How to Roast Coffee Beans at Home

Roasting coffee adds another dimension to your understanding of and enjoyment of the beloved beverage. It’s easy to get started, and you don’t need to invest in a lot of expensive equipment. With some green coffee beans and a basic setup, you can begin roasting coffee at home.

As soon as you brew your first batch of roasted coffee, you’ll immediately notice the difference that fresh roasting makes. Beans that were roasted just a few days ago are much more aromatic, flavorful and lively than those that were roasted months or years ago (like those that you might buy at the store). Even if you don’t get the first batch absolutely perfect, you’ll pick up on finer notes that aren’t present in stale coffee and you won’t want to go back to the old stuff.

From sourcing green coffee beans and selecting a roaster to actually roasting that first batch, here’s how to roast coffee beans at home.

Sourcing Green Coffee Beans

The coffee beans that you brew coffee from are roasted beans, and these are what you purchase at stores, cafes and roasteries. To roast coffee, you need green coffee beans.

What Are Green Coffee Beans?

Green coffee beans are simply unroasted coffee beans. The beans are actually the pit of the coffee cherry fruit, and they have a greenish (sometimes yellowish or blueish) hue. Any unroasted beans are green beans, and all green beans must be roasted before brewing.

Where Can You Purchase Green Coffee Beans?

Aside from Kona coffee that’s grown in Hawaii, all other coffee is imported into the United States. Most is imported from Central America, South America, Africa and Southeast Asia, and importers usually work with distributors who ultimately sell coffee beans to roasters.

Most home roasters get their green coffee beans from two main sources, although there are some others. Most distributors who sell to commercial roasters aren’t set up to service home roasters, as they sell beans by the 60-kilogram (130-pound). The two main sources that many home roasters do rely on are local roasteries and Sweet Maria’s.

Most local coffee roasters will sell you some green coffee beans if you ask them. While a few may decline to, commercial roasters are usually more than willing to share green beans with someone who’s interested in roasting coffee themselves. Commercial roasters typically get into the business because they love coffee, and it’s always fun to connect with someone else who shares the passion.

At local roasters who regularly sell green beans to home roasters in the area, prices for green beans are normally a little less than roasted coffee bean prices. Discounts commonly range from $2 per pound to half-off the roasted coffee price.

Local roasters who don’t regularly sell green beans aren’t as uniform in their pricing for green beans, and some might charge the same as they do for roasted beans simply because their system isn’t set up to allow a green-bean discount. At these roasters, it can be helpful to have cash when inquiring about green beans.

Sweet Maria’s is an online retailer of green coffee beans that specifically serves home roasters, and they’re highly regarded by the home-roasting community. Sweet Maria’s offers an extensive selection of green coffee beans at reasonable prices, and they have excellent resources for the home roaster.

If you’re ordering from Sweet Maria’s and expect to continue roasting coffee, consider ordering a good amount of beans from them. Coffee is heavy, and shipping costs are significant. Sweet Maria’s base shipping fee covers up to 20 pounds of green beans, allowing you to spread the shipping over quite a lot of coffee and reduce the per-pound shipping cost as a result. Expect to pay around $6 per pound (not including shipping) although you can get a slight discount for bulk orders or may pay more for a specialty microlot.

Moreover, you can order a lot of green beans at once without worrying about them going bad. Green coffee beans last much longer than roasted coffee beans, and they’ll keep for months without issue as long as you have them in a cool, dry place. Many commercial roasters keep green coffee beans for close to a year so that they can continue roasting their blends even when the coffees in those blends aren’t being harvested by growers.

There are other online retailers that sell green coffee beans, but Sweet Maria’s has the best reputation.

What Kind of Green Coffee Beans Should You Buy?

When buying green coffee beans, purchase arabica beans and purchase what you like. The same general guidelines hold true when buying roasted coffee beans.

Coffea arabica is the main species of coffee that’s used for specialty coffee, and it tastes much better than coffea robusta. Robusta has more bitterness, which stems from the higher levels of caffeine in it (caffeine is a natural pesticide that’s bitter). There are a few other hybrids that contain a mixture of arabica and robusta, but arabica will give you the best flavor.

If you’re purchasing coffee from a local roster or well-respected online source, the coffee selection will likely be limited to coffea arabica.

Outside of getting arabica, there’s no hard-and-fast rule on what makes a good coffee. Select any region or flavor profile that you like, and you can use any roasted coffee that you’re familiar with if you don’t know where to get started. If you had an African coffee that was really fruity and enjoyed it, select a few pounds of green beans from Africa and see how they taste. If you prefer a nutty coffee, look for a Central American or South American lot that shows nuttiness in its flavor profile.

