I do want to talk more about the heat issue. Do I need to move more beans? I feel like I am moving a small number of beans compared to the total bean mass and that may be part of the total issue. If it helps, I'm thinking in the theoretical sense. So what is it about a 20 pound roaster that allows the heat to stay lower? I feel like i'm not getting my question across correctly, but maybe you all will understand what i am after.

Is it an air volume issue? air pressure? cross section of beans moving?

One thought i had, is my perf plate hole density is a lot tighter then most of what i see on here.

tamarian wrote:



The movement looks right for this size and design. Asymmetrical helps with larger batches. But if the roast is progressing fine, decently controlled and gives uniform color without roast defects then it is time to put some nice beans and roast them. See how you and others like the taste, compared to same beans on a different roaster.

Weld bulk, nails and any obstructions near the perforated plated can cause fires. Some beans can get trapped and collect heat until red. If there is little movement at the bottom left, increase the angle.

If spouting is stronger in one area, make sure the roaster is level, and seal any leaks.

CoffeeInterest wrote:

Perf plate does matter, but less so with an asymmetrical chamber. You have enough clearance to accommodate the batch size you want.

You need the right blower as well. My experience has been that the Ametek 122170-18 is the best you can use.

Additionally, you probably have too much shielding around your burner to prevent a good consistency of air and flame. Brush flame torches like the Gods BP?s, the Seiverts, Exacts are absolutely perfect for this. They won?t blow out.

renatoa wrote:

You can use a flat TC, to not disturb the beans flow.

CK wrote:

Interesting concept with the flat TC, but be mindful it may be reading the metal wall temperature instead of the BT.

I do want to talk more about the heat issue. Do I need to move more beans? I feel like I am moving a small number of beans compared to the total bean mass and that may be part of the total issue. If it helps, I'm thinking in the theoretical sense. So what is it about a 20 pound roaster that allows the heat to stay lower? I feel like i'm not getting my question across correctly, but maybe you all will understand what i am after.

tamarian wrote:



I am more hands-on and find that taste trumps theory. Most theories on roasting are based on drums. Each roaster has its own characteristics. So it more important to see how does it taste?

Where did you place ET probe? Some locations may reach even higher if air flow is too high. With fluid beds you just need to initiate the circular movement and gradually decrease air flow as the roast progresses.

If you place ET probe above the beans, away from the air flow, it should not be much higher than BT. If below perforation it will a lot higher, depending on metal and thickness.

Getting rid of dead zones with steeper angle is crucial to taste (avoiding taste defects) and safety.

Adjusting perforation may help with efficiency, and possibly taste. But you need a reference point with taste, to see if any changes are worth it. But it may be easier to just adjust air flow as a starter.

pisanoal wrote:




Really sorry, I completely missed this post. I really appreciate the feedback.

With your blower recommendation, are you suggesting I'm lacking in CFM or pressure? Just looking to compare my blower to the one you recommended.

I do have a good bit of shielding around my burner, but I'm not sure id say its too much preventing the consistency you are talking about. I could see having trouble maintaining heat that way? But I have plenty of heat getting to my air stream, and it does not seem to fluctuate wildly.

renatoa wrote:

At 260?270 ?C; 500?518 ?F is cellulose melting point
https://en.wikipe.../Cellulose
His 600 F rated silicone gasket is scorching... so the degrees are there, whatever is the ET probe placed... what to say more...

These are facts, not related to drum or a specific roasting method.

It?s all about pressure when you get into the bigger loads. CFM is related, but it?s more on how well the loft motor can handle 6-10# or bouncing beans on its air bed. My first motor struggled a lot at 6lbs. The Ametek I shared easily lofts more than 22# of green.

CoffeeInterest wrote:



It?s all about pressure when you get into the bigger loads. CFM is related, but it?s more on how well the loft motor can handle 6-10# or bouncing beans on its air bed. My first motor struggled a lot at 6lbs. The Ametek I shared easily lofts more than 22# of green.

I was stuck on having enough pressure because that seems to be what people think is most important, but the pressure vs flow curve definitely comes into play when pushing the limits of the blower pressure.