Some of you, like me, may be more adventurous and hands-on when it comes to your hobbies. Coffee is one of those areas that you can enjoy while knowing next to nothing, or you can go into the darkest depths where you find yourself writing about roasting garbanzo beans in case you run out of the good stuff. 

Let’s suppose it hasn’t come to that.

Let’s pretend that supplies are plentiful, and you simply want to try your hand at going from start to finish. How can you go about roasting green coffee beans at home? Short answer:

The easiest method is to use an air roaster because it requires very little work and has a direct window to check the progress of the beans. After the “first crack,” they are ready for consumption.

However, with most things coffee, it’s more nuanced than that.

I’m going to start by explaining the basics of roasting, then going from the cheapest/hardest method and moving toward the more convenient/expensive methods – there isn’t much middle ground. Here we go!

Roasting Basics

• Smell: The beans will start with a grassier smell, especially as you start to roast them. This will give way to a bit of smoke that is closer to what we recognized coffee to smell like.
• Color: This is what they base the roast level on. The basic rule is that the darker the bean, the fuller the “body” of the brew. Here’s the way the colors seem to break down. I’m skipping “green” and “yellow”, and going straight for the meat:

• Cracking: depending on your roasting method, it takes somewhere after the 4-7-minute mark to hear the “first crack”. After you’ve heard this small crackle sound beginning, the beans are able to be used to make a brew. There is a second crack, which is important, but not as much as the first round. It still indicates that you’ve reached the midpoint between drinkable and burnt, as shown above.
• Aging: I’ve read some places that aging coffee is the best for flavor. The aroma will become weaker every day after roasting, but it appears that the optimal flavor is in the middle of the 2nd week (according to Boot Camp Coffee). Though the timing depends on the roast, bean density, bean size, and processing method, Greater Goods Coffee said they recommend it based on the method of brewing:
  1. Espresso: at least 5 days; best is 7-11 days of rest
  2. Drip/Pour-over: 4-7 days
  3. Cold Brew: 10-14 days

It’s interesting if you examine the progression; you may be as surprised as I was to see how the sweetness doesn’t peak in the lighter roasts. Instead, it appears to peak at the Dark brown (French / Espresso) roasts near the end. 

I will eventually write a more in-depth analysis of the processes behind roasting, especially since I was wrong in believing that light roasts were generally sweeter. Always room for growth!

There are four main approaches to roasting coffee at home, and each has its strengths and drawbacks.

Method 1: Frying Pan (Cheapest, Most Difficult)

For those on a budget and with limited supplies, this is for you. It requires more skill to get down well, and it will require more experimentation and finesse, but hey, it’s a challenge.

First off, you’ll need a frying pan that has: 

• Curved edges, like a wok
• No coating on it; stainless steel, carbon steel, or cast iron work best
• A thicker base

You’ll also need:

• Wooden spoon
• Metal colander
• Oven mitts (or equivalent, particularly if using cast iron)

Process:

1. Turn on your exhaust fan or open the windows. You want it well-ventilated because the beans will smoke.
2. With all your equipment and materials nearby, measure out ½ a cup of beans for your pan and see how much space you have left in your pan. You want it to be easy to stir without spilling them all over your counters.
3. Take the beans out and preheat the pan to medium heat. They recommend 450ºF/232ºC. The lack of control over the temp is where part of the finesse comes in. Some recommend a candy or deep-fryer thermometer, but that was for the popcorn popper.
4. Slowly stir the beans with the wooden spoon. After 5ish minutes you’ll start hearing the first crack, meaning they’re usable from that point on. Depending what roast you want, you’ll probably need 7-8 minutes before it becomes a nice light brown. Keep jostling them to make sure they don’t burn.
5. When you’re satisfied with the color, and it’s relatively uniform, dump the pan of beans into the colander and stir to help them cool faster. This will stop them from continuing to roast.
6. Once cool, they’ll still be emitting gas, so you’ll need to let them sit somewhere between 4 hours and overnight before putting them in an airtight container. If you put them in a container first, it might have pressure problems. Stored properly, they’ll be considered optimally fresh for 5-7 days. 

Method 2: Convection Oven

Since most people in North America have ovens, this is fairly easy to do, tools-wise.

However, it is a bit of a hassle. When I did it, we raised the temperature above the target because we kept having to stick our arms into the oven and shift the beans. Then we stopped it right after the first crack.

It didn’t turn out great, but it was a learning experience!

What you’ll need:

• A baking sheet with side holes or slot
• An oven
• A heat resistant spatula or wooden spoon. A long-handled one would be best.
• Metal colander

1. Preheat the oven to 450ºF/232ºC.
2. Lay the beans evenly on the pan, only one layer deep. They should be closely packed together, but not piling on top of each other.
3. Place the tray on the middle rack once the oven reaches temp.
4. Open the oven and stir them every few minutes to keep them even.
5. In total, it should take 15-20 minutes, depending on the roast level you want.
6. Remove from the oven, pour them into the metal colander, and stir to help them cool.

Method 3: Popcorn Popper

I’ll admit that I don’t know much about popcorn poppers. Some seem to be standalone machines with heating elements, and others require a stovetop. Some recommend the stovetop models that can be found at a second-hand store – optimally with a hand crank so you can control the speed.

You’ll need:

• Popcorn popper
• Metal colander
• Wooden spoon

If on a stovetop, the temperature should be around 450ºF/232ºC – a deep fryer or candy thermometers are recommended. Start in a well-ventilated area.

The beans should constantly move so that they cook evenly and don’t burn. 

About 4-7 minutes into the roasting, you’ll hear the first crack. Coffee-smelling smoke will start to appear, so you’ll be glad that you’re in a well-ventilated environment.

Continually check the color until it is where you want it.

Pour them to a metal colander and stir the beans with the wooden spoon to allow them to cool.

Method 4: Air Roaster (Most Expensive; Easiest)

These are relatively new, at least to me, and great for making wings. Also known as a “fluid bed roaster”, they’re a bit more expensive than the other options, but people say they’ll result in a fairly even roast without constant attention. 

They work by blowing hot heat over the contents, roasting them more directly and quickly than a convection oven.

Some models you can find are:

• VonShef Air Fryers (line of air fryers)
• Gourmina GTA2500 Air Fryer (specific air fryer)
• Hearthware I-Roast 2 (dedicated coffee roaster)
• Nesco Professional (dedicated coffee roaster)
• FreshRoast8 (dedicated coffee roaster)

Generally, you need a wire rack that will suspend the beans in the middle of the roasting chamber. Most have a clear section in the lid so that you can monitor their progress. It’s much less work because there’s no manual stirring involved, and it’s easy to see how far along they are. 

Listen for the cracks and keep an eye on the color, then turn it off and let it air out, stirring them in the wire rack to help them cool faster.

TL;DR

It’s really hard to do a “too long; didn’t read” summary for this one. Each section is as concise as I could make it, so I recommend perusing the bolded lines for the shortest experience.

If you have any further questions, please comment below, and thank you for your interest!