Pimp my Corretto - the Splitter

[DesigningByCoffee]

Hi all
Another weekend of busy development in the DBC shed
The theory is that this splitter divides the hot air coming into the MB pan & directs around 1/3 of it down under/into the beans, rather than just hitting the top of the bean mass. Im also hoping that it might stir up some of the chaff being retained underneath, and blow it up to the surface and out using the usual airflow.
Its one of those mods than Im quite sceptical of having any great benefit, but it was a great morning tinkering nonetheless! If there are any Newtonian moments with this one, then watch this space - I wont be roasting again till later this will, so Ill have to put off the follow up for a bit.

Happy roasting in the meantime!

Matt

[DesigningByCoffee]

Re: Pimp my Corretto - the Splitter

Newtonian moments

it may well be!

Did a roast tonight. 350g Cuban. Took to 223 degrees - just into 2C. Very good, smooth profile, but still quite similar to many Ive done before. But what shocked me was the aroma! Beautiful roasting aromas during the roast, and the smell when the beans hit the bean cooler (it was a nice still night) was absolutely spectacular - Ive never actually got any hint of aroma venting from the cooler before.
But what was most amazing was the BM pan. When tidying up at the end of the session, after the pan had pretty much cooled, I took a whiff inside the pan - and got a huge hit of - wait for it - caramelised peach with vanilla! If only I could have bottled it! Normally I get a bit of oily/roasty/burny smell - but not a hint of that tonight - more like dessert at Zumbos!
Anyway, dont know if I can claim the new splitter actually aided airflow as intended giving a more even roast throughout the bean mass as intended - that will depend on whether I can repeat the performance next roast I suppose!

But now Ive got to wait a week to see it in the cup :-/ - will report back!
Matt

[Dimal]

Re: Pimp my Corretto - the Splitter

Sounds great Matt.... [smiley=thumbsup.gif]

Definitely encouragement to stick with it for a while. Will certainly be looking forward to your cupping impressions in a few days.

Something Ive been thinking about, is to run a short extension directly from the heatgun nozzle, straight into the side of the BM/Pan. Just a cm or so up from the bottom of the Pan. The intention was to direct the hot air straight into the bean mass rather than in from the top of the Pan. A piece of 3.2mm s/s mesh across the hole to prevent the beans from falling out of the Pan, and it should work in a similar way I reckon.

Will get around to it one of these days.... :

Mal.

[DesigningByCoffee]

Re: Pimp my Corretto - the Splitter

Thanks Mal
It was certainly exciting! Im still leaning towards the snake oil end of the spectrum for the splitter - it probably had more to do improving technique

But having reflected over the past couple of days, Ive thought of a few possible additional benefits.
I was actually pondering a similar option to the one you suggested while developing this one, maybe running an inlet pipe down the outside of the pan then in through the side down near the bottom, covered with mesh. But the space was looking quite tight to do without serious panel work! But then I managed to scavenge a few sheets of this perfd aluminium from a clients scrap bin, so this idea took shape.
On top of the potential benefits of added airflow to the bottom of the bean mass, Im wondering if the splitter panel, centred in the HG airflow, actually heats up and acts as a radiant heater panel too? The sides of the pan would never heat up to this degree to give off much radiant - but this would. And as commercial roasters seem to have a radiant/air mix, maybe this might produce some of that effect?
The shape of this design also reduces the distance to the paddle - so the beans actually speed up through this narrower gap (I watched it pre-roast to check the bean flow). This could prevent scorching from the panel & direct gun blast.
It also still allows for a fair degree of hot air to still gently heat the remaining beans in the pan in goodly corretto fashion - I wondered after if a single entry point under/directly into the bean mass would leave a cold corner somewhere else, or create hot-spot roasting more like a popper?

Just random musing really - but from the results of that roasting experience (I have never experienced anything quite like it before!) Im happy to muse!

Cupping is still a few days away - but the valve aromas are promising!

Have a great day
Matt

[chookdoyle]

Re: Pimp my Corretto - the Splitter

Looks Great Matt!
Have you found that with the bulk of the hot air entering the bottom of the pan and coming up through the beans, and not so much pushing down on the bean mass, that its harder to retain the heat in the pan?

Love the idea though, keen to see it in action!!

Liam

[DesigningByCoffee]

Re: Pimp my Corretto - the Splitter

Liam Doyle…
Wondered if I might meet you here one day You have turned to the dark side, havent you! Coming out west this Christmas? :

With the insulation for the pan and the cover over the top I havent noticed much temp drop in the main pan overall - the data from my DMM followed fairly closely my normal profile. Also, only about 1/3 of the HG airflow actually goes down past the splitter - so most of it still hits the bean mass/warms the main pan directly.

