# Gene Roasting - Troubleshooting to eliminate garlic flavour coffee



## Voocash (Jan 16, 2020)

Hi there,

I would like to share my initial experience with Gene roaster and do a bit of troubleshooting? because I'm struggling to get a good roast. As you can imagine my first attempts didn't result in the best tasting coffee. I roasted 3 batches of 200g-250g and none of these made me happy yet?.

*Description of the matter:*

I purchased my Gene at BB, brand new, unmodified. I read all manuals attached and followed Dave's guidance and tips. The roasted beans look great, nice brown colour, very nicely rounded bean, perfect for a photoshoot to a magazine? however I can't tell the same about the taste. I did two cupping sessions of my coffee together with professionally roasted coffee from one of the trusted roasteries. My coffee tastes simply bad, I can taste some vegetable notes?, onion-ish?, garlic-ish, some over-roasted nut flavours?, woodiness?, hints of mushrooms, charcoal hints ?. Body is quite nice actually, smooth, milky but acidity is quite low. So overall, I wasn't very impressed, and I decided to not waste any beans and do a bit of research on this forum. After reading few topics it looks like my issues boil down to:



*?Temperature control* - a believe this can be addressed by dimmable mod which I'm investigating now, and I will be buying bits and bobs and hopefully installing it in next 2 weeks following this guide: http://coffeetime.wikidot.com/genecafedimmermod2017


*?RoR* (how quickly we get our beans to desired temp) - I think this is driven by our goal and type of beans we use. What roast level I wish to achieve and final outcome.


*?Hearing 1st crack and use it as our reference point* - I can't hear any cracks at all, it's too loud in my environment (busy road, wind, open window etc). I've got a nice advice from ?*Batian?* to use a tube to hear it better but still not much joy with this yet. I know now there is a bit of smoking happening around 1st crack so I will pay attention to the smoke level coming out of the duct and then pay a lot of attention to cracks.




Spoiler
















Spoiler














There are possibly few more factors which affects my roast that I should consider but maybe we will find them together. Let's get down to my roasting results and logs.

*My desired goal: *



?☕Light-medium roasted coffee with a nice acidity and wonderful fruity notes


*Used beans: *



Brazil, Veloso, Red Catuai, Natural from BB


Kenya, Mkumbune-Meru, Washed




Spoiler














*Tested roasting guidelines (from Daves manual): *



✔Gentle Raise - Gentle Finish


✔Gentle Raise


*Method:*



Kenyan was roasted from cold


Brazil - one batch roasted from cold, one from warmed machine (higher starting temp visible on the chart)


*Coffee beans weight:*



Brazil 1st - Green 201g / Roasted 172g (15% mass reduction)


Brazil 2nd - Green 202g / Roasted 170g (16% mass reduction)


Kenyan 3rd - Green 249g / Roasted 209g (16% mass reduction)


*Problem: *



Bad coffee taste. Flavours of *root vegetables, onion, garlic, woodiness, mushrooms, dark roasted nuts, smokiness*


Please see below the temp/time chart with specific temps. I didn't note any 1st crack because I couldn't hear it. I also dropped pictures of roasted beans.



Left - Gentle Raise/Gentle Finish


Right - Gentle Raise. Both are Brazil.


Kenyan - TBA




Spoiler
















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>>>> Temp log <<<<<

❓ Now. What you guys think about it ❓ What should I try, what temperatures or timings should I try ❓

I understand that dimm mod would help with temp control but maybe there is something I can try before I modify my roaster.

Thank you kindly for all feedback! ??
Voocash


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## MediumRoastSteam (Jul 7, 2015)

Voocash,

Have you read the Today's roast thread? You'll get a lot of insights there.

Where are you based?

Any picture of the beans? Any idea of your electricity voltage fluctuations?

Also, are you leaving your beans to rest for 10 days at least, specially if you are using with an espresso machine?

Any pictures of the roasted beans themselves?


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## Voocash (Jan 16, 2020)

@MediumRoastSteam I'm going to read it, there is a ton of knowledge there. It will take me sometime to read it 



I'm based in UK, Suffolk/Norfolk, nearby Newmarket.


