There was a time in America when if you wanted coffee, you had to roast it yourself.
The now-ubiquitous brown coffee bean used to ship to general stores green, with housewives usually roasting at home with a frying pan or — if she was lucky — a crank-turned home roasting system. With the advent of high-volume roasting companies in the mid-1800s and ever-improving freshness-sealed packaging, consumers no longer have to worry about roasting (or grinding for that matter) their coffee before brewing it.
Recently, the micro-roasting movement has brought roasting back into the home. For many coffee-lovers, home roasting is a way to ensure the freshest coffee in a rural areas, in the vast suburban Starbucks Sahara, or even just as a cheaper alternative to pricey high-end coffee mail-order services.
We tested six different home roasting methods. First, I tried four commercial options: the Nesco Professional, a Fresh Roast SR500, the Behmor 1600, and a Hottop. I also tried two DIY methods: a cast iron pan on a gas stovetop, and Whirley Pop popcorn maker I modified to work as a coffee roaster — a popular hack I found on the web. I did two or three test roasts on each machine with some green beans I grabbed from the show floor at this year’s Specialty Coffee Association of America (SCAA) expo. Then, for the final run, I roasted some high-quality beans given to us by the fine folks at Sweet Maria’s, a Bay-area coffee supplier.
Read the reviews of each individual roaster by clicking through the product photos at the top of this page. We also took a look at Bonaverde’s much-ballyhooed new machine that roasts, grinds and brews your coffee all at once. We didn’t get the chance to test it alongside these other home roasters — the 3-in-1 machine is still an early prototype — but you can read Mat Honan’s impressions of the Bonaverde on Gadget Lab.
The ratings of each tested roaster are based on four factors: ease of use, evenness of roast, cleanliness — roasting produces both smoke and chaff, and each roaster manages them differently — and the taste of the brewed coffee it produces. To keep things consistent, we roasted the same coffee (washed-processed Guatemala Huehuetenango Xinabajul, in case you were wondering) on each of the different machines to about a city roast level, or just after first crack. The next day, we cupped the coffees according to SCAA standards at the tasting lab of San Francisco roasting company Four Barrel Coffee. The resulting tasting notes were given by a round table of coffee professionals, home roasting enthusiasts, and one coffee-loving WIRED editor.
These reviews are written for those with some knowledge of home roasting. So if you’re interested in getting into home roasting but you aren’t familiar with the process, start by reading Sweet Maria’s guide to the basics. That link will also get you up to speed on all the lingo.
At first glance, the Behmor 1600 ($300) looks just like a toaster. Of course it’s not — inside the compact body is a perforated rotating drum and built-in chaff collector.
The Behmor has a programming system that will build a roast preset based on your bean quality and your desired roast level. Following the instructions, I was able to get a pretty good roast on my Guatemala beans despite not being able to watch the roast color very closely through the Behmor’s window and metal screen.
Loading the beans into the Behmor is tricky. Behmor recommends pre-heating the oven before starting the roast. But if you preheat for more than two minutes, a safety feature will prevent you from starting the roast. Even if you could load the beans in a hot roaster, it’s hard to place the drum in the hot oven because it is such a tight fit.
There’s no easy way to take the freshly roasted beans out of the Behmor right after they are roasted. Instead, Behmor wants you to let the beans cool inside the oven. Because of this, I had to make sure that I was pressing the “cool” button a little earlier than I wanted. Even though the Behmor’s cooling fan is strong, its stays hot inside the roaster for a while after you hit the button. To get a city roast level — the roast I was shooting for in all of these tests — I pressed the cool button as soon as I heard first crack happen. Even with the cooling fan turned on, I could hear the beans continue to crack as they cooled.
Coffee beans dispense their outer skin when roasting. It comes off in little flakes called chaff, and if your roaster doesn’t have a good chaff management system, the stuff ends up everywhere. Despite it’s chaff collector, the Behmor was not the cleanest roaster I tried. When you open the door, chaff flies out all over the floor. And don’t try to reach into the drum to brush away extra chaff. The directional fins cut my husband’s hand so badly, he was bleeding.