Roasters and suppliers that you consider purchasing from will be able to tell you what sort of profile a particular green coffee selection has. They all perform cuppings when selecting coffees.

While the guidelines to purchase coffea arabica and get what you like are all that you need to follow, there are a few tips that can help you find especially good selections. You’ll learn more about coffee lingo if you keep roasting, but the following are a few notes to get started with:

Cupping

A coffee cupping is a specific way of brewing and tasting coffee to rate it. Among other rankings, a coffee will have an overall cupping score. The score is out of 100, and anything that’s truly over 85 is very good — a coffee over 90 will be one of the best coffees you’ve ever had. (Many people in the industry inflate cupping scores slightly.)

Elevation

Coffees grown at high elevations mature more slowly and are denser as a result. While this can make roasting them slightly more challenging, it generally produces more nuanced flavors. The actual elevation of a lot is often noted, but there are other ways of demarking a coffee as grown at high elevation. “Strictly hard bean,” “SHB” and “altura” all refer to elevation.

Processing

All green coffee beans are processed, and the processing method affects the overall profile of the coffee. Expect “washed” coffees to have a clean and uniform profile, and “unwashed” or “natural processed” coffees to be more exotic. “Semi-washed” and “honey processed” fall in between.

Flavor

Regions have common flavors, but there are exceptions to these. The best way to assess a particular coffee’s flavor is to look at the roaster’s notes on what it tastes like.

There is a lot more to learn about the terroir of coffee, and even this much information might seem daunting. Don’t be intimidated, however. Simply select some green coffea arabica beans that sound tasty, and you won’t be disappointed.

Choosing a Coffee Roaster

You’re going to need a roasting device to roast coffee, and there are many apparatuses that can work when you’re starting out. As you consider the following options, there are a few items to keep in mind.

The main role of a roaster is to quickly and evenly heat your green coffee beans — and those three factors are primary ones to keep in mind:

  • Heat: Coffee must be roasted to at least ~385°F (~196°C), and darker roasts can reach 435°F (~224°C) or higher. Your roasting device must generate enough heat to get green coffee to this temperature range.
  • Speed: Coffee will take on a “baked” flavor and lose its finer flavor notes if roasting takes more than 15 to 20 minutes. Therefore, roasting a batch of coffee within 20 minutes (preferably 15) is necessary for maximum flavor.
  • Evenness: Coffee beans should be as evenly heated as possible for uniform flavor. Some roasting setups are better at this than others, but those that don’t evenly heat can still be used for your first few batches to see whether you like the hobby.

In addition to these primary criteria, there are a few secondary considerations to keep in mind as you sort through the different roasting setup options:

  • Smoke: Roasting coffee products a lot of smoke, because you’re essentially burning the beans. Some coffee roasters have built-in catalytic converters to mitigate some of the smoke, but not all do. Look for a well-ventilated area where you can roast if your roasting device doesn’t have this feature (and perhaps even if it does).
  • Location: The right location will balance your need for ventilation and a stable temperature. While the ideal spot would provide sufficient ventilation and a stable temperature, a perfect spot often isn’t available to the home roaster. A garage, carport or sheltered outdoor space might have to suffice when starting out. The variations in ambient temperature will make it difficult to replicate a precise roast, but you can still learn the basics and create good roasts in these settings.
  • Visibility: Green coffee beans produce several visual and auditory clues as they go through the stages of roasting. Especially as a novice roaster, you’ll have an easier time determining where in the stages a batch is if your device allows a good view of the beans as they’re roasting.
  • Yield: Most home coffee roasting setups roast a half-pound of beans or less. Yield may not be a major factor when starting out, but you might want to keep this in mind if you invest in a higher-end roasting device later on. Having a larger yield is especially nice if you regularly roast coffee for multiple people.
  • Price: There are coffee roasting devices for all budgets, and you can even get started with an old frying pan. Broadly speaking, the different price ranges for a home roasting device are under $50, $100 to $200, around $500 and around $1,000.
  • Features: Some roasting devices have additional features. These are peripheral things that can be nice, but they’re far from necessary.

Ad-Hoc Homemade Coffee Roasters

If you don’t want to invest in an actual coffee roaster, there are several ad-hoc setups that can be created for very little. These don’t always heat beans quickly or evenly, but they can be sufficient for the new roaster (and even some experienced ones still use them). The main advantage of these are that they cost very little.

Oven

You can theoretically roast coffee on a cookie sheet in your oven, perhaps stirring the beans half-way through to create a more even roast. An oven isn’t recommended, however, as you’ll likely be smoked out of the kitchen.