I've just uploaded a picture of roasted beans. I will add Kenyan tomorrow.


I didn't check voltage fluctuations yet, but I bought the electricity meter and I will be measuring it from next batch.


I leave beans to rest for at least 3-4 days before tasting. I did cupping of Brazilian beans yesterday and they were roasted on 12/02. When it comes to drinking I only use V60 / Aeropress.


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## Rob1 (Apr 9, 2015)

As above, need to check your voltage against your heating element. They come in 230v and 240v variants.

Tasting notes suggest under development I think, and some burning. Could also have excessive maillard flavours there like fried onions, meaty, toasty etc.

200g is quite low, I'd roast 230g with something with a lot of silverskin and chaff. Increasing the mass will help bean temp increase faster which you probably want right now.

Try just running it at full power set at 235 or 240c until first crack and drop by 5-10c or 5c twice, once at the start of the beans popping and again when they stop popping then continue roasting until 2:30 from first crack start. If you can't hear the beans popping you can go off smell and smoke production. You'll notice the smell changes and then shortly after you'll probably see steam rising from the roaster and then smoke from the tube. Count that as first crack if you can't hear. You could also try roasting without the ducting over the exhaust until smoke starts coming out then you drop the ducting on there and continue.


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## Batian (Oct 23, 2017)

As above re voltage fluctuations.

Do you remember our conversation about a power meter and timing the roast to avoid high local power demand? Also, you can help by turning off high demand electrical goods in the house. ie 40" colour tv!! immersion heater, ovens etc.

Also our chat re resting with regard to brew method and roast? As suggested above, try those beans at 7 days minimum for filter and leave for at least 10 days for espresso.

How long is that exhaust pipe?

Do you remember our chat about stopping the roast some 30 seconds before you think you want to stop it to allow for the latent heat 'roasting on? Colour is important here.

If you want to pop round with your machine, on a dry day (we will be outside), I will try and steer you into hearing 1stC and try and spot what may be going wrong.


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## Voocash (Jan 16, 2020)

@Batian The exhaust duct is about 1m. I will drop you a msg, perhaps we can arrange it in the weekend.

I will use the power meter now and record the whole roasting. We will see how this will go.


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## MediumRoastSteam (Jul 7, 2015)

Voocash said:


> @MediumRoastSteam I'm going to read it, there is a ton of knowledge there. It will take me sometime to read it
> 
> 
> I'm based in UK, Suffolk/Norfolk, nearby Newmarket.
> ...


I asked where you were from because, if you were nearer me (Berks) then I would've been happy to help you out, to the extent of my little knowledge.

Looks like Batian will help you out, and, as you may know already, knows a thing or two about roasting coffee.


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## Voocash (Jan 16, 2020)

and Kenyan batch.



Spoiler


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## Voocash (Jan 16, 2020)

I'm back.

I'm still working on my dim mod which is 50% finished. I've got all the bits and fitted them in the box. I only need to open up my Gene and plug everything in.

In the meantime I roasted another batch of Kenyan beans using recommended temps and timings from @Rob1. As usual I logged the data and this time I recorded the whole process. Please find it under youtube link below. It takes almost 30min, but Youtube allows to speed videos up. *Kenya 2* is the is today's profile in comparison to previous batch. *What are you thoughts guys?* Of course can't tell much about the taste for next few days but surely will give a feedback when I cup it.

*



*








*Temps/Time LOG*


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## Rob1 (Apr 9, 2015)

First pops start at 13:10 on your video but I can't hear anything after that, no rapid popping.

Looks like it roasts very slowly and appears uneven through fc. I think you stall out first crack and then bake away. My profile was recommended if first crack progresses quickly but it looks like it would coast through at 235-240. Problem is without the dimmer mod the element will cycle on and off if you set it at 240. Hopefully you've got a 230v element installed... it's very difficult to tell when first crack stops from smell and smoke but when it starts is pretty easy. Also my advice was aimed at producing a light-medium roast (ending clear of first crack or at the end of it as that's what you said you were going for) not at the darker roast you get in the video. Either way for this it looks like you'll be ok hitting it at 240c. You'll see a bit of smoke, then shortly after a lot of it, then it'll die down a touch and that's probably when you'll want to switch to a lower temperature.