In our cupping test, the Behmor did not do so well. The coffee tasted oddly savory, like a beef stew or well-done steak. On top of the intense meat flavors, it also had a light lemony acidity. Some of the taste testers suspected that the simultaneous under and over-developed flavor notes might be because the coffee has to be loaded into a cold roaster and cools in a hot roaster, essentially robbing the beans of the flavor-packed oils that make them taste sweet or chocolatey. Similar notes were found in the Nesco Roaster, another machine that loads cold and cools hot.
Despite a few unpleasant tasting notes, the Behmor still emerged as a couple people’s favorite on the cupping table. Because the Behmor has so many different programming combinations and can handle up to one pound of beans at a time, I could imagine it being a good home roaster as you learn how to dial in and understand the machine’s settings.
WIRED Built-in chaff collector. Easy to use presets. Almost no smoke produced during the roast.
TIRED Hard to preheat and load. Awkward installation and removal of the drum. Difficult to monitor the color of your beans. Will draw blood.
Looking almost like an upside-down Kitchen Aid, the Nesco Professional ($220 MSRP, around $150 online) has a heating element in the bottom of the roasting chamber and a corkscrew that moves the beans around. The Nesco doesn’t let you play with all of the roasting variables. You can only control the amount of time of the roast, but you can add or subtract roasting time on the fly, which is a nice feature to have.
The Nesco’s vertical drum orientation and minimal chaff collection means that beans are completely immersed in their own chaff when roasting. The blind cupping revealed a chalky mouthfeel — a likely side effect of the Nesco’s rough roasting technique. It also had an overdone steak flavor going on and a lingering taste that one cupper described as “bluh.”
With a minimum allowed roasting time of 15 minutes, a pretty hot 5-minute cooling cycle, and few manual controls, the Nesco was the hardest roast method for me to get right. I played with pre-heating the roasting chamber and messed around with unplugging the machine and manually removing the hot beans to cool in a metal colander. But in the end, the most even roast came from just following Nesco’s instructions. Imagine that.
One of the nicest things about the Nesco is that you have a clear view of your beans during the roasting process. The Nesco also produced very little smoke, impressive considering that its small size doesn’t exactly allow for a big smoke-reducing afterburner. Also, its chaff screen was easy to clean, but probably because it didn’t collect all that much of the chaff.
Even though the Nesco looks like it could find a place on the kitchen counter, it’s not exactly a discreet device. It’s loud. Like really loud. So loud, I couldn’t even hear the first crack. And I wasn’t going to mention the Comic Sans font. But there, I just did.
WIRED Smaller than a Kitchen Aid. Not too smoky. You can watch the roast closely through glass.
TIRED Roasts with the chaff. Ridiculously loud. Made some really chalky-tasting coffee.
The smallest table-top roaster I reviewed, the Fresh Roast ($170) is a speedy little machine. About the size of a small blender, the Fresh Roast has a heating element in the bottom of the roasting chamber with a fan pushing the hot air up through the beans and out of the roaster’s lid/chaff collector.
As a user, you have three controls on the Fresh Roast: time, temperature, and fan speed — the roaster’s method for both agitation and heat delivery. The faster the fan speed, the more the beans move around, and (usually) the more even the roast. There are endless forum discussions dedicated to hacking the Fresh Roast to improve it, but I decided to work with what the manufacturer provided for the sake of this review.
Because of the Fresh Roast’s bottom-up fan design, it had the most efficient chaff collector out of all of the machines I tested. While it did keep things clean, the fan design also had some unwanted effects. The beans were not agitated evenly, leaving some beans almost zebra-striped while others were evenly roasted.
The quickest out of all of the roasting methods I tried, the FreshRoast will get your beans to first crack in less than six minutes — incredibly fast by most roasting standards. All of my attempts to prolong the roast time by adjusting the heat or fan speed resulted in really uneven roasts. After quite a bit of trial and error, I found that slowly lowering the fan speed throughout the roast improved the evenness and made the roasting process last a little longer.
