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snwcmpr
02/23/2019 9:17 AM
Ethiopian natural Gesha today .. tasting it tomorrow.

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02/13/2019 4:49 AM
Thanks again Ginny.

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02/11/2019 10:05 AM
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02/11/2019 10:01 AM
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Info On Centrifugal Roasters???
dBndbit
You know the real ultimate truth in all this?
We have found an avocation where even failure is fun.
We coffee roasters are lucky people.

MarkBart, you can be on my engineering team anytime!
Jim
11 years old... forever!
ReeferDoor.com
>home-built roasters and fair trade
 
http://www.ReeferDoor.com
seedlings
With all this, now I'm torn. I had ideas set in sand to build a new air roaster, but... this latest trend is so seductive! I'm spending a lot of time staring straight forward, looking at nothing and trying to decide.

You're right, Jim. At worst we're reduced to the great coffee we've been enjoying during deep thinking.

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
dBndbit
Sounds like you and I are in exactly the same mental state. I even have a few parts for making the air-spout roaster. But then I happened on the centrifugals... But I always seem to get stuck on the complexity. There seems to be no way to build a simple centrifugal. I want to build one, but I think I better build an air-spout first. Maybe by then I'll have gathered more understanding, and then I'll tackle all the wonderful details of a centrifugal? But heck, we know air-spouts work. Not much R&D there, no thrashing of great concepts... That and I'd kind of enjoy being the first to home-build one that really flings those beans!!!

Even the indecision is fun!
Jim
11 years old... forever!
ReeferDoor.com
>home-built roasters and fair trade
 
http://www.ReeferDoor.com
seedlings
Agreed. I got the OK today to salvage a stew pot for the "cyclone" chaff removal portion of the air roaster concept, so I'm going to keep to the air roaster for now. Monday I'll pick up the used fireplace blower (that may or may not circulate well enough) for $30.

Hopefully I won't be disqualified for prizes on any new roaster contest, but I'll enter regardless.

CHAD
Edited by seedlings on 05/10/2008 4:10 PM
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
seedlings
dBndbit wrote:
And I'm having trouble understanding the super-mixing if the beans are merely being slowed down at the rim to falling back over the rotating bed, not being scooped back toward the center in a little arc over the bed. Dang, I wish I could see the videos!!!


The more I think about it, I have trouble with it too, Jim. Could someone explain why the beans don't bunch up at the top lip of the bowl, if the air blows down the center? I've looked at the presentation and can't figure it out. And why don't those louvers grind the coffee?

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
Brainiac
Hi Guys

The vanes (airfoils, deflectors, whatever) are referred to by Probat as a "lamella ring" - which is a fancy term for a circle of vanes or blades. (The term is also used to describe the vane shape used in centrifugal fluid pumps).

There are approximately 80 vanes in the illustrated Saturn roaster - at a bowl diameter of about 10 feet, that means that the vanes are more than 4 and a half inches apart, so there shouldn't be too much risk of grinding the beans.

The vanes are compound-curved, and are also mounted into a curve on the underside of the lid - this allows them to use the momentum of the beans to turn the vertical motion (sliding up the bowl) and the rotational (horizontal) motion around, to fire the beans back toward the bottom of the bowl (which is just a truncated cone, in the pictures that have been published).

So much to learn, so little time!

Brian
Brainiac attached the following image:
bowl_flow[941].jpg
 
seedlings
Thanks, Brian. Well, that's what I thought, but something I read in this thread (that I conveniently can't find at the moment) led me to believe that the vanes at the top did NOT throw the beans back to the center, and only had to do with airflow. Since the vanes do flow the beans back to the middle, my brain is good now - firing on both cells again.

Thanks again.
CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
dBndbit
For me, the biggest part of why these roasters are so interesting is that each feature doesn't just have just one effect on the roasting. These centrifugal machines have a long list of unusual physical features, and each feature has multiple effects on the air, the beans, the heat transfer, yada, yada, yada. Everything affects everything else. We will probably never know for sure why a certain feature was originally devised. They're a cat's cradle, bag-of-worms, and Gordian knot of physics!

For instance, holes in the bowl can allow air flow through the body of the bean batch, which is great. But round holes are easily clogged by the beans, so little slots work much better. But milling a gazillion slots is a real PIA. And both holes and slots increase the surface friction which slows the beans down and causes bean abrasion. Nothing is simple, everything has to be included in a series of trade-offs. It's exactly the sort of unreasonable complexity that people like homeroasters love!
Jim
11 years old... forever!
ReeferDoor.com
>home-built roasters and fair trade
 
http://www.ReeferDoor.com
JitterzZ
cup_in_hand wrote:

I wanted to look up some info on "packed bed roasting" which is another ingenuous roasting method related to centrifugal roasters; also developed by Probat/Burns. While looking for info I came across this page.
The menus at the bottom of the page have descriptions of their roasters and the concepts behind them.
Its a slide show for a presentation, so watch for the navigation buttons on the bottom of the pages.
Great info on types of heat and how the work.


That link is broken. Here's a working link: http://www.whydon...BAT101.swf
 
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