Jump to content

Recommended Posts

What was your wattage? I just did a roast and ran at full power until 223c and switched the dimmer in to 1130w until first crack rolling which happened at about 234c. I then moved to 1100w until fc ended (about 30 seconds) when I moved to 1080w and then 30 seconds later to 1030w until the end of the roast which was 2:30 after FC rolling. The roast is very even with very very slight signs of burning to the very tips of some beans. The roast finished just before second crack at about 232c BT (based on near identical previous roasts).

 

You say the beans burn some time after first crack and develop evenly until then...it could be poor quality greens but I think you'd see it in the development of the roast. When you didn't go over 220c what was your wattage draw?


Expobar DB Office Leva IV, La Pavoni Professional -- FOR SALE: MBK HEFT, Torr Goldfinger Titan Convex & 58.55 Flat -- Ceado E8, Lido E, Pharos VDD -- 2 and 5 cup Syphons; Vintage Nicro Metal Filter -- Gene Cafe CBR101 with Dimmer Mod and Bean Mass Probe

Share this post


Link to post
Share on other sites

That sounds like a good roast! When you run at 1130w, how long does it take to get from 223c to first crack at 234c? And at what time was your first crack and end time?

 

I have been really trying to pay attention, and see if the beans develop evenly during the roast. Some of the defects will look slightly burned quite early, but other than that the rest seem to develop quite evenly.

For the one that didn't go over 220c, I kept the dimmer on from the start and ran with a lower wattage from the start (to see if the beans were getting too much heat in the beginning). I ran at about 1150w until I hit 219, which only happened after 13 minutes due to the lower wattage.

I didn't note the wattage I lowered it to when it hit 219, but I think it was somewhere between 1050-1100.

I didn't hear first crack on these, and due very slow rise in temp, I dropped at 15:50min.

Share this post


Link to post
Share on other sites

Hearing 1st crack is essential. I am not sure about the slow rise temperature being significant as to ability to hear the crack?

 

Many people do have problems with hearing 1st. It is often due to inexperience combined with noise from the machine and other background noise. But once you have some experience, it is surprisingly easy to pick out despite the distractions.

Using a cardboard tube as hearing aid will help. I found a good place to place the tube on or near is the shoulder of the chaff box. Watch out for the moving drum---you may poke your ear out! The tube from a roll of kitchen foil is good.

An engineers stethoscope may help, ( £6 to7 of fleabay) but some people find them uncomfortable and therefore a distraction at a critical time.

Share this post


Link to post
Share on other sites
That sounds like a good roast! When you run at 1130w, how long does it take to get from 223c to first crack at 234c? And at what time was your first crack and end time?

 

I'm not sure really, I don't roast based on that kind of information anymore. I've had 5kg of this bean and roasted with a BT probe installed in the gene so I just followed the previous profiles for past roasts and get repeatable results. I only have logs for the temp measures from the probe which gives me precise times, but I don't log the gene readout temp and time anymore, only the temp at which I make changes with the dimmer. I did used to just make changes based on the BT temp but I found this lead to inconsistencies as the roast progressed through and beyond first crack.

 

I would guess somewhere around 10-11 minutes until 223c with the first pops of FC at around 13 minutes and rolling at 13:30. The roast would have finished on 16 minutes if that's the case. This information is of little use to you though as you aren't aiming for a roast this dark and you aren't using the same bean. I didn't share what I did with my roast so you could follow it, I was just describing a way to use the dimmer mod.

 

I have been really trying to pay attention, and see if the beans develop evenly during the roast. Some of the defects will look slightly burned quite early, but other than that the rest seem to develop quite evenly.

For the one that didn't go over 220c, I kept the dimmer on from the start and ran with a lower wattage from the start (to see if the beans were getting too much heat in the beginning). I ran at about 1150w until I hit 219, which only happened after 13 minutes due to the lower wattage.

I didn't note the wattage I lowered it to when it hit 219, but I think it was somewhere between 1050-1100.

I didn't hear first crack on these, and due very slow rise in temp, I dropped at 15:50min.