The FreshRoast turned out to have many positive attributes on the cupping table. It was creamy and sweet with a dark chocolate body — likely because the air roasting keeps the chaff from burning up around the beans and adding a smoky flavor. That said, it wasn’t perfect. A couple people thought it tasted kind of dirty, but its positive flavors far outnumbered the negative ones.
WIRED Small enough for any kitchen. Best chaff collection out of all the roasters and it is possible to get a decent roast. Good tasting notes.
TIRED Takes a while to dial in. Difficult to get an even roast because of the fan design. If you’re getting a Fresh Roast, make sure you have a couple pounds of coffee to burn while you go through the trial and error process.
Retailing for between $820 and $1,000, Hottop machines are not for those just messing around. I got the Hottop KN-8828P-2K for this review, the newer and more expensive programmable model.
Fashioned after the huge commercial roasters that you can find in at your favorite coffee roasting company, the Hottop features a rotating drum heated by electrical coils. A live temperature read projects the bean temperature and a glass window shows your beans as they change color. Once you are done with the roast, it will drop your beans out of the roaster into the cooling tray.
The Hottop features two roasting settings — auto, and programmable manual. With auto, you pick the roast time and the Hottop will control the heat levels and exhaust fan throughout the roast. The programmable setting lets you choose the amount of time that your coffee spends at each heat level, as well as the fan speed of the Hottop’s exhaust manager.
One of the downsides of the Hottop is that you cannot easily adjust the roast on the fly. I’ve been told that the less-expensive $820 Hottop model allows for adjustments mid-roast, but I couldn’t figure out how to effectively change the time or exhaust fan speed while the roast was happening in the programmable version. If you do end up buying a Hottop, I recommend getting a lot of one kind of bean instead of ordering sampler packs. You need to have a couple goes with the same bean before confidently programming the roast.
The Hottop produced an insane amount of smoke. Initially, I dismissed this as a side effect of roasting nearly double the beans of the other roast methods (225 grams instead of 115). But even accounting for the bigger batch, it was really smoky. Worried I was doing something wrong, I quickly searched Sweet Maria’s forums to find out if other people had similar smoke issues. Most of the solutions involved roasting in the garage or putting a large exhaust fan in a window. Living in a small apartment, neither of those options made sense, so I just opened my windows and hoped the fire alarm didn’t go off.
The excess smoke is likely because of the Hottop’s design. Instead of blowing the chaff away from the heating element like the Fresh Roast or Behmor, the Hottop keeps the chaff inside of the drum, where it gets scorched by the heating element and burns off.
On the cupping table, the smoke that filled my apartment the day before was hardly present in the flavors of the beans. In fact, the Hottop was a clear favorite. It gave us flavors of butterscotch, stewed plums, and port wine. The cups were dynamic and clean, and could have easily fit in on the quality control tables of any top roasting company.
WIRED Best tasting coffee on the cupping table. The automatic mode made some great coffee. The programmable mode is easy to figure out.
TIRED Cannot adjust temperature, time, or fan speed on the fly. Hella smoky!
CAST IRON PAN
Comparing the modest cast iron pan to a roaster like the Hottop is a lot like comparing a bicycle with a Lamborghini. Yeah, both get you from point A to point B, but it’s not exactly a fair comparison.
I used a shallow 6-inch cast iron pan that we primarily use for making Irish soda farlsat home. We oiled it once when we first got it, but have since only used it for flour and dough. Before roasting the coffee for the cupping, I gave it a proper cleaning and used the cast iron for five coffee roasts, hoping to season it and remove any residual flour tastes. I roasted 100 grams of coffee at a time, constantly stirring with a brand new bamboo paddle.
I have never felt more connected to coffee than when I was stirring the green coffee in that cast iron pan. I kept the heat relatively high, watching the beans change color as I diligently stirred. There’s nothing between you an your roast. It’s mesmerizing, and very educational. You can really see how heat and agitation affect the coffee’s color and aroma. I recommend that anyone who is new to roasting try the cast-iron method at least once, if only to appreciate the ease and consistency of newfangled roasting methods.