PROS

  • Price
  • Heat
  • Speed
  • Yield

CONS

  • Evenness
  • Smoke
  • Visibility

Heavy-Duty Frying Pan

An old heavy-duty frying pan will work if you have access to a hot outdoor fire. You won’t produce the best roast profile, but it’s fun to roast coffee directly on a charcoal grill or fire.

Make sure the frying pan is old, because it’ll likely be ruined for any other purpose. Also, make sure you’re outdoors. Doing this on the stove isn’t recommended because of the smoke produced.

To roast coffee in a frying pan, put coffee beans in the frying pan and put the pan directly on your heat source. Stir the beans continually as they go through the roast stages.

PROS

  • Price
  • Heat
  • Yield
  • Speed
  • Visibility

CONS

  • Smoke
  • Evenness

Whirly Pop

A Whirly Pop can be used on an outdoor fire much like a frying pan. The lid on these reduces visibility, but it makes for more even heating than a frying pan. There’s also a built-in handle that you can still stir with. You can find new Whirly Pops for around $25. Akin to a frying pan, don’t expect to use a Whirly Pop for popcorn after roasting coffee in it (unless you want coffee-flavored popcorn).

PROS

  • Price
  • Heat
  • Speed
  • Yield

CONS

  • Visibility
  • Smoke

Grill Roasting Kit

A few specialty companies make drum kits that are specifically designed to fit on a grill. These take advantage of an outdoor heat source that many people have, and the drum rotates the beans as they roast. These kits vary widely in both size and price. You can find smaller ones for just a few dollars, and much larger ones can run as high as $1,000 or more.

PROS

  • Price range
  • Heat
  • Yield
  • Location

CONS

  • Visibility
  • Evenness
  • Speed

High-Temperature Toaster Oven

A toaster oven can be used for smaller batches much like you’d use a normal oven for larger batches. Simply spread a single layer of green coffee beans out on a tray, and roast them in the toaster oven. The advantage of a toaster oven is that you can take it outside of your kitchen.

A toaster oven won’t produce an even batch, for the center of the oven is much hotter than the edges. Additionally, you can’t open the door to stir beans because the oven isn’t strong enough to maintain its temperature when you do. Opening the oven door mid-roast will result in a baked roast, if the beans roast at all.

Should you decide to use a toaster oven, look for a model that heats to at least 450°F (232°C). Those that only go to 400°F (204°C) won’t be able to get all of the beans hot enough. Since you’ll ruin the toaster oven, you probably want to look for a used one online or at a thrift store.

PROS

  • Price
  • Visibility

CONS

  • Heat
  • Yield
  • Evenness
  • Speed

Old Air Popper

Old air poppers are a common favorite among beginning home roasters, for roasting coffee is a lot like popping popcorn — coffee beans even “crack” (or pop).

Coffee must be roasted to a higher temperature than popcorn gets to, though, so you need an older model air popper. Newer models have safety shut-offs that keep then from getting hot enough to roast coffee. Older air poppers are readily available on Ebay for anywhere from $15 to $50.

PROS

  • Price
  • Heat
  • Evenness
  • Speed

CONS

  • Visibility
  • Yield

Ad-Hoc Recommendation: Of these ad-hoc setups, the air popper is probably the best and most popular choice.

Entry-Level Coffee Roasters

If you want an actual coffee roaster, the entry-level models are usually priced between $100 and $200. There are many to choose from, but the following are three well-known ones (although not always liked).

One of the biggest advantages of these roasters is that you can control the temperature much more accurately than you’re able to on any ad-hoc setup.

Nesco Coffee Bean Roaster

The Nesco Coffee Bean Roaster is perhaps the most affordable coffee-specific roaster. The roaster is limited in features, offering only a medium roast, dark roast and temperature control — but it can be found at many retailers for less than $100. The roaster also helps mitigate some of the smoke, which is helpful if you’re roasting indoors.

The Nesco’s batch size is limited because it has such a small profile. If you’re in a small apartment, though, the smaller profile might be an advantage.

Nesco previously made a roaster that’s known as the Nesco 1010. Should you find a used Nesco 1010 for sale in good condition, this was a much more capable roaster and worth considering.

PROS

  • Price
  • Heat
  • Evenness
  • some smoke control
  • Speed

CONS

  • Visibility
  • Yield

Fresh Roast SR540

Fresh Roast is one of the most ubiquitous coffee roaster manufacturers, and the SR540 is their budget model. The roaster allows for easy adjustments and is able to roast about 4 ounces of coffee at a time (the official limit is 5 ounces). With intuitive controls and the ability to change time, temperature, fan speed and desired roast level, this is a great model to learn on. The Fresh Roast SR450 is usually a little below $200.

