Rerouting the ROR

[SusanJoM]

Okay, perforated/slow folks, how would you propose to reroute the ROR to the red line

[VS]

I am not convinced that declined ROR adds much to flavors while roasting on Huky. Right before the dip you would need to increase power and fan then slowly decrease it. This might not work unless you have strong flame and still might cause tipping/scorching. Or you could decrease your load to 350 grams.

The problem with decline is that by the time you get to development, the line has flattened to the point where achieving even 5 degrees takes a long time, which results in baking. Another option is to enter development stage at a steeper rise angle by working with lower temps early on.

Seems that everyone is trying to hit this ROR decline, but while doing so overextend development stage. To me it appears that most people bake their coffee. My suggestion - turn off RoR deltas and try to hit certain time-temp milestones. Once you know what tastes great, turn them on and try to achieve decreased ROR.

[dont70]

Sorry to be a newbie but can I ask what ROR is? And actually I haven't been able to find what MET is either. I did search for some sort of glossary and couldn't find anything so sorry if my search skills need work.
Cheers

[SusanJoM]

ROR = Rate of Rise.  The rate at which the BT (Bean Temperature) is rising.  It is the light blue line in my graph at the start of this thread.  Scott Rao (http://www.scottrao.com/Coffee-Roasters-Companion.pdf) suggests  that the best roasts display a continually declining ROR.  Whether that is the case or not, a lot of us have tried at least to make our roasts do that so we can find out.  It's a somewhat elusive goal.


MET = It's unclear what the best terminology is (Maximum Environmental Temperature is sometimes used), but in the HUKY it is the temperature of the T/C that is the farthest from the heat source.  The T/C in the upper right when you look at the front of the roaster.....just northeast of the ET (Environmental Temperature) T/C....

[SusanJoM]

I am not convinced that declined ROR adds much to flavors while roasting on Huky.

So, VS, what is it about the HUKY that would make Scott Rao's premise inapplicable?
I'm not suggesting you are incorrect.

My chasing the descending ROR is just to see if I can.  I haven't managed so far, so I have no way of knowing if Rao is right or not. 

[Johnny4lsu]

He mainly is speaking about larger roasters with higher thermal mass. Huky doesn't fit that mold.

[edtbjon]

While I can guess what you are doing, the graph only tells us what is happening. I.e. where on the dials are you from say 8 minutes and onwards.
Now, even though I use a solid drum, I don't think the pattern differs much from a pref. drum. So, I try to anticipate what is going to happen. An example would go like this (from 8 min.):

At 8 min I'm typically at 60% gas and 30% air. ~380F (I know that 1Cs is approaching within a minute. I intend to keep the fire for about a minute into 1C.)
At the very first pop (a bit before 1C really starts) I rise the air to 50-60%. I keep the heat at 50% about 40-60 sec into 1C. I then lower the heat down to 20% in increments and try to regulate the DeltaBT (i.e. RoR) with the fan. The thing is to take down the heat before the RoR starts to rise again and doing it "just about right" and not to hit the brakes with both feet. This is the hardest part of the roast, as everything is happening at once and you have to prepare for the dumping of the beans as well. (Not to mention logging the whole event in e.g. Artisan...)

IMHO, I do think that roasts benefit from a declining RoR and that it can and should be done on the Huky too. The idea of a declining RoR is still about how the heat should be administred to the beans. The closest thing to really knowing what is happening inside the bean is the BT probe, which is about the same for the Huky and a 200# roaster. Mr Rao (as far as I remember) doesn't talk much, if anything at all, on how to adjust heat and fan during the roast. He puts his focus on the RoR curve (i.e. DeltaBT). Without having experience with larger roasters, a clever guess is that I would have to plan ahead much more than with the Huky. I try to think about it like the Huky is a small quick motorcycle and the big industrial roaster is a fully loaded truck and trailer. But they should both travel the same distance at the same speed at all times, or at least most times.

[Gregr]

Well said! I've been thinking a lot about that bump that occurs shortly after first crack has finished and what can be done to meet the declining RoR everyone talks so much about. I find it very hard to achieve a smoothly declining RoR without flat-lining-- takes a lot of finesse. Good news is even with a slight increase in RoR I don't taste any baked or roasty defects. Quite the opposite- usually the shots are intense and full of flavor.