Hang on my advice was for the Brazilian wasn't it?...did you increase the batch size too?


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## Voocash (Jan 16, 2020)

@Rob1 This in fact was Kenyan Meru, washed. The batch size was 230g. 
I'm still impressed that you can hear the FC on the video  Well I think roast wasn't good, as you pointed out, it came out as mid-dark roast + unevenly roasted beans despite the fact I was aiming to have light-mid roast...

I won't be roasting anything before I finish my dimmer mod. Then I will give it a go, perhaps I can consult it with Batian before. I will post results with the mode which should be in about a week.

Assuming I have the dimmer mod fitted what would be your suggested timings and settings with it?


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## Rob1 (Apr 9, 2015)

For the Kenyan....It's a bit of a guess without roasting it myself. Roasters are different and my voltage is always over 240v so you wouldn't be able to translate directly, though if you have the 230v element your voltage might be comparable (mine is usually around 245 or 250 for the 240v element). I'd hit it with full power setting it at 240c and see what it progresses like. I'd expect first crack before 240c is reached and I'd bring the dimmer in when you can hear rolling first with a setting of about 1130w. This is based on the roast seeming to struggle to get through first crack so it looks like it needs a lot of energy to get it there and keep it going, if first crack is very rapid I'd reduce power to 1100 instead of 1130w or maybe less it depends on how I judge it, it's not really something I can say you should do just what I might do. Our voltage differences might make this all meaningless for you. Key idea would be get it to first as quickly as you can without burning or scorching and stretch first crack out to 2-2:30 mins without stalling for a lighter roast. If running it at full power scorches the beans I'd use the dimmer from about 160c on the gene. If the roast progresses unevenly I'd bring the dimmer in before it gets to the point where it starts to get uneven (whatever temp that is or whatever stage that is). I think the best thing I can advise is to run it at full power and see what happens. If first crack coasts through in 1:30-2:00 minutes and you don't have any signs of burning then ask yourself what you want to change after cupping.


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## Batian (Oct 23, 2017)

@Rob1

The Kenya Meru is this:

https://www.cafeimports.com/europe/beanology/view/munani-mikumbune-fcs-meru-aa-13758

I have only roasted it the Gene once as a sample test. Following tasting by other 'buying syndicate' members, it was deemed good enough to justify buying afloat.

Date was 16.6.19 and roasting was done outside with an ambient of 20C

Machine is a Bella Barista 240v version and is unmodified.

It was the only roast, so the charge was to a cold drum. Voltage was 241 prior to machine start.

I used, or followed as close as possible, the davecUK "Gentle Rise Gentle Finish" profile which is my 'go to' for all new coffees. Charge weight was 251gm

Temperatures are in C.

Set to 220

2 min.... 162

4 min... 195

went very bright green at approx 4.45min

6min ..... 215

8min...... 227

8.36min set to 230

9.36 min set to 235

10min.... 232

Pops of 1st C @ 11.29min

Rolling @ 11.40min

12min... 235

12.21 mins slow drop to a setting of 230

1st ended @13.35

14min... Roast stopped and normal cooling cycle started.

I described it as a light to light medium coloured roast. Weight loss was 14.74%


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## johnealey (May 19, 2014)

@VoocashI would have to say watching that video that would have to agree with the baked comment above and also reiterate the 250g in rather than 230g. I would also have gone for the gentle rise gentle finish profile and then modify out from there.

Your voltage does look a little on the low side, I used to struggle with the opposite quite often being over 250v so the power mod with the 240v heater worked well for me.

I will have a look though some old roasting logs and see if can find a comparable Kenya although, unless I did it under power mod, will be next to useless to you due to the voltage difference. Am drinking some Meru from same lot as I type and one of the recent standouts for me, bright as sweet as filter but nowhere near the level of roast you took the above to. Looking forward to the Kenya Ruiru Mills Blue Mountain.