But it certainly gave a really smooth roast

You still on the BBQ?

Matt

[chookdoyle]

Re: Pimp my Corretto - the Splitter

Fair enough with the air flow - makes sense - I really like the design.
Were actually heading to england for 2 months over Christmas to be with Lucys family!!

I have definitely been corrupted, been roasting for 20mths now on my flowerpot KKTO (the build thread is on here - but Ive made some changes since then!)- averaging about 2.5kg a week... loving it

So.... Im planning to build my first corretto in England!! Im lining up to buy a machine a grinder over there to sell when I leave (I mean seriously - 2 months is a long time!!), and what better way to spend some time of my holidays than experimenting around and building a new roaster!!

Be good to catch up soon!

[DesigningByCoffee]

Re: Pimp my Corretto - the Splitter

and what better way to spend some time of my holidays than experimenting around and building a new roaster!!

Fair enough too! Ill have to read up on the Flowerpot roaster. But 2.5kg a week - either youre drinking waaaaayyyyy to much at breakfast or still getting other poor students through Greek on the side ;D
Enjoy your holiday & time with the fam! I was going to see if you wanted to take over the DBC shed for a few weeks… but the UKll do - and from the sound of the coffee over there you might end up with a job!

Catch ya soon
Matt

[DesigningByCoffee]

Re: Pimp my Corretto - the Splitter

Hi all
Just an update on the splitter development - its moving away from snake-oil and getting into the jolly thought provoking end of the spectrum!
Did another roast tonight - with a completely different bean blend (Cuban + Brazil + Uru) and got the same beautiful fruity aromas coming from the bean cooler and the pan post roast. I should be breaking into the previous batch in the next day or two, which has now been resting 5 days - so well see how it cups.
But does anyone else gets these types of fruity aromas during/after the roast? Could it be some of the bean oils? :-? Anyway - Im loving it - but would be interested if anyone else has these experiences in any other roasting setups? Maybe Ive just hit the sweet spot in my setup - but I dont have any other experiences to comapre it too.

Happy roasting!

Matt

[DesigningByCoffee]

Re: Pimp my Corretto - the Splitter

I should be breaking into the previous batch in the next day or two, which has now been resting 5 days - so well see how it cups.

Well, starting to get the first splitter batch working its way through the hopper in my doppio this morning - and the results were as spectacular as the aroma suggested! Still a pretty lively pour at this stage, but the flavours & aromas were nothing short of mind-bending.
Im just amazed that even though I maintained the same basic technique / beans / & profile, adding in the splitter has transformed my roasts from getting pretty good now to like nothing Ive ever tasted before!
As you can tell, Im totally thrilled with the results. Im still reasonably new to roasting (only 40-50 batches down so far) so I havent the wide ranging experience to compare these results with longer term tweaking to a normal un-modded corretto - but Id be really interested to see if a seasoned corretto jockey would notice any difference with a similar mod?
Anyway, if anyone is interested in pottering, Ive included here a template that I developed for shaping the splitter to suit a Breville BBM100 pan (the curves etc made it quite hard to fit without gaps where beans can get lodged, so this involved a few revisions) and the best thing about it is that it can always be removed if it doesnt work (bar few small rivet holes )
PS I imagine this could also be done with SS mesh, tin with holes punched etc etc. Ive used some perfed aluminium, but Ive still drilled extra holes… so should work with what ever is on hand!


Matt

[DesigningByCoffee]

Re: Pimp my Corretto - the Splitter

Interesting seeing the development over time (now that Ive been through a bag or two) - with the splitter in place. While these roasts are certainly much richer in flavour & aroma than previous roasts, they also much more fickle in the grinder & machine.
While previous roasts could be ground down and pours slowed to almost obscene degree without degradation, and in fact needed to be to get maximum strength & flavour, these roasts very quickly turn bitter when ground fine. In fact, Im back to quite coarse grind/fast pours (much closer to the 25sec rule than previously).
Not sure if this has to do with a deeper roast internally in the beans (despite almost identical profile & dump temp) - any seasoned roasters know what those cupping results could show in terms of roasting depth?

Cheers all
Matt

[philschl]

Re: Pimp my Corretto - the Splitter

Ive so far done 10 saucepan roasts and am about to move to a popper but have also started looking out for coretto parts. This thread puts a whole new dimension on the coretto concept! Isnt it amazing how the Internet has enabled information to be shared so that total laypeople such as myself get to roast their own coffee at home. 8-)

[DesigningByCoffee]

Re: Pimp my Corretto - the Splitter

Great fun - isnt it!
And every little step adds a whole new dimension… be waiting with bated breath to hear about your popper & coretto journey!
Matt