Using the Gene Cafe

[KJM]

For various reasons, I now own a Gene Cafe roaster. Mine is a "new" one with the latest firmware. As a consequence, none of the net.wisdom that seems to exist for the Gene applies to my particular machine. I thought Id post my how-to for the Gene...

As a practicing scientist/engineer, I find the Gene a bit off putting compared to my PID controlled popper. There is no simple way of measuring the temperature of the beans, so you need to do that "another way". I really like engineered, repeatable processes: "Put 200g of beans in, set xxxx and away you go". To this end, Ive been experimenting

Firstly, the Gene heats up quite quickly. I have standardised my roasts at 200g. Attached is a plot of the heating (in red) and the cooling (green - more on that later). (X Axis is time in minutes, Y axis is temp in degrees C). My Gene heats up (empty) to 250C in 5 minutes. Older models take twice as long.

Secondly, the temperature displayed by the Gene is leading the bean temperature - the beans lag significantly. Setting a temperature is basically setting how fast the beans will heat, once the setpoint temperature is reached. The attached plots come from a roast of some Indian Tiger Mountain I just did and the temperature was set to 227 for the whole way up to FC and 227C was reached 5.8 minutes into the roast, but FC didnt happen until 8 minutes (exactly!) in. For me, I can reliably get FC started at 8 minutes by setting the temperature to 227C and press "go"! Works for all the beans Ive tried just lately. Changes in ambient temperature dont seem to matter a jot (probably because the beans I roast are always at about the same initial temperature).

At this point, the beans are probably close to 200C and being heated by hotter (227C) air. Winding the temperature up to 235C at this point lets me hit SC at 16minutes (FC rolls along till just shy of 10 minutes). Tweaking this down to 232C gives me a 19 minute profile (which I use for the Yemenis).

So KJMs somewhat idiot proof (or KJM-proof : ) roasting profile is:

• Put beans in. No pre-heat. No drying time, no messing about (more on this later, too)
• Set 16.5mins, 18, whatever you want your endpoint to be
• Set 227C, press go
• Wait till 10 mins have elapsed, FC is over, set next temp (235, 232, 238 whatever)

Now, in my PIDd popper I always had a 4 minute drying phase at 150C initially. I did this with the Gene too. But I havent been able to notice the difference, so the 150C initial ramp Ive just eliminated. I did 2 x 200g lots of Sidamo, one with and one without the drying phase to verify this. It was a one-off data point, so if there is convincing argument for, I can put it back in.

Thirdly (and finally!) - the Gene doesnt cool instantly (see graph). This is a PITA. Judging the 30 seconds of extra roast time. I cool to 100C and then dump the beans - out of concern for the hot Gene bits not getting too hot...

[rowdee]

Re: Using the Gene Cafe

Hey KJM thanks for this.

I gave away the 5 minute warming/drying phase awhile ago.

I am interested in your 227.

Anything lower than 229 doesnt seem to produce as good results for me. (Different machine, not sure about build as I have had it for 4 months.) My roasts recently have been 230-232 for best results.

I started using 300g batches but only use 200g now.

My problem as I have said in other threads is my hearing. I cant hear the cracks unless they are REALLY loud and so I am going on colour and smoke. But basically I tend to go on end colour and taste once they have rested. Then I can repeat which is why the Gene is so good.

When you say 8 minutes are you going on your hearing of first snaps of FC?

You mentioned about "another way" of measuring temp but you didnt tell us how/what it is, or are you patenting it?

[robertmc]

Re: Using the Gene Cafe

Thanks for your post KJM.

Im new to my GeneCafe and learning to drive it, love reading everything that people write. Thanks for your insights.

I have little to contribute other than mine does 0-250 in 5 mins. And that i notice that my freshly roasted beans are more likely to produce crema than beans bought elsewhere, even if I believe them to be freshly roasted.

And Id love to hear your ideas on how to get some idea of bean temp.

Robert

[KJM]

Re: Using the Gene Cafe

Hey KJM thanks for this.