[SusanJoM]

Well said! I've been thinking a lot about that bump that occurs shortly after first crack has finished and what can be done to meet the declining RoR everyone talks so much about. I find it very hard to achieve a smoothly declining RoR without flat-lining-- takes a lot of finesse. Good news is even with a slight increase in RoR I don't taste any baked or roasty defects. Quite the opposite- usually the shots are intense and full of flavor.

It is good news, I agree, but I just can't help but wonder if it might not be even better if I could nail that curve.  I'll keep trying. 

My current roasting involves warming the roaster slowly and thoroughly at a low gas setting and a low fan setting.  I charge at about 450F and crank the gas to 3.50 kPa and start dropping the gas steadily as soon as BT hits about 320F. 

I'll keep tweaking it and keep you posted. 
I really want to see if that smoothly descending ROR is all its cracked up to be :-))))

Meanwhile everything along the way is quite delicious.

[VS]

He mainly is speaking about larger roasters with higher thermal mass. Huky doesn't fit that mold.

That is correct. Perforated drum gives beans lots of heat from convection and radiation (if shutters open). I have nothing documented and no published books. I solely rely on my tastigs from 50 something roasts on Huky. It is possible to get declined RoR, but I just don't notice it adding anything to my cup... However, it sure has sent a bunch of my roasts into baked zone.

Speaking of flavors, I brew mostly using Chemex with occasional Hario and espresso. Therefore, I look for crisp liveliness with clear flavors and low body. Always shooting for the point just past underdevelopment and vegetal notes. I have noticed that with my set up and heat, brightness and flavors get dulled when roasts extend past 9:30 min or/and development time over 1:30 min.

[SusanJoM]

Dang I wish profiles were tasteable :-))))

[VS]

I just did my first roast on a solid drum with fast motor. The temps seem to be more stable, predictable and pretty much draw this decline without purposely doing it. Not sure how other roasts will go, but I suspect it will be easier to achieve declining RoR and faster roasts.

Will see how it will taste... 

[edtbjon]

This is an interesting topic, not least as it's about the quite short and very busy part of the roast, i.e. the development phase. I do still think that a declining RoR is beneficial to the final produce.
So what are we trying to achieve? I really like fruity coffee but also a bit of depth. I find that when something tastes good quickly brewed in a Hario it also produces excellent expresso shots, so no real need for roasting different profiles for different types of drinks.
Back to Rao... He proposes a development phase which should be 20-25% of the total roasting time. To put it simplified, that should bring out all of the desireable flavour. He doesn't really touch if that goes for both e.g. a City roast and a Full City+, but let's assume that for the sake of this discussion. That makes the roasting strategies for e.g. a dried Yirgacheffe (Light City roast please... ) and a washed CentralAmerican quite different. I.e. I need to go into the light City roast with much less speed than with the CentralAm.
So, getting a nice evenly decending DeltaBT curve is what I aim for. Not easy, but doable. Now, out of having the DeltaBT racing up at the end of 1C isn't good, but I guess that having the roast stall is much worse. I do imagine that a rising RoR in the end makes flavours evaporate, leaving me with decent, but not excellent coffee. I take it none of us want baked coffee either.
This does take a lot of experience with the roaster at hand. I'm building on that and I do feel that I'm getting better results as I go (roast) along.
Do I swear by Rao's commandments. Oh, yes, I've etched them into the polished sides of my roaster... and have them imprinted on every roasted bean... No, it's a good excersise and it will make me better in controlling the roast and the roaster. At least it doesn't make my coffee bad.

[jyalpert]

Aren't we talking about trying to control a physical change during 1C?  You've got a phase change of water going on during 1C, so the chemistry of the system is behaving differently during 1C than it is before and afterward.  It seems only natural you're going to have a dip in deltaBT during first crack, and I'm not entirely sure it's detrimental to have the RoR come back up a bit afterward.

It seems like maintaining the red curve Susan drew on her chart would be very difficult considering the system "wants" to slow itself down through 1C.

Also I always interpreted the "Declining ROR" rule to be more important earlier in the roast (before 1C), and also to mean that you should be careful about your RoR later on.  Although most of what I interpret is pure BS because I have no idea what I'm doing. 

[SusanJoM]

Let's just pretend for a minute that I really really DO want to do what I asked.
Whether or not I should want to or not is not the question/issue.

I want to know how you think it would/could be done, not if you think it is the right thing to do.
I happen to be interested in how things work, and making them do what I want is how I learn.

So...
once again does anyone except VS have a way for me to get the ROR to follow the red route?