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NewBean
06/12/2019 3:57 PM
Just waiting on my TC4 shipment then it's roasting time

snwcmpr
06/03/2019 11:37 AM
I rarely purchase roasted coffee. I just ordered 4 bags from Mountain Air Roaster.

tm97
05/30/2019 12:34 PM
Hi, I use a wok with a glass lid for roasting. shaking the wok is a good exercise, actually.

NetriX
05/29/2019 9:08 PM
morning

snwcmpr
05/27/2019 1:56 AM
Kenya Nyeri Katogoto

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Fluidbed Bean Spouting Changes
CharcoalRoaster
I've noticed something interested with my FB roaster that just dawned on me during my roast today. At the beginning of the roast my beans spout and recirculate right up the center. However, as air heats up, beans lose moisture, the roast progresses the bean mass begins to spout and recirculate from the side along one of the bakearound walls.

My roasts aren't negatively affected ( I don't think). Anyone know why the bean mass would change spouting locations during the roast?
 
snwcmpr
My Bake-A-Round style roaster has air come up on the side, the 'other' side is an angled plate, so mine always circulate UP one side -- ACROSS -- DOWN the other side.
See Allens 1 lb build, that is my roaster.

The only variation I notice is that the beans fly higher as the roast continues, and in 1C they go even higher, until they cool down.
--------------
Backwoods Roaster
"I wish I could taste as well as I wish I could roast."

As Abraham Lincoln said "Do not trust everything you read on the internet".
 
ChicagoJohn
I have a 5" diameter glass cylinder and notice the effect you are describing where they spout up the center and back down the sides initially and then change type of motion as bulk density decreases. In mine, the entire bean mass tends to bounce up and down as pressure builds and is released, but I think the details would depend upon the symmetry of the air flow in the RC. I can't imagine there would be an effect in large enough to significantly
affect the uniformity of a roast.
So many beans; so little time....
 
Sinobi
I have noticed this as well.

Spouting in the center in the beginning
Later on spouting up the side wall of the glass.
Sometimes the sidewall up-spouting location moves randomly around during the last half of the roasting session and also centers from time to time. At other times (meaning in other roast sessions) it stays at the same side instead of moving around randomly.

I suspect that when it stays on one side, it is because the glass is tilted slightly to one side, and when it moves around randomly it is because the glass and the airflow direction is balanced.
But why it doesn't stay in the middle center all the time has made me wonder many times...
 
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greencardigan
It depends on the geometry of the roast chamber I think. My smaller roasters have the changing circulation as described, but my bigger 6" diameter one doesn't. Maybe the ratio between the chamber diameter and perforated diameter?

My thought: The flow up the wall is probably the path of least resistance (no adjacent beans returning in the opposite direction). When the bed depth gets taller, the spout has greater length to wander around, and when it hits the edge it usually stays there.
 
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