Rerouting the ROR

[Gregr]

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. 

lol- I can identify with that! Seriously though- I've been thinking a lot about that dip and lift during and after first crack. The old dip and lift- it's what the roast does if we do nothing so it's "natural" and natural is usually good. But not always and that's what we need to nail down here. Nail down the how, as Susan is asking about and then the hard part- nail down the taste difference between the natural dip and lift and a perfectly declining RoR. Not an easy task but maybe collectively we can come to some conclusions.
The how-- in most of my roasts I see a natural dip in the RoR approximately 30-45 seconds after first crack starts. To remove the dip we need to either add some heat or increase air flow a little bit. Personally I'll opt for increasing the heat 20-30 seconds into first crack. How much and for how long will take some experimenting. And then the lift- that needs to be controlled by either lowering the heat and greatly increasing the air flow or a combo of both.
Anybody who wants to experiment with this idea let us know what you come up with along the way.

[VS]

The dip is caused by beans cracking open and releasing moisture. That being said, you want to bump up the fan to clear it which you probably would do regardless to make your roasts less smoky and clear chaff. Don't go crazy with the fan as it can draw too much air and literally suck out heat from the drum. To get this declined RoR, you do need to add heat though.

Try this - crank up the heat 10-15 second before anticipated dip. Crank up the fan at the same time as the dip starts to happen. Once things stabilize, keep the fan up but you will need to reduce heat gradually. This is much easier to achieve with 300-350g loads.

 

[SusanJoM]

Thanks Greg and VS. 

I made myself a note to up the air right after FC.  I hadn't thought to also increase the gas (which by this point is probably all the way down at .5 kPa);  I was thinking in the perforated drum the air increase would just move the heat more efficiently against the back pressure of that moisture being added to the internal atmosphere.

I'll try it in a day or so and let you know what it looks like on paper  :-))

Also:  My current/usual/normal charge weight is 350 gm.

[SusanJoM]

Well, I've got a bunch more work to do and I'm not gonna show you what happened next :-))))

[edtbjon]

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

I tried to do that in my post of May 13. I.e. I tried to describe how I go about with a typical full pound roast.

//Björn

[SusanJoM]

Thanks, Bjorn.

At about 8 minutes I'm also at about 380F, but I have been reducing the gas in increments since 325F(5 minutes) and am already down to about .75 kPa. 

[edtbjon]

Susan, I've spotted the problem you're having. Your drum is full of holes, it's leaking all over the place!
Jokes aside, this of course makes the roaster react differently to my solid drum setup. But I don't think it will be that much different. I recon that as we are (in very small steps) starting to understand what really happens to the beans the whole process is getting more clear to us.
The beans are getting through a substancial change in structure and density at 1C. They swell up to sometimes double the size, while loosing a lot of weight. (In short a very successful trip to the gym. ) You could actually say that during 1C the bean mass becomes a totally new subject to roast. As the surface of the bean(s) is larger and there is less density, it (the bean mass) will take up more heat, simply because there is more area to take the heat up. Also, as most of the water have now left the beans, the bean mass can take up heat more easily. (Please note that part of me learning this is being in this conversation right now, thinking as I type...)
I may be wrong in some of this or may have misunderstood the whole concept. But I must give it to all of you, that I feel safe in being able to develop my thoughts about this without being bashed on the head.
//Björn

[SusanJoM]

Susan, I've spotted the problem you're having. Your drum is full of holes, it's leaking all over the place!
Jokes aside, this of course makes the roaster react differently to my solid drum setup. But I don't think it will be that much different. I recon that as we are (in very small steps) starting to understand what really happens to the beans the whole process is getting more clear to us.
The beans are getting through a substancial change in structure and density at 1C. They swell up to sometimes double the size, while loosing a lot of weight. (In short a very successful trip to the gym. ) You could actually say that during 1C the bean mass becomes a totally new subject to roast. As the surface of the bean(s) is larger and there is less density, it (the bean mass) will take up more heat, simply because there is more area to take the heat up. Also, as most of the water have now left the beans, the bean mass can take up heat more easily. (Please note that part of me learning this is being in this conversation right now, thinking as I type...)
I may be wrong in some of this or may have misunderstood the whole concept. But I must give it to all of you, that I feel safe in being able to develop my thoughts about this without being bashed on the head.
//Björn

This is a lovely post.  Thank you Bjorn.  Sometimes I forget that we are ALL learning, not just me.  I'm glad Greg and I decided to put this forum up so we can all share.  Greg can share what he knows;  I get to share what I don't :-))))

I do think that the difference between the solid and perforated drums is more significant than not, but I also think that once either one of them is 'nailed' that the lessons (not the exact procedures) can probably be extrapolated from one to the other.

Susan