I gave away the 5 minute warming/drying phase awhile ago.

I am interested in your 227.

Anything lower than 229 doesnt seem to produce as good results for me. (Different machine, not sure about build as I have had it for 4 months.) My roasts recently have been 230-232 for best results.

I started using 300g batches but only use 200g now.

I adopted 200g purely because that was the max the Gene can do with DP beans, and because it matches my consumption rate pretty well

My problem as I have said in other threads is my hearing. I cant hear the cracks unless they are REALLY loud and so I am going on colour and smoke. But basically I tend to go on end colour and taste once they have rested. Then I can repeat which is why the Gene is so good.

When you say 8 minutes are you going on your hearing of first snaps of FC?

You mentioned about "another way" of measuring temp but you didnt tell us how/what it is, or are you patenting it?

The 8 minutes is from a "cold" start. 10 minutes from cold, and FC is over.

I can understand your problem with the Gene and hearing the snaps. I first listened to a Gene at Hazbeans place. No problem hearing the snaps. But I do my roasting in a smallish galvo shed. A whole different ball-game! But I can still hear them!

The "other way" is no secret! It is just that I got FC at 207C with my PIDd popper; and SC at 227C. Both those temperatures are uncalibrated (but probably pretty accurate) and the popper, like the Gene, leads the bean temperature. So for me, irrespective of the temperature showing on the Gene - SC means the beans are at "227C" popper style. The graphs I attached give me an insight into how quickly the thing heats up and successfully transfers heat into the beans - I can get the beans to 207C (Popper equivalent temp - not the real temp!).

So frobbing the temperature up a bit and assuming the thing is reasonably linear means you can predict temperature ramps to your desired end-point etc. But its all very indirect - a direct measurement of the bean temperature would be nice!

And the 227 vs 229 or similar probably dont make much difference - my Gene shows the same temperature as my thermocouple/DMM. Hazbeans shows temperatures 5C higher than they are (at room temperatures, at least). So your 229 is probably the same as my 227...

Anyway - Ill continue to tinker at the edges and report anything I find back!

Cheers
/Kevin

[KJM]

Re: Using the Gene Cafe

Thanks for your post KJM.

Im new to my GeneCafe and learning to drive it, love reading everything that people write. Thanks for your insights.

I have little to contribute other than mine does 0-250 in 5 mins. And that i notice that my freshly roasted beans are more likely to produce crema than beans bought elsewhere, even if I believe them to be freshly roasted.

0-250 in 5 mins. I really got a laugh when I read that. I just finished watching Top-Gear. 8-) Sounds like yours is just like mine, so we can exchange profiles without too much brain power...

And Id love to hear your ideas on how to get some idea of bean temp.

Robert

Sadly, it isnt "direct". As I replied to rowdee - I just upped the temperature to 235C at FC (which for me is 207C) and then timed SC (227C) so I get a particular temperature ramp. Fiddling the temperature fiddles the ramp rate. So my bean thermometer is a timer

Sorry, no magic answer!

Cheers
/Kevin

[rowdee]

Re: Using the Gene Cafe

Thanks Kevin,

I tried your 227 versus my 232 on the weekend with two roasts of the same blend so will let you know later in the week what the cupping is like. (I purposely chose Dominicans with a huge FC so I could hear them.)

I gave half of each roast to a friend and have asked for cupping notes as well so it should be interesting to compare.

[KJM]

Re: Using the Gene Cafe

Ahh - a blind tasting! Way to go.

I suspect there wont be much of a difference - do you know how long it took to get to FC with the 232C setting?

Talking to Greg Pullman at work today I decided I should put in the extra time and effort to work through some different temperature settings to figure out what temperature ramps I can actually achieve. Again, itll vary for pretty much each roaster - but it should be close. Given my rate of consumption, however, itll be a while before I can get the data. Pity the manufacturer doesnt do this for us!

/Kevin

[rowdee]

Re: Using the Gene Cafe

I suspect there wont be much of a difference - do you know how long it took to get to FC with the 232C setting?