Jiawanshun JW-468LY

The Jiawanshun JW-468LY isn’t the easiest roaster to find, and it’s pretty limited in capabilities. It’s one of the few roasters around the $150 price point that can handle over a pound of beans at a time, however. For that specific reason, it may be worth considering if you’re roasting a lot of coffee and on a tight budget. If you don’t need that batch size or have a larger budget, there are better options.

(Jiawanshun’s multi-purpose appliances that the company suggests both cooking food with and roasting coffee with aren’t recommended.)

PROS

  • Price
  • Heat
  • Evenness
  • Yield
  • Speed

CONS

  • Visibility
  • Smoke
  • Lack of controls

Entry-Level Recommendation: Of these entry-level machines, the Fresh Roast SR540 offers the most capabilities and still has a reasonable price.

Mid-Tier Coffee Roasters

Stepping up to mid-tier coffee roasters brings a lot more capabilities, and most people who continue roasting coffee at home eventually purchase one of these. Prices for these roasters hover around $500.

Kaldi Home Coffee Roaster

The Kaldi Home Coffee Roaster automates nothing, which means you’re in control of everything from the time and temperature to the rotation of the drum. This can be intimidating if you’re brand-new to home roasting, but it’s lots of fun to experiment with once you know the basics already. A major drawback of the Kaldi is that it requires gas rather than electricity to run. This roaster is usually a little under $500.

PROS

  • Heat
  • Evenness
  • Many controls
  • Speed
  • Visibility

CONS

  • Location (requires gas connection)

Behmor 2000 AB-Plus

The Behmor 1600 has been a mainstay among home coffee roasters for years, and the Behmor 2000 AB-Plus was recently released in June 2020. The roaster features lots of profile options and is an all-around well made roaster. The newest version has some internal upgrades that afford better control, and Behmor can deliver firmware upgrades remotely.

Compared to the others at this level, the Behmor is known for having reduced visibility and needing to “coast” at the end of roasts (see roasting steps). The roaster offers more information and controls, however, and it’s widely used. Expect to pay a little under $500 for a Behmor 2000 AB-Plus.

PROS

  • Heat
  • Evenness
  • Speed

CONS

  • Visibility

Gene Cafe CBR-101

The Gene Cafe CBR-101 is another mainstay among home roasters. This roaster allows for full time and temperature control, which makes it easy to operate if you’re a beginner yet allows you to fully customize roast profiles if you’re an expert.

The Gene Cafe CBR-101 is known for being louder, and sometimes it’s hard to hear the “cracks.” Most roasters who use this frequently learn to pick out the first and second crack from the other noises, however. Also, the roaster’s glass chamber affords excellent visibility. Expect to pay a little less than $600 for the Gene Cafe.

PROS

  • Heat
  • Evenness
  • Visibility
  • Speed
  • Control

CONS

  • Sound

Recommendation: The Behmor and Gene Cafe roasters are in direct competition with each other, and both are great choices. Many home roasters love each one.

High-End Coffee Roasters

The next major step up in roasting equipment comes around the $1,000, but this is probably more than what you need as a novice home roaster. Many home roasters are perfectly content to use their Behmor or Gene Cafe, never investing in anything higher.

Also, most of the roasters at the $1,000 price point switch to gas rather than electric. This consideration alone makes them impractical for most home roasters.

Choose Your Roasting Device

As you consider the many different roasting device setups that are available, remember that you don’t need the best coffee roaster to produce a flavorful batch of coffee. When you’re starting out, even a simple setup that makes a less-than-perfect roast will taste great. The biggest factor is how recently your coffee was roasted, and that alone will make anything you roast stand out from commercial coffee that’s older.

Roasting Coffee Beans

With green coffee beans and a roasting device, you’re nearly ready to roast your first batch of coffee. The only other thing that’s helpful is some basic knowledge of the roasting process.

The Roasting Process

Like any other form of cooking, roasting green coffee beans is a process that involves temperature and time. You can experiment with these two variables as you become more familiar with the process, but even complex roasting profiles ultimately come down to time and temperature. What temperatures are applied and what is the timing of those temperatures?

(This is why a coffee roaster like the Gene Cafe affords great control and variability even though it doesn’t have any roast profile settings. It allows you to direct control of time and temperature for a profile that you personally set.)