The pan is definitely the quietest roasting method I tried. When the coffee started first crack, the noise was so loud it startled me. It sounded like popcorn, but the beans did not jump out of the pan. Instead, the chaff started to float. When the crack was almost finished, I took the pan off of the heat and tossed the coffee into the air a couple times, cooling it slightly while hearing the last few pops. Because the cast iron doesn’t have a chaff collecting system, I used two metal colanders to handle the beans, hanging out of my apartment window and letting the wind carry the chaff down the streets of San Francisco. (Sorry, neighbors.)
For being a thick metal pan, the cast iron performed pretty well next to its high tech competition. However, it was the definitely the worst tasting coffee on the cupping table. The dry smell of the ground coffee gave hints of cocoa and powdered sugar, but the tasting fell flat.
The cups auto-broke, meaning that all the grounds fell to the bottom of the cup before we had a chance to skim them. Without knowing what roast method was used for those cups, Four Barrel’s quality control director noted that the grounds probably sank because the roast method did not have enough airflow, and suspected that beans would show less caramel taste. And boy was he right. The cast iron pan’s coffee tasted like lemongrass, under-extracted jasmine tea, and lima beans — not exactly flavors you want from a typical washed-processed Guatemalan coffee.
That said, I felt like the flavor fail of the cast iron pan was more user error than anything else. I’m sure if I had more time to perfect it, I could have definitely improved the roast quality. There is plenty of historical evidence that cast-iron is an excellent roasting method, so I wouldn’t disregard it just because one tech writer couldn’t get it right after a few tries.
WIRED Quiet. Cheap. The most intimate roasting process.
TIRED Messy and labor intensive. The coffee’s smell wrote a check that the flavor could not cash.
HACKED WHIRLEY POP
One of the most common home roasting methods, the Whirley Pop popcorn maker can be used to roast coffee on the stove top. It’s the gateway drug that often leads to a full-on home roasting addiction. You can try to keep things simple by just measuring out some beans and cranking it on your range ’til they’re brown. But you will slowly start spiraling out of control, adding advanced measuring tools and eventually upgrading to some of the other machines on this list.
I did the basic Whirley Pop hack, inserting a thermocouple to the lid to watch the air temperature of the roasting chamber. I set my gas stove’s burner a little lower than what I used for the cast iron pan roast — the Whirley Pop’s aluminum bottom is much more sensitive to the heat.
Inside the Whirley Pop, a propeller turns and moves the beans around the bottom of the pan. It doesn’t fit flush to the bottom of the pan, so some smaller beans could get stuck under it and end up burning up.
My first roast on the Whirley Pop was completely ruined. The heat was way too high and I was not as diligent with my cranking as I should have been, so a good portion of my batch was burnt to a crisp while some was still green. But with practice, I was able to get a good pace and get a relatively even roast.
One downside to the Whirley Pop is you can’t keep a close eye on your beans. To keep the temperature inside the Whirley Pop consistent, you shouldn’t be opening the lid. But without peeking occasionally, you can’t see how your roast is doing. Various how-tos on the web say that a little lid flipping is OK, but to keep my variables consistent, I tried to roast without opening the lid at all. Instead, I listened to the beans and observed the aroma to decide when the coffee was done.
The Whirley Pop suffered from some of the same flavor issues of the Cast Iron pan. The cups both auto-broke, and the body was definitely lighter than the other offerings on the cupping table. Unlike the cast iron’s coffee, the Whirley Pop did have a few complex flavors. The coffee was very stonefruit-focused, with a little bit of brown sugar and citrus flavors going on.
Try this hack yourself — I posted instructions.
WIRED Good introduction to home roasting. Better results than the cast iron pan method for a similarly low price — around $20 on Amazon.
TIRED Needs a lot of attention. Very hands-on. Coffee won’t taste as good as a pro roaster unless you have a lot of practice.