Hey Coffee connoisseur: Learn How to Roast Coffee at Home

When you play around with GGET’s Flavor Field online tool for comparing coffee, do you find yourself drawn toward light roast or dark roast, earthy flavors or citric? 

Do you wonder why you have those preferences and how you can make sure you always get the cup of coffee you’re craving? Learning how to roast coffee at home is one of the best ways to understand coffee at its core, and why you like what you like.   

It’s really not hard to make your own coffee. The basic process is like roasting any type of nut: you use heat to roast the raw beans. All you need is some type of home coffee roaster, a few pounds of green coffee beans, and directions. 

Your Home Roasting Coffee Machine

There are so many ways to roast coffee at home that we won’t go into all of them here. The important thing to know is that you do not have to buy an expensive roaster  in order to get started. Many professional roasters started with roasting beans in their oven or on a stove top.

How much coffee you want to roast at one time is important: it would take all day to roast five pounds in a hot air popcorn popper. 

Q: What are the types of home coffee roasters? 

The hot air popcorn popper is the easiest thing to use to start home roasting. You can also use the stovetop or roast the beans in your oven. If you’re really ambitious, you can make a stir-crazy, turbo home coffee roaster (which work very well, but require welding tools).

You can also use a skillet, a stovetop popper, or a cookie sheet in the oven. However, it’s hard to get an even roast with these methods. 

Home Coffee Roasting Appliances

If you want to go to the next level (or you want to start at the next level), you can buy a home coffee roasting appliance. Typically, they’re similar in design to commercial roasters, but can roast much smaller batches. They give you a built-in timer, a way to collect chaff (and there is always a ton of chaff when you’re roasting–it can be as thick as snow), and often a way to control the temperature and air flow. Some models even have smoke suppression. 

The thing to think about is whether you want an air roaster or a drum roaster.

Air roasters take less than 10 minutes to roast a batch of coffee, roast evenly, don’t scorch, and you can roast a small amount (giving you more options for experimenting with different roasts).  Drum roasters let you roast larger batches and provide a nice, even roast. The downside is you really have to pay attention and they get pretty smoky, as in you’ll need a way to vent the smoke if you’re using it indoors.

Visit Dripped Coffee to check out different home roasting appliances. 

Find the perfect green coffee bean

Once you have a way to roast your beans, you need to find the beans. You can’t walk into a coffee shop and buy green beans; you’ll need to buy them online. Fortunately, there are dozens of sources for buying green coffee beans, many of which will let you buy one pound at a time.  We suggest buying at least three pounds of any bean and experimenting with the different roast profiles to find your favorite. 

Q: Where can you find green coffee beans for roasting? 

Green coffee beans are not something you can buy at your local coffee shop. Fortunately, there are several online retailers that sell green coffee beans. Here are six of our favorites:

Ready, set, make your own coffee

Roaster, check. Green beans, check. Now it’s time to roast. 

The coffee roasting process is the same regardless of the type of roaster you’re using. However, roasting times will vary depending on the method you use and batch size. How much attention you need to pay to the roaster also varies by method. In general, expect each small batch to take about 10 minutes.

Q: What are the coffee roasting techniques?

1. Setup and Pre-heat

Find a place where the smoke can vent and the chaff won’t cause too much mess. Outdoors or in a garage is best, unless you really enjoy sweeping your kitchen–or unless you’re roasting in your oven or on your stovetop.

Find a space, such as a patio table and set up everything you’ll need: roaster, time, oven mitts, colander and wooden spoon (for cooling), glass jars for storing the roasted beans.

Preheat your roaster for about five minutes, which should get it to around 400 degrees. 

2. Prepare the Beans

Measure out the batch of beans so you can add them to the roaster once it’s heated. If you need to stir by hand, be ready to start once you add the beans; you don’t want them sitting still on the heat surface (that’s why an air popper is a good choice for the beginner–no stirring). 

3. Roast the Beans

The beans will pass through several stages as they’re roasting (which we describe in the next section). When you’re first starting, pay attention because this is where you control the roast profile of your coffee. You’ll learn how long it takes to get to each stage for your roaster. Also, you don’t want to burn your beans!