Another visual clue that might help with spotting first crack is to look at the amount of chaff coming off and collecting around the "scraper" as sort of makes sense that this is only coming off in volume when the bean expanding at or around first crack (not from the "split" of the bean so much as the outside elements). First crack can be difficult on the gene to spot but following the advice previous (and you nose) plus visual clue should make it easier.

Best of luck

John


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## DavecUK (Aug 6, 2013)

I watched and watched and prayed for him to take it off the bloody voltage scale to watch power consumed. A great way to see what's happening. Voltage it handy before you start roasting, power (wattage) is a constant that allows one roast to replicate another, it's a constant you can manage when you have the dimmer mod (voltage isn't). Seeing voltage all the way through the roast tells you very little.

For all we know the thing could have been element switching??


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## Voocash (Jan 16, 2020)

Update.

A week ago I met with @Batian and we roasted coffee beans together. We used the same green beans which are Kenyan Meru (washed) and we used *GR/GF *roast profile. The results and summary is below:



Ambient temp 8C, initial voltage 240V and later it dropped to 235V during roast.


Wattage 1255W in the beginning and later during roast it dropped to 1235-40W


We compared two machines (mine and Batians) and spec wise they are the same although Batian's was drawing more watts ( approx 1270W)


Roast took longer then we anticipated, and we were aiming for ligh-mid/medium roast and we heard *first cracks around 16min. *


After tasting the coffee (7 days after roast) I taste similar notes as before, *over-roasted coffee with unpleasant bitterness and excessive maillard notes.*


Picture of the coffee beans will be posted tomorrow on Monday.


*We compared this roast log with Batian's previous roasts of same beans and what we noticed is that he was usually getting 30-50degC higher temperature at the same time points. Also his roasting conditions were fairly similar 8-14degC ambient. We are not sure what is the cause of this. *


Greens 249g, roasted 212g -> approx 15% reduction


Roast line - *BLUE *in comparison to previous two I did myself at home


So I'm still not sure what I'm doing wrong...









Temp log









I also created a Google Sheet with all my roasts for reference:

https://docs.google.com/spreadsheets/d/1QeD7HFFDN_SGXQjOrX2lJCKb12x4lcxupl8Ft0--yNs/edit?usp=sharing


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## Voocash (Jan 16, 2020)

Additionally I think I've managed to sort out the wiring to dimmer mod... I now need to put everything in the box and wire it to the roaster. Could someone more experienced in this check if I wired it correctly? @DavecUK @eusty @MediumRoastSteam

I tried to follow this guide: http://coffeetime.wikidot.com/genecafedimmermod2017


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## DavecUK (Aug 6, 2013)

I'll say it again you need to check for element switching, element going off and on before the set temp due to the sensor in the heater box getting too hot? (the gene is giving you clues, check it out) Can be many reasons usually airflow related.

As for the components I don't know, depends what you are trying to achieve, why you have the switch what's the box on the left for, what do they connect to and how...I know what the triac doohicky on the right is...but now idea of the design goals/schematic.....I'm sure it will be OK though...what's the worst that could happen?


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## Batian (Oct 23, 2017)

To clarify....

The only roast I have done with the Gene and the same Kenyan bean was the one posted above, in June.

The comparison roasts V referred to above showing higher temperatures at same time points between the two genes are of different beans but similar ambient temperatures and charge weights.

I take on board the @DavecUK comment re switching on and off. I confess this passed me at the time. To busy talking and watching.

I did notice V's machine was switching on and off rather quickly (?) when it reached the set temperature point. Whether it was doing so before....Guilty as charged.

I also noticed that the element could not be seen glowing red, ever. But again, my Gene took a while to glow red and was duller than what I remember.

Is the difference in power draw significant?


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## DavecUK (Aug 6, 2013)

Batian said:


> Is the difference in power draw significant?


 I don't know, so much unexpected stuff, different coffees react differently etc..i think it's difficult to actually advise... It's a moving feast. Hopefully you guys can sort it out locally.


