Okay, I'm a newbie on roasting. I searched this forum, but couldn't find my answers. So here are my questions:

- Does anybody have some nice basic roast profiles for the Gene Cafe roaster?

- Is there some sort of temperature off set for the Gene?

I tried some of the profiles I found on HB, but it seemed that the temperatures mentioned, did not match what I found on my Gene. For example when someone said first crack should be found at 215C after 10 minutes (or so), on my machine it would only occur at 230C (and thus after 12 minutes). You can imagine that my first attempt was a 18 minutes roast, with a slow ramp (coffee tastes good, though).

So to me, it seemes that the readout shows like 15-20 degrees Celsius higher on the Gene, than it is actually in the coffee itself (something to do with airflow temp. whatever??). Is this true? Or should I read the profiles found here exactely, and copy them to my Gene?

Hope you can help me with this,

Thanks in advance.

The only "profile" that I use is full heat.... the whole time.

I get the best results when I pre-heat the drum all the way to 482F (250C, the maximum), unplug it, pull out the drum, fill with pre-measured green coffee, put back in the machine, plug back in, turn on and roast at 482F/250C until the first few snaps of second crack. I have gotten my pre-heat and roasting re-start routine down to about 10 seconds, but be careful while doing this.

With this method, 1st crack is approximately at 8 minutes, 2nd starts around 12-15, depending on the beans. When I first re-start the Gene after adding the beans, the temp goes down to 400F/200C, then slowly comes back to about 455-470F/235-243C where second crack starts and I begin the cool cycle.

I have a rear down-draft type stove vent, so I push my Gene against the vent and run the cool cycle with the vent pulling air over the drum, this shortens the cooling from 10 minutes to 8 minutes. Still a long time, but my coffee results are tasty. I keep the Gene away from the vent while roasting so that just the smoke gets pulled into the vent, keeping the Gene as warm as possible.

I have never tried to follow any other profile, and this is the method I have seen recommended by other Gene owners. This also roughly approximates the method that a friend uses for her commercial coffee roasting on a Probat, albeit she uses more finesse and some "secrets". When she saw my Gene in operation, she recommended this method. Sweet Maria's also recommends full heat, but they do not do the pre-warm.

Hope this helps-

I have roasted on the Gene, going on 3 years.

^ Preheat unit with hopper in to 175C.
^ Premeasure 230grams
^ Hit E stop and move like the wind
^ Use dual settings.
a. High grown or dense beans: 248C into the first crack plus 45 seconds. Then turn down
to 243C until 2:30 minutes past initial crack of first crack (try to stay out of 2nd crack). I call this a full city roast and is my starting point for working on a new bean. I can shorten/lengthen based on cupping results. Most beans finish between 12:45 and 14:00 minutes.
b. Brazilians, some Indonesians, intermediate elevation beans: 243C/237C, profiled
above
c. Konas and Caribbean beans: 237C/232C , profiled above

I end the roasts with an E stop and cool my beans externally. My current is a steady 120 (variac controlled). My assumption is that you have 220V so trust
that the profiles can be superimposed onto your unit.

These have become my tried and true profiles after tinkering around, trying others' posted
profiles, and settling on a profile that seems to caramelize the sugars and give me the fullest
measure of what is in the bean.

Good luck, B|Java

Greetings,

I run the Gene with beans in the chamber for 3 minutes with the temperature set at 310 F. I then use the simple profile from Tom at SweetMarias.com which is set the temperature to 482 F. and when first crack is heard drop down to 460 F. and run until you get the degree of roast you want. I then hit the button that starts the cool down cycle but I only let it run for a minute then hit the button again to put the Gene in emergency stop, remove the chamber and empty the beans into a strainer and place the strainer over a blowing fan. The beans cool faster using this method.

Cliff Isackson

Thanks for the replies so far, guys!

What I understand is:
-That it might be a good idea to preheat.
-That I should use like 240 grams of coffee.
-That the drying fase will go by itself, by setting the Gene to full (it takes that long).
-That I don't need to bother too much for the numbers. Just go ( after drying) as quickly as the Gene permits, to the max temp.
-When 1-st crack: turn the temp a little down. Then take it as far as I want to.
-Cooling preferrably outside the Gene.

Something like this? Am I right? So no fiddeling with the temp, like after 4 minutes: a 10 C ramp up per minute until 10 min., after that a gentle ramp up of 5 C p/m... or something like that?

And what about the temperature read out on the Gene, is it correct or is there some sort of offset?

Thanks again!

Greetings,

The temperature reading you see is the exit temperature from the roasting chamber. You really can't tell what the temperature of the beans are. I wouldn't waste time with 3 minutes at this temp and 2 minutes at another. Keep it simple. If the beans produce alot of chaff you might want to lower the grams to around 210, keeps the chaff from starting on fire.

Cliff

You have been given 3 different set of instructions that each poster finds best with their machine. I might suggest that you take a nice high grown and try each of these 3 approaches. They are different; they are not the same.

Cup the beans after 3-4 days rest and find out which profile works best on your system. Then you will have the best instructions for your system and you can tweak from there.

B|Java

The instructions didn't seem too different to me, so I tried to make some sort of a resumé. I can see there are "little" deviations from what I thought all combined (and of course these deviations can make big differences).

My intention was to start from what I wrote, and then try everyone's personal touch. Is that a good idea? It is a starting point. For instance, I know now that I don't need to bother changing the temp every minute (some profiles I read do that), and that cooling outside the Gene is better.

Thanks for your input.

I forgot to add that my "profile" (high heat the whole time) is for espresso. I use SM espresso blends and only roast for espresso preparation. I try to follow Tom's advice and keep my espresso at Vienna roast or less, but sometimes I just can't resist a darker French.

If you are roasting for a more delicate or subtile bean or blend, or if you drink regular coffee (press, pour-over, etc) then you may want to try some of the other profiles with the lower heat settings.

The advice from my commercial-roasting friend is that she thought that the Gene didn't have the power to adjust temp fast enough to make a large difference, that is why she recommended full high heat and judge your roasting by sight and smell. Also, once the green beans are added, the slow increase of temperature seemed to approximate the time profile of her Probat roaster.

As for cooling, outside of the Gene is obviously the best, but if you compensate and start your cooling cycle a little early, it is not too difficult to let the beans "coast" into the desired roast. That is how I get a Vienna by starting the cool cycle at the first snaps of 2nd crack. By the time the beans have cooled enough to stop snapping, about 5-10 seconds, they are at a nice Viennese roast.

I also think that from everything I have read about different people and their Gene's, that each unit is slightly different and has a slightly different personality. I have checked mine with a Kill-a-watt and my voltage stays a constant 117 during the roast, +/- 1 volt.

Post your results when you get a chance to roast again. I am curious about what method you will use and the results.

Bill

The advice from my commercial-roasting friend is that she thought that the Gene didn't have the power to adjust temp fast enough to make a large difference...

It seems to me that this is the case. When having the Gene full on, there seems to be a "natural" slow ramp up. From what I understand, it is important to dry the beans in the first 4-5 minutes, so maybe slow down a little (max should be 150C ?). After that: full on again, until maybe 235C for City, or higher for FC+, more or less. Right?