I started roasting coffee at home about 7 years ago when a friend acquired a small electric restaurant coffee roaster from a friend of his. It looked like a portable kitchen stainless steel dishwasher with no instructions and we had no idea how to roast, so we bought a bag (70 lb burlap bag!) of green beans and started experimenting. We soon realized we had to move this thing outside because of the smoke. We had a blast smoking out the neighborhood and listening to the cracks, and our results tasted ok. We finally did an internet search and visited some local coffee roasters to see if they could figure out how to use this thing. Needless to say, I caught the bug, and have been home-roasting since, albeit on a smaller machine.
After my buddy moved and took the roaster with him, I went the route of the thrift-store popcorn popper. I finally found an original Poppery for $3 and have used it for about 5 years to roast. My wife thinks I am crazy, but she likes her lattes so she puts up with my crazy coffee hobby.
WHY THE GENE?
The Poppery works great, but I wanted to move the roasting inside the house for the winter, so I needed something that catches the chaff instead of blowing it all over like the Poppery. I narrowed my search to a Hottop roaster or Gene Cafe, eventually choosing the Gene because it was available locally instead of over the internet, and the US distributor is only 20 minutes away from me. The Gene is also about half the price of the Hottop, so after paying $3 for the Poppery, the $450 for the Gene was easier to swallow compared to the $850 for the Hottop.
The Behmor roaster is about $100 less than the Gene Cafe, and is good competition, but I do not believe in buying the first generation of any machine as no matter how well the machine is made/designed, there are always issues to be worked out. The controls of the Behmor seem overly complicated, and the visibility into the roast chamber of the Behmor, from what I have read, is not as good as that of the Gene.
Another positive of the Gene that I did not find until I brought it home is that it is made in South Korea, not China. Hopefully that means that there is less lead and other negative political baggage with the Gene.
USING THE GENE
The Gene's manually operated controls are attractive, compared to the other "computer controlled" coffee roasters I have seen during my buying research. I still go by the roasting philosophy that you have to smell, watch, and listen to every roast. I don't believe in setting a "profile" and expecting the same results. Every roast is different, even on the same machine with the same beans in the same ambient conditions.
The Gene has two knobs to control temp and time, and two digital displays. One display alternately shows the temp setting and current temp (of the air exiting the machine), and the other display shows the time remaining (counting down). Both the temp and time can be changed on the fly, allowing you to make the roast do whatever you want. The exit air temp doesn't really help determine the temp of the beans, but it is nice to know how hot the machine is getting. Hardcore techy coffeegeeks will not like knowing what temp the beans are, but again, I believe in watching the roast develop and using my senses to determine the bean temp and level of "doneness".
The all glass roast chamber is extraordinary in allowing you to watch the roast develop. There is nothing that I have seen that compares to the visibility that the Gene Cafe allows. The "off-axis" rotation keeps the beans moving and prevents hot-spots, giving you very even results. The airflow through the drum keeps the view relatively smoke-free and does a great job of blowing the chaff into the collector, after being scraped off by the metal flapper.
The large capacity makes this machine a superstar compared to using my old Poppery. I roast about 3 times the amount of coffee in the Gene compared to the Poppery. The Gene comes with a scoop the holds approximately 100 grams of green beans. The manual says that you can use up to three scoops per roast, or 300 grams total, but to use only 200-250 g. for heavily chaffed coffees. I do not use a scale, but instead use about 2.25 - 3 scoops. For me, 2.25 - 2.5 scoops seems to be optimum, but the full 3 scoops is just barely less even.
The roasting time is longer than the Poppery, but that is not necessarily a bad thing. The roasting "profile" I use is full heat (482º F) for 20 minutes. I just set the timer for 20 as a safety measure, in case I do get distracted and somehow forget that there is a coffee roaster in my house. As I said before, I sit and watch the roast develop, and add time or subtract temp as needed (not common). Just leaving the heat on full seems to approximate the large professional roasters (ie-Probat) that I have seen. The heat builds slowly and steadily through first and second crack. The 15-20 minute time for the roast is also what I have seen professionals do.
I mostly like a Viennese style roast for my espresso, so just when 2nd crack starts, I hit the cool button. The cooling cycle draws air through the heater coils to cool them at the same time, and the hot roasting chamber retains a lot of heat, so the beans "coast" into a Viennese roast by the time they are done. The Gene cools until the exit air reaches 140º F, which in my experience is about 8-12 minutes. I also turn my vent hood to high and open the Gene's plexiglass cover over the roast chamber during the cooling to help out as much as possible. Many reviews tell of stopping the roast and using alternate cooling methods, but I believe that the designers of the Gene knew what they were doing, so I would rather just leave the machine to do what it is made to do for the cooling. Trying to handle a 470º glass drum filled with smoking-hot coffee beans seems like asking for trouble.
I can finally roast coffee indoors with the Gene, as long as I use my range hood (vented to the outside!). I would not recommend this or any roaster indoors if you don't have a range hood or other ventilation. The large capacity of the Gene means there is a large amount of smoke. A recirculating vent-hood with just a filter will NOT do the job. Roast outside as long as the weather is warm (room temp or above) and dry. The chaff collector is large and well designed, but does not reduce smoke from what I have seen. In my opinion, smoke is just part of the roasting experience.
Well, not many that I have found. I defend using the Gene's cooling system above, but really, that is the only negative. The cooling could be faster/better. It takes a little bit of practice and experimentation to figure out when to hit the cooling button (push the temp control knob down) to get the results that you want, compared to being able to dump the beans and cool immediately. But the results are still top-notch. After you figure out how to work around the slow cooling, it stops being a negative.
The metal chaff scraper is in my "negative" section just because the loud thump on every rotation of the drum becomes annoying, but it does work just as it is supposed to. It scrapes the chaff off of the screen inside the drum, whereby it gets blown into the chaff collector.
As I mentioned above, the manual and warning stickers are an amusing translation from Korean(?) to English. Some of the gems are, "Gene Cafe produces optimal taste by separating coffee bean peels or harmful gas, reversely affecting the taste, in advance", and "In case the skin of the green beans inside the chaff collector catches fire - after the skins are burnt, it will be automatically distinguished. Do not panic and tend the place".
This is the only part that really matters. To start with, in my experience, any home roasted coffee tastes better than a coffee shop. Partly because it is FRESH, and partly because you did it! Really, if you research how to do it and know what to look/listen/smell for, you can roast coffee at home with any method and expect great results. The Gene just makes it easier to do all of that. The results I get using the Gene Cafe taste better than what I got from my popcorn popper because the roast is slower, more like a "professional" roaster, and the roast is easy to monitor. My first shot of espresso that I made with Gene Cafe roasted coffee was one of the best I have ever had. Not as "bright" as fluid bed/popper roasted coffee, but mellower, more "choclatey" (Sweet Maria's "Liquid Amber" blend).
I highly recommend the Gene Cafe to anyone that wants to improve or upgrade from a popcorn popper/roaster or other small roaster. Before buying the Gene, I would suggest that you have some roasting experience on a less expensive or home-made machine first, to learn how to roast and see if it is something that you want to stick with.
The coffee tastes better than most anything that you can buy and the large capacity allows you to prove it to your friends. It is easy to use, fairly quiet, and allows great visibility into the roasting chamber.
The build quality seems good (check back for 3 month & 1 year follow-ups) if you take care of it properly.