 

Lower power and less heat until first crack will give you a less energetic and slower crack which you might have difficulty hearing. I'm not sure what you mean by that last part re dropping at 15:50. If you aren't burning the beans early in the roast I wouldn't pull the power back as you'll just increase maillard flavours (unless you want to do that). I drop the power as late as possible to achieve whatever I'm trying to achieve: in my above profile that's a roast that has developed close to second crack and without drying out. I have tried with the same bean in the past to extend first crack, and I've also tried to extend development time beyond 2:30 and ended up with bad roasts either lacking in flavour or with bitter notes. If I were aiming for a light roast I'd want to extend first crack which means I'd be looking to limit my temp to around 230c and would have different wattage reductions rather than ones designed to carry through first and finish at a higher temp without increasing ROR.

 

Your problem right now is burning, not getting to first or controlling the roast beyond that, and not roasting for too long...scorching despite not going over 219c and despite low power draws. It might be time to post a picture of the greens.

 

Are you roasting with ducting attached? Is it a second hand roaster and if so have you cleaned it? You wouldn't be blocking the vents on the bottom with anything would you on the surface you're roasting on?

 

My voltage is always around 245 so I'm over the spec of the heater and should have to use lower wattages than you to get the same results...


Expobar DB Office Leva IV, La Pavoni Professional -- FOR SALE: MBK HEFT, Torr Goldfinger Titan Convex & 58.55 Flat -- Ceado E8, Lido E, Pharos VDD -- 2 and 5 cup Syphons; Vintage Nicro Metal Filter -- Gene Cafe CBR101 with Dimmer Mod and Bean Mass Probe

Share this post


Link to post
Share on other sites

Your problem right now is burning, not getting to first or controlling the roast beyond that, and not roasting for too long...scorching despite not going over 219c and despite low power draws. It might be time to post a picture of the greens.

You pretty much boiled it down here, what the problems are..

Here are pictures of the greens Im using:

I really only know how to look for the more visible defects - so I would have no clue what to be looking for with the beans.

 

33718027638_10a6f3c063_z.jpg

 

46870957084_a0d3028f43_z.jpg

 

46870957524_6a82a4c569_z.jpg

 

Are you roasting with ducting attached? Is it a second hand roaster and if so have you cleaned it? You wouldn't be blocking the vents on the bottom with anything would you on the surface you're roasting on?

 

Got a brand new roaster, with the large chaff collector and no extra ducting. It is standing on top of my stovetop, so there shouldnt be any blocking there.

Share this post


Link to post
Share on other sites
Posted (edited)

Do you get a lot of chaff/silverskin collecting at the air outlet grate? They look a little dark to me, maybe a few are immature? You'll be a better judge http://www.cafedecolombia.com/clientes/en/regulacion_nacional/exportadores/2831_calidades_de_exportacion/

 

What you're seeing could be the silverskin burning on the surface of the bean if it doesn't shed...

Edited by Rob1

Expobar DB Office Leva IV, La Pavoni Professional -- FOR SALE: MBK HEFT, Torr Goldfinger Titan Convex & 58.55 Flat -- Ceado E8, Lido E, Pharos VDD -- 2 and 5 cup Syphons; Vintage Nicro Metal Filter -- Gene Cafe CBR101 with Dimmer Mod and Bean Mass Probe

Share this post


Link to post
Share on other sites

Is the chaff clearer working freely? A blocked/partially blocked exit from the drum may cause an increase in drum temperature?

Some beans can be more chaffy than others.

 

At this point, a reminder to take care with the rubber buffer and not to run empty, which causes the rubber buffer to break up sooner than expected.

Share this post


Link to post
Share on other sites

There seems to be no problem with the chaff clearer, not a lot of build up there.

There does seem to be some immatures amongst the beans, but I am not that great of a judge.

 

I've now tried also roasting different batch sizes, 230g, 200g and it makes no difference on the appearance at all.

Wattage is around 1270 when dimmer is off. And I bring it down to around 1150 to keep the temp steady.

If my roasts hit 230c max, or 220c max seems to make no difference on the burning/schorching issue.

