Trying to match small drum roast

[Steve]

Since starting to use the Nano I have slowly been chipping away trying to match my standard drum roast profile on the Nano or vice versa. 400g gas roaster using 250g batch size, 10 min "Rao inspired " roast.
Still a work in progress but here is where I am at with today's latest efforts, any comments or discussion have at it especially if you try the replicated profile on the Nano.

The start of the converted Nano roast ends up somewhere just in between the Ninja and Fire starter profiles. In comparison both these profiles go into a steeper ramp toward FCS and flattening out a little more after.

I have my Nano using an external fan / chaff collector / exhaust so have been trying to correlate roast markers by occasionally giving that a whiff. Not too often as I find in general even smelling the trier on the drum quite aggravating to sinus.

Some information from the drum roast which is in the KL profile Drumreplica file.

Trying to match my standard 10 min drum roast to the Nano
Start of yellow 148C BT at 4:00
Full Yellow 160C BT at 4:50
Start of orange 171C BT at 5:40
Start brown / caramelization 178C BT at 6:14
FCS 196C BT at 8:00
FCE 208C BT at 9:19
208C BT to 210C BT = smells like strong vinegar
211C BT to 213C BT = vinegar fades / sweet zone = about 18 to 21% DTR (weight loss in this zone goes from 14.8% to 16%)

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Drumreplica.kpro

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[Geronimo]

Hi

Interesting what you are trying to do. Hopefully you can answer this as you’ve had vast experience. Is it ok to do a direct conversion, because the drum roaster uses convection and conduction, and air roaster just convection. Is the end result similar so to speak with respect to roast.

Also can you please tell what beans would your drum roast profile be suitable for, and style of drink i.e. espresso?

Thanks in advance.

[Steve]

Hi

Interesting what you are trying to do. Hopefully you can answer this as you’ve had vast experience. Is it ok to do a direct conversion, because the drum roaster uses convection and conduction, and air roaster just convection. Is the end result similar so to speak with respect to roast.

Also can you please tell what beans would your drum roast profile be suitable for, and style of drink i.e. espresso?

Thanks in advance.

Hi there, thanks for your reply. Most of your questions can be answered by the following article.
https://www.roastmagazine.com/currentis ... sting.html

Basically, "industry pros" can not pick / taste the roasting system better than chance using blind triangulation when the roast is properly matched across different roasting systems and if they can, they cant tell what machine, just that its a little different. The Loring roasting machine was part of the testing and are very comparable to fluid bed, stationary drum with paddles that move the beans and recirculating hot air convection is the heat source.

My motivation is just to see if I can do something similar (why not?) and continue my learning.

The roast above will most likely be used for espresso, its well a "medium" roast what ever that means...but it can also be brewed say in a Clever dripper, which my dad of 75 years quite enjoys as he does not like super light filter roasts, which would need a different approach. Depends what flavours you value?

You could also give the above roast a bit more time for something more developed. On my small drum with small load, 25% DTR is way over developed, ashy tastes dominate.
In contrast ive found the Nano to be very good at taking roasts a bit darker without bringing in too much roasty char flavours.

The above roast is just a pre blend of 4 different beans I use often, it might work on most washed / semi washed Arabica? I dont roast low grown island coffee or Robusta.

Cheers

[Geronimo]

Hi

Good reply. And very detailed. I’ll checkout the link out also. Many thanks again.

Do you feel up to sharing your blend recipe? It’s ok if you don’t want to.

Cheers

[Angela]

We just don't know how to translate drum roast temperatures to nano 7 air roast temperatures. The only fixed point we have is First Crack temperature to make comparisons between two types.

FC fixes a difference. But all we know is that is the difference at FC.

We cannot assume the temperature difference, between types, remains the same across the whole roasting cycle.

If bean colour indicates final temperature reached, the comparison - across the roast - perhaps could be made by someone with decent (professional) gear.

Steve; your klog starts at some sub-zero temperature; cold in your shed is it?

[Steve]

Hi

Good reply. And very detailed. I’ll checkout the link out also. Many thanks again.

Do you feel up to sharing your blend recipe? It’s ok if you don’t want to.

Cheers

No worries.

It changes from time to time, at the moment:
35% washed Colombian
25% wet hulled Sulawesi
20% pulped natural Brazil
20% Honey Costa Rica

Cheers

[Geronimo]

You are a legend, and many thanks.

Will this work for milk based drinks also.

[Steve]

You are a legend, and many thanks.

Will this work for milk based drinks also.

Hah thanks, nah I am just a "man in his garage".

I find it works well for both.

Last nights effort, I have made some adjustments to the profile file in original post.
Ambient temps warming up so starting at 20C to keep everyone happy...
Small negative boost approaching first crack for the next attempt, the Nano does a pretty good job of controlling it but this correlates quite well to the drum roast where the ROR always wants to flat line or take off in an upwards trajectory.
Small positive boost toward end of the roast where I found previous attempts were dropping off quite bit.

BlendDrumreplica.klog

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[Geronimo]

Hi

To try your drum roast profile, do we export from log, or will you be posting the profile file.

Cheers

[Steve]

Hi

To try your drum roast profile, do we export from log, or will you be posting the profile file.

Cheers

Hi ive added the current version to the first post of thread.
Cheers