HomeRoast Digest

Topic: Andy the Roaster (5 msgs / 105 lines)
1) From: Alchemist John
I have named my drum roaster Andy.
About 3 weeks ago, the 6 rpm motor on my KISS Zen II 
(www.chocolatealchemy.com/zenii.php) roaster died.  I had order a 
replacement motor some time ago, so it was time to replace it.  The 
new motor is 42 rpms.  Major difference.
Well, I wanted to report on a few major differences in the new 
roaster.  First off, I "knew" that a faster rotation speed would 
decrease my roast time given other factors remaining the same.  But 
holy-mother-of-Deityofyourchoice :O.  A 12 oz roast normally 
progresses nicely at a given power for 1st at around 10 minutes, 2nd 
at around 14-15.  This time, with pulling the power back (knowing I 
would need too) I hit first at about 6-7 minutes and had to fight 
like the devil to make it to 9 minutes before 2nd.
He is suddenly turbo charged.  So, why is this?  Can anyone give a 
concrete explanation?  I assume there is something about forced 
convections, but that is where I get stumped.  Agitation was fine 
before.  Or is it just empirical - increase speed, decrease power requirement?
Also, as it shows in the picture, I roast in a wire drum.  At 6 rpm, 
I had beans get stuck.  At 42 rpm they are moving too fast to get 
stuck.  Another great benefit.
I am going to go try 20 oz this morning and see how it behaves.  That 
was my previous limit for a good roast.
Oh, and the name Andy.  We have a short stocky "keg-on-leg" dog by 
that name.  60 lbs but only up to my knees.  He is a little 
Juggernaut and chuffs when he gets "going".  chf-chf-chf-chf.  So 
does my new drum when it has beans in it. :)
John Nanci
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.chocolatealchemy.com/

2) From: Ed Needham
I think it's just adding more energy to the equation.
Ed Needham®
"to absurdity and beyond!"http://www.homeroaster.com(include [FRIEND] in subject line to get through my SPAM filters)

3) From: Eddie Dove
I was thinking along the line of forced convection, more available energy
for transfer.
On 11/6/06, Alchemist John  wrote:

4) From: Ken Mary
This is likely one of the factors, stirring the air both inside and outside
the drum. But I believe that most of the increase is a radiant heat effect
through the wire mesh drum.
I use a non-perforated drum and recently ran some high (50) vs low (3 and 6)
rpm roasts. There was essentially no difference in my roast times with the
same heat input.

5) From: RK
  I assume there is something about forced
With drums with perforations, the higher the rpm the more the hot air 
movement in and around the beans, as you suspected added convection heat.
With my drums it usally reduces the times by 2 to 3 mins.
if you keep your temps the same as with the slower motor.

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