No, sorry, that is the problem with being deaf, (slightly hearing impaired), I could hear it once it was going, which was about 12-13, but no way I could hear it when it started. I was interested in your 8 minutes, at least that gives me a guide to listen as closely as possible.

That is the thing I miss about the bm, at least I could hear both cracks from their beginning without any trouble at all.

[rowdee]

Re: Using the Gene Cafe

Now here is an interesting experience which illustrates why it would be good to measure actual temps of the bean.

Roasted up the last of my MTC Boomerangs yesterday. Imagine my surprise when I started to hear fc at 198 on the Gene and at 7 minutes, accompanied by a huge puff of smoke. Couldnt believe, that I could hear fc but more than that, that it was at 198. Never had that happen before. Could hear second crack as well and another big puff of smoke, pulled the roast at 15 minutes, which I have never done before either. (Roast setting was 232/19)

Only about a 7 on the CS scale but they had certainly hit rolling sc.

So I then did a second roast with my favourite African and changed the setting from 232 to 229 and everything went as usual, couldnt hear fc until around 13 and pulled roast at 19 minutes for a 9 result.

Certainly interesting.

[smoky]

Re: Using the Gene Cafe

Have been using the Gene` Cafe for some time now, and have had great success from it. My settings are for most beans 230c at 18 to 19 minutes, 1st crack heard at approx 12 to 13 minutes, but no puff of smoke, never had that happen yet.

Have tried different temps but 230c seems to be the medium for the beans I roast, although two of the beans I have defy this, one has to roasted at 235c for 19mins and the other at 230 for 17.5 minutes to have the best taste emanate from the beans when consumed.

Puffs of smoke, nope, but tell you this, was kicked out of the kitchen to the back porch with the machine because of the slow smoking out of the house.... ;D

Love the machine, and like rowdee I went from 300g to 250g, mainly because of the bags, they just fit 250g in them.

Keep the good coffee comin man!

[rowdee]

Re: Using the Gene Cafe

Yes smoky as I said I have found 232/19 to be about right for me for most roasts.

I have recently moved outdoors for the roasting which enables me to hear the cracks better. I was roasting under a range hood which was great for the smoke, etc but not good for the hearing.

;D

[smoky]

Re: Using the Gene Cafe

Like you Geoff, yes, moving outside enabled me to hear the cracks, which isnt easy with the Gene at best of times, for me anyway, having industrial deafness, have to have me ear that close it cooks as well as the beans... ;D

[speleomike]

Re: Using the Gene Cafe

Hey guys

Like you I place my ear close to the outlet of the Gene Cafe.
Just make sure you swap ears occasionally so any hair is burnt off both sides of the face evenly. It looks silly otherwise :-)

Mike

[Thundergod]

Re: Using the Gene Cafe

Thats why I dont have a Gene.
Being totally deaf in one ear Id have to burn the other side just for appearance sake.

[Myrtle]

Re: Using the Gene Cafe

Wasnt too sure where to put this - seems as good as any spot.

Yesterday, on the advice of fellow Gene owners, we decided to pull apart the chaff collector and clean the mesh screens - both of which were probably 2/3rds blocked with "chaffy" bits.

The subsequent roasts, which I left for the usual time, which of late have been around the 21min mark, were a lot darker than what we typically get & had lots of divots (I think thats the term?). When I weighed them the loss of moisture was also a lot higher - around 21% instead of 17-18%.

All suggesting that prior to cleaning the air flow through the gene was a lot less! I had noticed my roast times had extended out from 18mins to the 21min mark, but had put it down to the cooler temps at the moment!

My advice - if you arent already doing it, clean the mesh screens out occassionally. My gene is about 20 months old, so its probably not something that needs weekly attention - but perhaps every few months! I have heard of the screens getting totally blocked, and ultimately resulting in blowing the element!

Note that the second screen does need to be cleaned also - mine was partially blocked with lots of fine stuff that had got through the first screen.