BBQ roaster - general info

[deco0028]

Thanks for all your time on this Fatboy, very educational and very inspiring.

Thanks Brett

[Aaron4820]

Thanks for all your time on this Fatboy, very educational and very inspiring.

I second this.

[Ravenscroft]

Thanks for all your time on this Fatboy, very educational and very inspiring.

[fatboy_1999]

The rod I use extends out about 500mm longer than the BBQ, so one end of the rod is not hot when ready to dump beans.
For the other part of the rod, I have a welding glove with some extra heat resistant material added (cut up another glove and sewed it on top basically).
The drum has a spring latch that is fairly easy to flip up with the glove on.
So my dumping process is:
Start both my bean coolers up (ceiling fans in white plastic tubs with mesh sieves on top).
Lift BBQ lid.
Remove motor from rod.
Undo latch.
Grab both ends of rotisserie rod - making sure to have the glove on the correct hand!
Dump half roast into cooler 1
Dump the other half into cooler 2
Return rotisserie to BBQ - ready for next roast or to cool down for packing up.
Stir beans in coolers with wooden spoon.
When the beans are cool enough, I take them into the shed for bagging.

Yes, you need to be careful, but thus far I have only had 1 'medium' incident and a few very minor ones.
Medium incident was setting fire to a roast in the early days. Got distracted and had to hose down the drum and lose the beans.
Minor incidents are spillages. Sometimes on load, sometimes on dump, but never too bad.

[brettreaby]

just wondering how you dump the beans: still on the rotisserie rod? i would have thought everything would be pretty hot and you have to be careful?

[fatboy_1999]

I usually roast around 1875g green. Yields around 1500g roasted.
Roast times - Depending on the bean and other factors like the weather (as I am outside), 1st crack between 14m and 17m mark, 2nd crack between 16m and 19m mark.
Very rare for my roast to go past the 20 minute mark these days.
I roast most beans to just on 2nd crack. I don't personally do a lot of lighter roasts, but as long as your BBQ heat source is quickly adjustable, then I see no reason why you cannot control the profile quite closely.
The important thing is to take notes.

My main learning curve on the BBQ has been handling the thermal mass. When I went to the larger drum, I had a few roasts run away from me (1st crack pretty much right into 2nd) as I was not reducing the heat early enough and the heat within the beans took things along faster than I wanted.
I have got a handle on that these days - basically I reduce heat to low on all burners when 1st crack begins and the roast will progress to 2nd with little further intervention.

There are also some roasting styles or methods that you can look at. EG: Ramping up the heat to full again shortly prior to finishing the roast.
There are some training courses out there that you can take that explain profiling and other aspects of roasting in more detail - could be worth looking into that.

Was the RK drum worth the outlay? To me it certainly was. I'm more than happy with my results, and there are a few family members and friends who also seem pretty content with my output.

Brett.

[Aaron4820]

Thanks for that - that's great getting bronze medal. What sort of roast times to 1st and 2nd crack do you generally get (for arguments sake, say for a small hard African bean or a large green Colombian bean?) Can you roast beans on the lighter side (my preference) in a way that retains brightness whilst still highlighting a beans individual flavour? Thanks again.

PS. I was contemplating buying an RK drum for use in the gas BBQ. But I have been unsure whether the results would be worth the outlay. I appreciate your thoughts.

[fatboy_1999]

@Aaron4820 - I think the BBQ drum roasts as well as any of the other main methods.
I find I have pretty good control, but then again I have been doing it for around 13 years.
The only down side I can see is if you wish to use the roast monitor software and temperature probe, then the drum does not lend itself to an easy solution for getting the temperature probe into the bean mass, whereas a Coretto and Behmor does.

For whatever it's worth, I won a couple of bronze medals at the last Golden Bean with my BBQ roasts.

Brett.

[noonar]

Genaeral Answer here... Coretto.

[Aaron4820]

At the risk of getting a very general answer back, may I ask how well the RK drum and BBQ setup does in terms of quality of beans roasted? What ends up in the cup? Or what can you do once you learn how to roast on such a setup? I imagine it is largely down to the user? Any thoughts are welcome. Thanks

[fatboy_1999]

Improve the roast quality from what?

I think putting it a convection oven would decrease your control and visibility.

And unless you had very good quality exhaust ventilation for your oven, it would be a no go in my book. Too much smoke is produced during the roasting process.

As for the chaff, well that's a whole other problem. Purpose built roasters like the Behmor have a chaff collector, but once you start looking to roast bigger batches, you get bigger amounts of chaff.

If you are roasting in a drum, then it will retain a significant amount of the chaff.

Some will burn off during the roast, but I find the bulk of it is blown off the beans after I dump them into the cooler.

And of course, some beans produce much more chaff than others.

[habahabanero]

Thanks ,but I am not the sort of guy who could work out torque if it was telling me the equation of the meaning of life, to which I believe incidentally the answer to be 42.

But thanks for your on going input as it sort of helps me in the idiot disposition in which I find myself stumbling about.

Torque is a linear equation - so a simple division/multiplication calculation. Expressed as kgf.cm (kilogram force per cm) or Nm (Newton meter) - conversion calculators are your friend. The only difficult bit is calculating what % of your roast is contributing to the torque - depends on size of any vanes, drum material, drum orientation etc. - it's not the whole weight of your roast. The torque required is that weight in kg multiplied by the distance from the axis in cm.

I recently replaced the drill that was running my roaster with a 13kgf.cm 50rpm 12V geared motor bought off evilbay - future proofed in case I want to build a bigger drum. The torque I needed was only about 0.8kgf.cm for a 300g roast in a 16cm drum.

[deco0028]

Hi all
Would a convection function on a home BBQ improve the roast quality? Also, any ideas on how to ventilate to collect the chaff while roasting?

[Ravenscroft]

Thanks ,but I am not the sort of guy who could work out torque if it was telling me the equation of the meaning of life, to which I believe incidentally the answer to be 42.

But thanks for your on going input as it sort of helps me in the idiot disposition in which I find myself stumbling about.

[fatboy_1999]

I've never tried one, but I think the slow rotisserie motors wouldn't cut it for roasting. They are usually around 3 rpm.
My wiper motor was around 55rpm when I got it. It has slowed down to around 45rpm over the years, but given its workload, I think it has done a stellar job.
My backup motor works fine for my original (1kg) drum, but cannot handle the 2kg drum. So depending on the capacity you are wanting to turn, you will need to work out the torque required and see if you can source an appropriate motor.
There are items on various sale sites called 'wondermotor' which look amazingly like a wiper motor, but seem to have an actual torque rating, so they might be worth looking at.

I did try to figure out my torque requirement a little while back but got somewhat sidetracked. I'd like a simple "Can handle 5kgs" rating, but torque isn't as simple as that according to all the calculation sites I ended up at.

Good luck.