4. Remove and Cool

Once the beans are the roast profile you want, get them off the heat and cooling as quickly as possible. Dump them into a colander and stir with a wooden spoon. You can use a bowl, but the slats in the colander help cool the beans faster.

5. Store Your Coffee 

Once your beans have cooled, store them in an airtight, glass container. Mason jars work really well for this. Wait for at least six hours, preferably 12,  before sealing the jar to allow the gasses to dissipate.

The home coffee roasting process

Understanding the different stages of the roasting process helps you get the flavor you want from your coffee. It’s fun to experiment with different roast profiles to see how they mingle with the origin profile of your coffee. 

Q: How do you know when your coffee beans are done roasting?

Your beans will go through several phases while roasting. Practice using your five senses in each phase to determine when your coffee is done roasting. 

  1. Yellowing: For a few minutes, you’ll thinking nothing is happening as the beans remain green. The you’ll smell grass and the beans will turn a light yellow. 
  2. Steam: As their water content dissipates, your beans will start to steam. This is normal. 
  3. First Crack: Around the five to six minute market, the steam will become fragrant (and your mouth will start to water). The first crack is coming and the real roasting begins. You will hear the cracking sound. At this point, the sugars begin to caramelize and more water escapes as the bean’s structure breaks down and oils migrate outward.
  4. First Roasted Stage: Once you have achieved first crack, the beans are officially roasted. Now it’s a matter of your taste and the roast you’re going for. This first stage is called a City roast, which is a dry bean with a medium brown color. The City roast will be where  you be most able to taste the origin flavors over the roast.
  5. Caramelization: As the beans continue roasting, they caramelize more, the oils migrate, the roast gets darker and the beans get bigger. This is a Full City roast — where the beans are a deep brown color and the oil on the bean’s surface is heavy, intensifying the unique character of the bean — the trick is to pull the beans off the heat source when they’re on the verge of the second crack. Knowing how to anticipate this simply takes practice.
  6. Second Crack: The second crack is usually much louder and volatile than the first. This is where the roast character begins to overpower the origin character of the beans. This stage is called a Vienna roast. Caution: at this point, small pieces of bean may start escaping the roaster. Beware–they can hurt when they hit you.
  7. Darkening Roast: As the roast becomes very dark and the sugars burn completely through the end of the second crack, the smoke become more pungent (i.e. not as delicious smelling as earlier). The end of the second crack produces the French roast, which has a sweet and smoky flavor and is generally less acidic than the lighter roasts.
  8. Start Over: Sorry. If you get past the second crack, the sugars burn out completely. That is not good because all you’ll get from the coffee is a thin charcoal flavored water. 

There is no way around it, no shortcut: home coffee roasting is something you learn by doing. Eventually, you will make it to step 8. However, if you engage all five senses and a little bit of intuition, you will quickly get a feel for your home roaster and how quickly it gets to the different stages. 

Which roast is the right roast?

It’s fun to play with the balance between the “roast character” and the “origin character” of your coffee. The lighter the roast, the more prominent the origin flavor. So if you want to taste the difference between Palmichael, Colombian and Qirtira Goya, Ethiopian, go for the City roast. If you want to experiment with the roast character, play with the French roast. 

Ultimately, the roast you choose depends on what you like. 

What is important is to take notes so you remember what roast levels you like with different origins. Nothing is more frustrating than roasting the perfect bean and then completely forgetting what you did. 

Log how much your roasted at a time (1 cup, 2 cups, 1 pound), the temperature, how long until first crack, second crack, etc. Write down your thoughts about how the roast tastes: is it sweet, bitter, fruity? This is the way you’ll learn what works and what doesn’t. Before long, roasting will be second nature to you.

Um, that’s a lot of work. Are there other options?Learning how to roast coffee at home is fun, but you know what else is fun? Letting us do it for you. Check out the GGET Coffee Club and experience the joy of brewing a great cup of coffee at home.