The Stages of Roasting Coffee

As temperature is applied over time, the green coffee beans will go through several stages as they become roasted coffee beans. The reactions of the sugars, oils and gases in the beans create each of these stages.

  1. Yellowing: Yellowing is when the green coffee beans transform from green to yellow. This is the beginning of the Maillard reaction, which is the same enzymatic reaction of sugars that turns an apple brown. The sugars in the coffee beans are beginning to become brown. You’ll notice a grassy smell in addition to the yellowing.
  2. First Crack: The first crack is defined by a faint cracking sound that’s the result of gases escaping from the beans. The beans are forced to expand as the gases escape, and the expansion creates the sound. The beans will also begin to turn brown as sugars caramelize, and the oils on the beans will start to come to the surface. The chaff on the beans will fly off as the beans expand. First crack occurs when the beans reach an approximate temperature of 385°F (196°C).
  3. Second Crack: The second crack is defined by a more pronounced cracking sound that’s the result of more gases escaping from the beans. The beans continue to expand, and the continued expansion creates noticeable larger beans. The beans are shiny by this point because the oils have come to the surface. The smoke also will become more pronounced, and it often takes on a blue hue.
  4. Mythical Third Crack: The third crack is a mythical stage that features both a pronounced cracking sound and the sound of sirens shortly thereafter. You’ll be phoning the fire department if you go beyond the second crack to this stage.

The first crack and second crack are two reliable stages that every roaster should be familiar with. The completion of first crack is the initial point at which coffee beans are drinkable, and second crack is when the beans are entering a truly dark stage. The cracks also always occur around the same internal bean temperature, so they’re helpful in gauging roast level.

For reference, City Roasts are about 0:30 to 1:30 after first crack is finished. Second crack marks the transition from Full City+ to darker roasts, such as Vienna, French and Italian.

How to Roast Coffee at Home

With the background knowledge of the roast stages and some basic understanding of roast levels, here’s a practical guide on how to roast coffee at home.

Choose a well-ventilated area where the smoke will dissipate, and set up your roaster to get started. As you fill the roasting chamber, fill the roaster to just below maximum capacity. The extra space will allow for better air circulation, which will improve evenness and help ensure the roast is completed quickly enough to avoid a baked flavor. This is especially important if roasting dense beans, such as natural-processed or high-grown coffee beans, because they require more heat to reach a suitable internal temperature.

To get you started, follow these general steps as you roast:

  1. If your roaster has temperature adjustments, bring the beans up to about 365°F (185°C) for 1 to 3 minutes. Although this prolongs the roast time, it will help the beans reach the first crack closer to one another and result in a more even roast. 1 to 3 minutes shouldn’t produce a baked taste, and home roasters often heat unevenly if you don’t do this.
  2. Turn the heat all the way up and watch for the roasting stages. You should notice yellowing, the first crack and the second crack if you roast that far. Use sight, sound, smell and roaster-provided data to monitor the roast level.
  3. Stop the roaster one stage before your desired roast level (e.g. at Full City if you want a Full City+ roast). Home roasters take a few minutes to cool down, and the roast will “coast” to a slightly darker roast level.
  4. If your roaster doesn’t have a built-in cooling function (e.g. if you’re using an air popper), dump the beans out of the roasting device and into a metal sieve. Gently toss the beans back and forth between this sieve and another to cool the beans and allow the chaff to blow away. Metal or porcelain bowls can work too.
  5. Let your roast degas for about 2 days before brewing it. There is carbon dioxide in the beans that remains after roasting, and the beans should sit for about 48 hours to allow a good amount fo the carbon dioxide to escape. You can store them in an old coffee bag or a paper bag. Air should be able to escape from the container.
  6. After a couple of days, the beans are ready for brewing.

If you haven’t brewed freshly roasted coffee before, you’ll notice that the grounds bubble up during brewing. This is more carbon dioxide escaping from the beans after they’re ground, and the brewed coffee will taste sour if the gas isn’t allowed to escape. The carbon dioxide forms bubbles around the ground that interfere with extraction, and the gas itself doesn’t taste great.

To let the carbon dioxide escape from the grounds, you should allow the grounds to “bloom.” Dampen the grounds with hot water, and give them 40 seconds to bubble. After 40 seconds, brew your freshly roasted coffee like normal — you’ll love how the cup tastes.

Enjoy Roasting Coffee at Home

Roasting coffee opens up a whole new realm to you, and it’s a great hobby to get into. Enjoy savoring your first batch of home-roasted coffee, and then experiment with future ones. Between bean selection, roast profile and brew method, the possibilities are virtually endless, and they’re certainly a lot of fun to explore.