Share this post


Link to post
Share on other sites
Posted (edited)

Why keep the temp steady? Mine drops and always has after bringing the dimmer in, that doesn't mean the bean temp drops, in fact it continues to rise just at a slower rate. If you're getting burning after first crack you need to decrease the energy they are exposed to and focus on that. More information is needed regarding the profile and temps and roast progression at your different settings (i.e. is first crack duration more or less the same with the dimmer set to 1150w vs full power vs other settings (1100w? 1050w?), does it seem like first crack is taking off and you don't have control so you're struggling to slow the roast down?).

 

From the pics you've posted so far the roast doesn't appear to be really uneven just scorched and I think a lot of that is the silverskin stuck to the bean. I barely remember having beans like that myself but I would try giving them a long time to 'dry' with a low wattage setting and gene temp limit of 149c, if the skins don't shake loose from that or the normal full power (or whatever) profile after that then pass. Probably just accept it's bad greens. Maybe in another roaster you could increase airflow and blast the skins off but that isn't an option with the gene.

Edited by Rob1

Expobar DB Office Leva IV, La Pavoni Professional -- FOR SALE: MBK HEFT, Torr Goldfinger Titan Convex & 58.55 Flat -- Ceado E8, Lido E, Pharos VDD -- 2 and 5 cup Syphons; Vintage Nicro Metal Filter -- Gene Cafe CBR101 with Dimmer Mod and Bean Mass Probe

Share this post


Link to post
Share on other sites

Hey Rob, thanks again for all the input - really helps a lot.

 

Very good point about the steady temp. Something to think about there.

I think one of my (other) main issues besides the burning, is that I really struggle hearing first crack. I seem to only be able to hear it, when I roast up to about 230c and then I may only hear like 5 loud single cracks.

I've been using a tube, placed either on the exhaust or closer to the drum and it does not help me at all..

Of course this limits me greatly, as then I am really just roasting based on the color and that does me no good at the moment.

 

Here are some more pics, of one of the roast I did 2 days ago - I just cupped these and this roasted tasted the 'best'. But still has quite a lot of a charry taste to it.

 

32657156907_257bd04818.jpg46875488414_ef0186ba31.jpg

32657155727_7b02897c24.jpg46875487774_f1b156166a.jpg

Share this post


Link to post
Share on other sites

From the pics you've posted so far the roast doesn't appear to be really uneven just scorched and I think a lot of that is the silverskin stuck to the bean. I barely remember having beans like that myself but I would try giving them a long time to 'dry' with a low wattage setting and gene temp limit of 149c, if the skins don't shake loose from that or the normal full power (or whatever) profile after that then pass. Probably just accept it's bad greens. Maybe in another roaster you could increase airflow and blast the skins off but that isn't an option with the gene.

 

I will give this a go. Sometime next week, I should receive some new greens and then I will see how they behave!

Share this post


Link to post
Share on other sites
Posted (edited)

ooops

Edited by Batian
duplicate past after edit

Share this post


Link to post
Share on other sites

Just a fall back, and I am sure you would have mentioned it, but please confirm you are not pre-heating and/or letting the green beans sit still in a warm drum after another roast has been emptied?

Share this post


Link to post
Share on other sites
Just a fall back, and I am sure you would have mentioned it, but please confirm you are not pre-heating and/or letting the green beans sit still in a warm drum after another roast has been emptied?

 

No pre-heating, I cool in Gene down to 100c and cool down externally until beans are not hot.

Beans are really only in the drum, when the machine is running.

Share this post


Link to post
Share on other sites

This is what I got after cleaning the machine and the chaff collector Gene set at 220C in circa 20min plus cooling time. No burnt taste which may have been ok if I had used 20g of it but not really my sort of bean.

 

Roast1ColumbianFincaSofia.jpg

 

Colour much closer to the lighter brown some show but darker than the very light a few show. Flash and beans don't seem to work too well colour wise for me.

 

I am pretty sure they darkened more during cooling and I allowed several mins of 1st cracks so well into first crack. I used a moderately priced amplifier and mic over the end of the vent ducting to hear the cracks. A rechargeable thing off Amazon that isn't as loud as they suggest but adequate for this use.

 

Keeping the air path clean could be important but I would have thought problems would slow the roast down as the Gene's heater will spend more time off if the air flow is reduced.= less energy in ;) As I haven't actually measured the air temp though I don't know what it's doing

 

I tried this approach as the suggestions from a gent in this forum just resulted in burnt beans but I hadn't cleaned it out. Temperature set 10C higher than what I saw on an Ily video also based on this site which is concentrating on bean temperature.