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## MediumRoastSteam (Jul 7, 2015)

Voocash said:


> Additionally I think I've managed to sort out the wiring to dimmer mod... I now need to put everything in the box and wire it to the roaster. Could someone more experienced in this check if I wired it correctly? @DavecUK @eusty @MediumRoastSteam I tried to follow this guide: http://coffeetime.wikidot.com/genecafedimmermod2017
> 
> <img alt="image.thumb.png.43f0f7ec74ca3abc3789403ceb70e907.png" data-fileid="37274" data-src="<fileStore.core_Attachment>/monthly_2020_03/image.thumb.png.43f0f7ec74ca3abc3789403ceb70e907.png" src="https://www.coffeeforums.co.uk/applications/core/interface/js/spacer.png">


STOP!!!!!

Your digital display is For DC! Check the labels!

It should be for AC!

You plug in, it will be a pop followed by smoke.

Is your potentiometer for AC? Can you confirm?

Edit: also you should follow the UK colour coding for wiring.

Seems silly to have a yellow/green wire, thinking it's earth one day when you forget it all, and realise it's live far too late.

Same for the neutral. At least stick a sleeve around them.

All a bit pointless because we do not know which wire connect to which port/pin in the Gene.


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## Voocash (Jan 16, 2020)

Uppss... I've got these: @MediumRoastSteam

https://www.ebay.co.uk/itm/220V-2000W-AC-SCR-Electric-Voltage-Regulator-Motor-Speed-Control-Controller-Tool/174118523511?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

https://www.ebay.co.uk/itm/Digital-DC-Watt-Meter-12v-24v-48v-Voltage-Current-Battery-Monitor-Solar-Power/254103933935?ssPageName=STRK%3AMEBIDX%3AIT&var=553443570910&_trksid=p2057872.m2749.l2649

https://www.ebay.co.uk/itm/MULTICOMP-MC33523-011-91-ROCKER-SWITCH-DPDT-BLACK/181886055855?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

So I guess I need to buy this one instead:
Digital AC 20A Power Meters Monitor Volt Amp kWh Watt Cambo Energy Meter

In regards to cable and wire colours it is first ever wiring I did in my life. I have no clue about what I'm doing tbh...


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## DavecUK (Aug 6, 2013)

Yeah, does not look good to me, perhaps just connect the triac based speed controller in line with the element and see how you go. Plug the gene into a power measuring plug.

P. S. Make sure you understand how your particular scr controller needs to be connected... I'm not sure you do?


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## MediumRoastSteam (Jul 7, 2015)

Voocash said:


> Uppss... I've got these: @MediumRoastSteamhttps://www.ebay.co.uk/itm/220V-2000W-AC-SCR-Electric-Voltage-Regulator-Motor-Speed-Control-Controller-Tool/174118523511?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
> 
> https://www.ebay.co.uk/itm/Digital-DC-Watt-Meter-12v-24v-48v-Voltage-Current-Battery-Monitor-Solar-Power/254103933935?ssPageName=STRK%3AMEBIDX%3AIT&var=553443570910&_trksid=p2057872.m2749.l2649
> 
> ...


That's ok. There's always a first time.  - It was my case too. Since them I now understand a bit more of electrics and can actually wire switches and light fitting in my house.  but be careful: it's lethal. Always always take due care and appropriate safety measures!

Feel free to PM me with photos of your potentiometer. I can guide you through the wiring when you have the right components!

That A/C display seems the right one.


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## Voocash (Jan 16, 2020)

Mentioned coffee beans roasted with Batian



Spoiler




















In regards to heating element in my video you can hear when heating element is switching off at min. 13:00 -13:10

Temp is raising to 235 and once 234 changes to 235 it immediately switches off and temperature drops by 3-4deg. Is this normal?


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## Rob1 (Apr 9, 2015)

Yes so long as it only switches when the set temp is reached. Mine drops between 3-5c before switching on again.


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## Voocash (Jan 16, 2020)

*I'm back!*
First of all, I didn't finish dimmer mod yet. I was moving houses and I decided to leave it for now. In the meantime I did try to roast more beans just to experiment and achieve that light-mid roast without modding the roaster.

