Roasting slow-fast profile in the KKTO

[Dimal]

G'day Al...

I don't have any blanket method for roasting either of those processing types as there is quite a lot of variability within each type. There is some info to be found however that may give you some very generalised guidelines to follow, such as this info here...
Fundamentals - Coffee Roasting - Dry Process vs. Washed Coffees

Mal.

[readeral]

I'm partly wondering about processing method. A lot of the beans I've struggled with this year have been dry processed beans, rather than wet processed. The bean I've had the most success with was the Mexico El Malinal which is a wet process.

Can anyone give me insight to my hunch?

As a result I'm thinking of picking up some Costa Rica Tarrazu San Marcos as my ongoing staple (as there is no more of the Mexico on offer - knew I should've stocked up!). Andy doesn't specify the processing method, but a quick google suggests it is washed. What do you think?

[Dimal]

the Brasil/Columbians like baseline–slower.

I usually interpret this as a gentler profile, mainly for lower grown beans...

Mal.

[DesigningByCoffee]

Matt, you suggest that the roast seemed long for the Ethiopian origin - this one is kind of the same. Dropped at 17 minutes, as my ROR was not carrying me any closer to my 218/220 target, due to evaporative cooling I suspect after first crack. However, my first crack still happened at 14 minutes, which was later than I was hoping.

Howdy
It was more that one of those Ethiopian roasts seemed so much longer than all the other origins. I tend to find that Ethiopians tend to best best when roasted from faster to baseline, then the Brasil/Columbians like baseline–slower. Just comparing all those different profiles

[readeral]

So I gave Steve82's tips a go. Seemed a lot better to me.

In a whole bunch of ways my profile _looks_ the same as my previously uploaded profiles but with the much lower environment temperature, and a slightly slower drying phase, I've definitely got a bit more aroma and fruity acidity off the freshly roasted beans when I had a munch on one.

No photos of my roasts. Unfortunately on my first Ethiopian roast my vacuum cleaner suction dropped too much to move the beans (filter problem) so a significant portion of them sat unmoving in the roasting chamber while I sorted it out... but hopefully the slightly burnt surface won't mask the flavour too much and I can make an assessment on how it improved on last weeks efforts. I also did a Rwandan and another Ethiopian with a larger batch size.

Would love comments and thoughts on this profile of the first Ethiopian batch - 470g.


One thing I wasn't sure with Steve's recommendation was whether I was ramping right from the turning point onward, or ramping from the end of drying phase. But looking at Matt's profiles and the power levels there, looks like from the get go is what I'm looking for.

Matt, you suggest that the roast seemed long for the Ethiopian origin - this one is kind of the same. Dropped at 17 minutes, as my ROR was not carrying me any closer to my 218/220 target, due to evaporative cooling I suspect after first crack. However, my first crack still happened at 14 minutes, which was later than I was hoping.

Still need to work out what is happening with my probe, and why first crack happens at 205 degrees.

One thing I'm reluctant to do is drop my batch weight any less than 470g of green (that is, 400g of roasted with 15% loss). I roast for mates, and trying to roast ~1.5-2kg of coffee on a Friday arvo when I'm resorting to only putting 400g into the roaster to begin with sounds far too painful to me.

[Dimal]

I guess you could start up a new thread and ask Javaphile if he wouldn't mind moving the relevant posts into it...

Mal.

[readeral]

Sorry I've turned this into a "how my roaster operates this week" thread, but hopefully it's a bit of relief for other KKTO owners. I'll report back on Friday or Saturday once I've had a chance to do more batches.

[readeral]

This is a pertinent observation. Have a read up on evaporative cooling in regards to " drying stage ". From what you are describing it would be a fair assumption there is lots of it going on. Definitely need to work out some kind of appropriate level of flow IN / OUT through the system.

It's _almost_ driving me to use a heat gun instead, just so I can have an opening for exhaust. We'll see what else I can just from this design first.

The evaporative cooling has been something I've been aware of for a while (ever since I started webering meat) but hadn't resolved yet. I'd been trying to avoid doing much more hole making (cutting this stainless steel really sucked!) but I think that's my only next course of action.

[readeral]

Just read through this recent discussion. I have no experience with the KKTO so can't help with specifics, but the thing that sprung to mind when I read your initial post Al was that you need to stretch the drying phase. So I can only echo the sentiments above. I know you like to read and research - have you read the articles on Coffee Shrub about stretching the roast? Could be some good info in there for you.
So it would depend on the bean, but in your position I'd be wanting to stretch the drying phase then ramp up for a definitive 1C, taking care not to let it get away on you if it's the sort of coffee that has that potential. The other considerations would be air flow and adequate exhaust/venting. Increasing airflow just around 1C would be good if that's possible on your set up.

The biggest difficulty I've had Leroy is that everything is relative, and so working out what has been subjectively described elsewhere and trying to devise a principle in which to apply to my own system has been very difficult. The advice here however has been very specific and tailored to my questions and concerns which helps me breathe a sigh of relief! Short of working with a consultant, I'd reached the limits of what I could do myself, so all this advice is very welcome.

[Dimal]

Nothing left for me to say really...
Steve and Matt have nailed what I would also suggest.
Let us know how you go Al...

The intrinsic characteristic of the KKTO to cause an extremely humid roasting environment is one I could never quite overcome and is one of the reasons why I reverted back to a Corretto at the time.

Even up where we are, some roasts literally caused pools of condensation to collect in the bottom of the roaster because there was just nowhere for it to go; even with a small gap in the top seal... I know this doesn't cause concern for all KKTO operators but it was a limiting factor for me to properly control each roast.

Mal.

[Steve82]

And that causes problems for evaporation as it gets pretty humid inside the system without intervention. There's a gap I've put in for my rubber seal which lets enough out during summer, but in winter I've been finding its too much moisture in the hot air. Releasing it needs to be done carefully otherwise the roast runs away. A slower drying phase will definitely help with managing this.

This is a pertinent observation. Have a read up on evaporative cooling in regards to " drying stage ". From what you are describing it would be a fair assumption there is lots of it going on. Definitely need to work out some kind of appropriate level of flow IN / OUT through the system.

[LeroyC]

Just read through this recent discussion. I have no experience with the KKTO so can't help with specifics, but the thing that sprung to mind when I read your initial post Al was that you need to stretch the drying phase. So I can only echo the sentiments above. I know you like to read and research - have you read the articles on Coffee Shrub about stretching the roast? Could be some good info in there for you.
So it would depend on the bean, but in your position I'd be wanting to stretch the drying phase then ramp up for a definitive 1C, taking care not to let it get away on you if it's the sort of coffee that has that potential. The other considerations would be air flow and adequate exhaust/venting. Increasing airflow just around 1C would be good if that's possible on your set up.

[readeral]

And that causes problems for evaporation as it gets pretty humid inside the system without intervention. There's a gap I've put in for my rubber seal which lets enough out during summer, but in winter I've been finding its too much moisture in the hot air. Releasing it needs to be done carefully otherwise the roast runs away. A slower drying phase will definitely help with managing this.

[readeral]

Also, after pulling the TO apart, there is almost no air transfer from outside the system in. All those vents on the side of the unit are merely for keeping the electronics up top cool. At least that's the case with my Aldi TO. It surprised us when we busted it open for mods, and I've been tempted ever since to put some sort of adjustable vent in the side of my roasting chamber.

[readeral]

Oh, I'm in Sydney Matt. No winteriness compared to your neck of the mountains. I'm just being a wuss.