 

https://legacy.sweetmarias.com/library/using-sight-to-determine-degree-of-roast

 

The site had intended to try and do something about colour accuracy but it never happened. The shot at the top where all stages are shown looks to be pretty good to me though going on my usual fresh roasted bean which is described as well into 2nd crack. The colour of them fits in well with the chart. They were more or less black from my previous supplier. I tidied the shot up a little as I feel it's better than the other bean colour charts that are about. :) Degree of brownness not the actual brown.

 

MariasRoastingChart.jpg

 

I know this has all bean sorted out but several things make me think hang on a minute so while I may finish up using the machine as others do I may find a better way of using it. I'm inclined to think for instance that preheating is essential in order to mimic conventional roasting even comparing with commercial hot air machines. How much, what temperature pass.

 

John

-


In Use Sage DB+IMS Shower Screen, Niche. Profitec T64. Others Sage BE, Mazer Mini A, Ceado 37J. Projects Little Gem, Gaggia M7D

:pToo many filter baskets - maybe. For sale when I get round to it. Robur Elect, Ceado 37J, Ascaso i_1,Piccino

Share this post


Link to post
Share on other sites

No amount of pre-heating will allow you to mimic a conventional roaster. You speed up the early part of the roast but not the later stages. The limitation of the gene is how long it takes to heat to first crack after the beans start yellowing.


Expobar DB Office Leva IV, La Pavoni Professional -- FOR SALE: MBK HEFT, Torr Goldfinger Titan Convex & 58.55 Flat -- Ceado E8, Lido E, Pharos VDD -- 2 and 5 cup Syphons; Vintage Nicro Metal Filter -- Gene Cafe CBR101 with Dimmer Mod and Bean Mass Probe

Share this post


Link to post
Share on other sites
Posted (edited)

40640540543_9efc799172_k.jpg

If it makes you feel any better this is a roast from Django coffee. I'm giving up on espresso with it but I've had it in the Sowden with no bitterness or burned flavours at all despite its mottled appearance. Some beans just develop this way even when first crack is finished. The sweet Maria's pictorial is useful but different varietals/origins can have different appearances at the same temps. If you can't hear first crack you'll be able to smell it or see it progress by the smoke coming out of the roaster. It sounds like you're hearing the start of first crack but not rolling?

Edited by Rob1

Expobar DB Office Leva IV, La Pavoni Professional -- FOR SALE: MBK HEFT, Torr Goldfinger Titan Convex & 58.55 Flat -- Ceado E8, Lido E, Pharos VDD -- 2 and 5 cup Syphons; Vintage Nicro Metal Filter -- Gene Cafe CBR101 with Dimmer Mod and Bean Mass Probe

Share this post


Link to post
Share on other sites

No. Few cracks followed by lots and then none. I did mention degree of browness not the actual colour.

 

John

-


In Use Sage DB+IMS Shower Screen, Niche. Profitec T64. Others Sage BE, Mazer Mini A, Ceado 37J. Projects Little Gem, Gaggia M7D

:pToo many filter baskets - maybe. For sale when I get round to it. Robur Elect, Ceado 37J, Ascaso i_1,Piccino

Share this post


Link to post
Share on other sites

@ajohn sorry I wasn't clear my comments were aimed at mr. karlsen AKA the op.


Expobar DB Office Leva IV, La Pavoni Professional -- FOR SALE: MBK HEFT, Torr Goldfinger Titan Convex & 58.55 Flat -- Ceado E8, Lido E, Pharos VDD -- 2 and 5 cup Syphons; Vintage Nicro Metal Filter -- Gene Cafe CBR101 with Dimmer Mod and Bean Mass Probe

Share this post


Link to post
Share on other sites

It does help a little, heh, I just need to keep at it then! Try some things out and will try some other beans too.

Won't be able to roast again before the weekend, but will give an update when I have news.

 

But yeah, still got problems hearing first crack. Sometimes hearing a few loud cracks which I assume is the start, and then I do hear a little bit after - but I think it is difficult to determine whether it is the cracks or not and for how long it goes on etc.

