small red fruit that grows on the coffee tree (or small shrub) that grows in tropical regions.
The first step in processing this fruit is to remove the outer red skin, pulp, and inner parchment skin. The remainder of the fruit is a wet, green coffee bean. After this, the green coffee bean is dried.
Once dried, the green coffee bean can be stored for months at a time, much longer than roasted beans, without going bad!
What would happen if you didn’t roast green coffee beans? If you grind up green coffee beans, the resulting cup would be extremely bitter and very acidic. The roasting process dries out the bean and extracts the nuanced flavors of the bean.
What Happens When You Roast Coffee?
When you roast green coffee beans, the beans undergo a chemical change. Aside from heating and drawing water from the bean, the roasting process releases over 800 chemical compounds, about a third of which are aromatic!
This explains the stark difference between the smell and the flavor of green coffee beans and roasted beans.
In simple terms, the sugars within the bean are caramelized, releasing C02 as they “degas”. This is the process that gives beans of different origins, climates, and soils such different flavors! It is important to let the beans breath even after roasting is complete, because the beans will continue to degas two weeks or more after roasting.
As the beans are heated, they lose about one fifth of their weight (from evaporated water) while getting 50-100% larger in size! You’ll notice that green coffee beans feel more dense than their roasted counterparts, now you know why!
The 16 Stages Of Roasting Coffee Beans
Professional coffee roasters and chemists have identified the eleven key stages that even green coffee bean follows! Take note here, you’ll have to identify them as you’re roasting your own coffee beans at home. We’ve included a picture of what each stage looks like, all credit goes to Sweet Maria.
- Green (up to 75°F) – As the beans begin to heat, they maintain the same look at room temperature green coffee beans. If you’re looking to roast green coffee beans, this is where you’ll start.
- Pale (75-270°F) – As the beans heat further, they turn from green to pale yellow. It can take a bit of time to reach this stage, especially if you’re not using an air roaster. The boiling temperature of water is just over 200°F, so you’ll start to see steam as the color begins to change!
- Pale/Yellow (270-325°F) – The coffee continues to lose water, but the bean still doesn’t expand at this stage.
- Yellow/Tan (325-345°F) – Once your beans start to turn darker yellow-tan, you’ll notice the smell of roast coffee for the first time.
- Light Brown (345-370°F) – You’ll start to see the crack in the middle of the bean start to expand.
- Brown (370-390°F) – The coffee now quickly turns brown due to the caramelizing of sugars within the bean.
- First Crack Begins (390-400°F) – This is the first significant stage of the roasting process. You’ll hear a few pops, similar to the sound that popcorn makes as it’s being heated.
- First Crack Continues (400-415°F) – As the internal bean temperature continues to rise, pops continue at an increasing rate. At this point, you’ll also notice that the beans are bigger than green coffee beans — this is caused by a combination of the release of steam and the reaction of the heated sugars within the bean.
- City Roast (415-425°F) – This is the first stage of the roasting process that yields a coffee bean that can be ground up and brewed!
- City Plus Roast (425-435°F) – First crack has completely finished and the roasting process appears more even across the bean. If you’re roasting your own coffee at home and are looking for a lighter roast, now is the time to finish the roast!
- Full City Roast (435-445°F) – This is a bit darker than the City Roast and the bean is quickly approaching the second crack.
- Second Crack Begins (445-455°F) – You’ll start to hear the first few pops of the second crack, notice that they’re louder than the first crack. This roast is a bit fuller than the Full City Roast. This is also the last stage where the tasting notes of the origin are more prominent than the roast character — the flavors that come from the temperature that the beans are roasted to.
- Light French Roast (455-465°F) – As the beans continue to heat, they lose more and more of the origin flavors. If you’re buying expensive beans for the distinct notes of their region or origin, anything beyond this stage will negate those delicate flavors!
- Full French Roast (465-475°F) – At this point, the sugars within the beans are heavily caramelized and degraded. If you’ve ever had cheap donut shop coffee that tastes burnt, there is a good chance you’re drinking a Full French Roast.
- Full Carbonized (475-485°F) – As you’ll notice, the a mere 20°F change from the beginning of the second crack greatly darkens the bean. At this point, the coffee is over 25% ash.
- Fire! (485°F +) – At this point, the beans are at risk of catching on fire imminently.
After you’ve roasted the beans to the desired temperature, you’ll need to remove the chaff — or outer husk — of the bean. During the roasting process and during the first crake, the chaff separates from the bean. Basically, you’ll need to sift the beans. The easiest way to do this is to take two colanders, or anything with holes smaller than the roasted beans, and toss the beans back and forth between them.
It’s okay if some chaff remains, it won’t affect the taste of your coffee too much!
What You Need To Roast Coffee Beans At Home
You’ll need the following to roast your own coffee at home…
- Green coffee beans – If you live near a larger city, you will probably be able to get these somewhere near you! Check with a few local coffee shop owners to see if they’d allow you to buy a small quantity from them. If not, you can always pick some up online!
- Roaster – The type of roaster that you get depends on how often you’re planning on roasting! It’s even possible to roast coffee beans at home with a popcorn maker.
- Airtight storage container – After you’ve gone through all the work of roasting your own coffee, the last this you want is for your beans to go stale! We’ve written an article about keeping your coffee fresh for longer, we suggest you check that out before deciding on a storage container!
How To Roast Coffee At Home With A Roasting Machine
Once you’ve purchased your beans, you’ll need to buy a coffee roaster. We tried out a few, but narrowed it down to one great product.
With precise temperature control and a 750 gram capacity, this roaster gives the amateur coffee connoisseur the most bang for their buck! Unlike other, cheaper alternatives, this machine has a nonstick pan and automatic stirrers to make sure that your beans get an even roast every time.
Once you have your machine, follow the below steps for freshly-roasted beans:
- Gather, rinse, and dry your green coffee beans of choice.
- Decide what roast you’re targeting for your beans. If you splurge on a more expensive single origin bean, aim for a lighter roast! If you’re buying in bulk, you can err on the side of french roast.
- Put beans into roaster and select the respective temperature. Refer to our guide above on what range you should be looking for!
- Allow the beans to cool for 1-6 hours. The darker the roast, the longer you need to let the beans cool! Dump the beans out on a non-stick baking tray to speed up the process.
- Remove the chaff by sifting the beans back and forth between two colanders. Remember, you only need to remove most, not all, of the chaff.
- Enjoy! Congratulations, you just roasted your first batch of beans!
Before You Go!
Hopefully you found this article helpful. Whether you did or you didn’t, we appreciate you supporting our site! Our efforts here are fueled by you and a healthy dose of coffee. Feel free to check out our other articles, guides, lists, and more!
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