*What I did?*
I roasted 3 batches: Colombian x1 and Kenya AB x2. I used Gentle Raise (constant temp raise to 230degC) profile from Gene Handbook for all beans.
- With help from @Batian I learnt to recognize the First Crack. With the Colombian it was very easy, very clear cracking sound and high smoking from the tube. I roasted it for approx 1min and then ran a cooling process and discharged the coffee somewhere at 100deg and cooled it manually. 
- With Kenyan I decided to immediately discharge coffee 1min after I heard FC. It was obviously to reduce time that beans are kept in high temp environment. I decided to do it because previously I had bad results and coffee seemed to be burnt with excessive maillard notes. It was much harder to hear FC on Kenyan so I mainly relied on SMOKE from the tube. First batch was done from cold and second batch from warmed machine. Results are similar there is only that approx 40degC shift in the log.

*Results:*

*Colombian* - a bit inconsistent inhomogeneous (is this an English word?  ), not fully uniform in roast levels. I had to discard few undeveloped beans. You can see it in the picture how some beans are slightly darker than others. Taste is great, high acidity, with nice sweet aftertaste. Very Very drinkable. I currently have Squre Mile filter roast coffee and acidity levels are pretty much identical. Certainly Square Mile's are more evenly roasted but taste like I'm not far away from it, to my surprise!
This roast whilst very satisfactory and I'm considering it as my first small victory has downsides. I reckon this may be related to the limitations of the machine. Despite the fact that I managed to get this light-medium roast with high acidity and fruity refreshing taste, there is a bit of burnt charcoal notes, very subtle, in the after taste, but you can definitely sense these. The good thing is a minor problem and not affecting the cup that much. The other thing is of course uneven roast, I had to discard few beans because they didn't crack or were even still dark yellow. If I kept the coffee a bit longer I would lose the acidity so there was a bit of a trade off here.
*Kenyan *- results are very similar and it is still higher acidity very drinkable coffee with slightly more of those charcoal, burnt notes. I think you can even tell from the pictures that Kenyan beans are darker. Very chaffy, beans I have to admit. Because of early discharge many beans still kept the parchment/silverskin? I had to shake these off after roast as they were on 50% of the beans. Both batch #1 and #2 are very similar in taste and structure.

*Final words:*
Very happy with these roasts. Definitely a progress. Surely Kenyan is more difficult to roast than Colombian. I have some ideas for next batch which will be to adjust the roast temps. I will reduce the temperature to 220 for Kenyan coffee. Maybe keeping beans at slightly lower temp won't scorch them and allow beans to develop better? With Colombian I will follow the same steps with only difference to rapid discharge beans after FC. I will not use the cooling process. We will see how this goes.
Pictures and roast-log below.

*If my next batch is successful I'm willing to share the coffee with volunteers to test. Free of charge with being open to all critics. Stay tuned! *

Roast-Log 
https://docs.google.com/spreadsheets/d/1QeD7HFFDN_SGXQjOrX2lJCKb12x4lcxupl8Ft0--yNs/edit?usp=sharing

High res picture, just *Right click *and select "*Open a picture/graphic in a new window*" to see full res.


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## Lovic (Apr 10, 2019)

Great feedback ! Which quantity of beans for these roast ? 250g 230g ?

I'm surprised that you didn't change the temperature even after the FC, with my Gene Roaster, if I don't reduce it, after 1 to 1,5min there is the SC !

From my little experience on this device and in roasting (30kg until now), higher the batch quantity is, quicker the temperature raise - Depending the beans used (SHB for instance) It could be difficult to handle the power/temperature this is why I tend to manage it by reducing the batch quantity.


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## Voocash (Jan 16, 2020)

Lovic said:


> Great feedback ! Which quantity of beans for these roast ? 250g 230g ?
> 
> I'm surprised that you didn't change the temperature even after the FC, with my Gene Roaster, if I don't reduce it, after 1 to 1,5min there is the SC !
> 
> From my little experience on this device and in roasting (30kg until now), higher the batch quantity is, quicker the temperature raise - Depending the beans used (SHB for instance) It could be difficult to handle the power/temperature this is why I tend to manage it by reducing the batch quantity.


 It was 250g. You can find details in roast log I linked. 
From my experience temp did raise faster on smaller batches which is something I was expecting after reading the manual. I will only confirm it after roasting a bit more.


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