Share this post


Link to post
Share on other sites

If have read correctly, you are roasting inside underneath an extraction hood with no additional pipework on the large chaff collector? if so then you should also a large increase in smoke at first crack as well as a change of smell, a little more smokey / roasty than prior to first crack. If you are roasting as above then you may struggle to hear any first crack noises above the sound of the gene itself and the extractor fan so may want to try and find somewhere outside where you have a few less aural distractions.

Hope of some help and no doubt others will be able to expand on the above (one you get the hang of the power controller you will find the gene more, shall we say, how it probably should have been, much more controlled / consistent roasts)

John


Roasters: BB Dalian Amazon 1kg -Power contolled GeneCafe 101- 113Kg of greens - Tonino

Espresso: Londinium L2 - Gaggia G105 - Silvia v3 Mr.Shades PID'-d - Faema E92a2 (Project) - MyPressi Twist - VST baskets / Motta Europa (350/500/750ml) - Torr Ti 58.55 & Goldfinger flat 58.4 TiBlack, Pullman 51.4 - Acaia x2

Grinders: Flats: Compak R120 - NS Mythos plus Conics: Compak K10PB - Lido 3

Brewed: Behmor Brazen - Moccamaster KBGT471 - Aeropress - V60 - Cona model D - Clever - Mizudashi - 8-10 + 6 cup Chemex

Water: BWT Bestmax V Refrac: VST III

and a Puq Press not in a pear tree..

 

Share this post


Link to post
Share on other sites

As above, roast outside in a sheltered area with just the chaff collector, you should have no trouble hearing 1st crack.


Londinium I / Monolith Conical / Macap MC4 / Gene Cafe Roaster / Cormorant CR600 Roaster

Share this post


Link to post
Share on other sites
Posted (edited)

I thought I would give an update as I have done a lot more roasting over the past weeks.

 

I'd been roasting 3 different coffees, but still had huge problems with scorching and being unable to identify 1st crack.

Recently, I tried to go back and try an approach, which was also suggested in this thread (when I had tried it earlier on, I wasn't quite successful). I wanted to try the approach where I kind of dry out the beans at a lower temp for some time. So I let the temp rise quickly to about 140ish, and then turned on the dimmer and tried to keep the temp around 150c until I hit minute 6 (from start of the roast). Then switched the dimmer off, until I reached 1st crack and then turned the dimmer on again and set the wattage to around 1050w, until I ended the roast.

It turned out that this approach was highly successful for me. The beans got A LOT less scorching, developed much more evenly and I am now also able to identify 1st crack much more clearly (this might be due to more roasting experience though).

It has improved the taste of my coffee, as I now don't either burn, underdevelop or bake my coffee as much.

 

So, thanks for all the input in this thread. I feel I have taken my roasting game one tiny step forward.

Edited by Mr Karlsen

Share this post


Link to post
Share on other sites

Great stuff mate!

In a good roast profile you want to see an ever inclining temp at an ever declining rate of rise (RoR). You don't want to see temp stall or skyrocket at any time after turning point (TP).

Even if you track your temp by hand (e.g. every 30s), drawing a simple curve on paper will be worthwhile to see where you can still improve your technique!

 

Happy home roasting :)


says Hasi.

____________________

'This Sunday I will be out in the road saying - "Hasi says your impeading me from pursuing my recreational motivations while you wank off over the finer details of some aloof brainfork" :whistle: ' @jimbojohn55

Deep Thought says 'tight wiggles' is the answer. @Scotford

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • About:

    Coffee Forums UK is the UK's premier coffee forum Started in June 2008 by Glenn Watson, we now have more than 22000 mainly UK based members, and welcome more than 3000 members and visitors from around the world each day! With strategic investment and digital expertise from the Jackson Lockhart team (Tait Pollack and Adam Bateman), we are taking Coffee Forums UK to the next level, and are delighted to share the journey with you.

    New Members:

    We are often referred to as the friendliest forum on the web and we look forward to welcoming you onboard.

    Terms of Use

    Advertising

    Coffee Forums Media Kit

    Buy Advertising Space

    Donate

    Get Your Supporter Badge (per year)

×
×
  • Create New...