HomeRoast Digest


Topic: upgrade of P1 (4 msgs / 96 lines)
1) From: petzul
Today it is raining here in Lake Havasu City, AZ; a cooler day than 
usual for roasting coffee.
Yesterday I had added a ring of Hi Temp silicon sealant around the 
outside of  the chamber of my P1, and another ring around the outside of 
a candle chimney (both ends are the same diameter and the middle is much 
wider) a skosh bigger than the chamber. I put the two together with a 
screw clamp and fired her up. (Usually I use a lamp chimney that just 
fits inside the chamber, this chimney is almost twice the volume.)
Since the temp outside is below 70F I let the unit heat up to 300F, 
before I turned off the heat, throttled back the air flow, and added 250 
Gr. of green coffee.
It was sort of a struggle for the P1 to circulate this mass at first. 
Had to turn the fan voltage up to about 132V.
Scary there, don't know how much it will take and I would hate to burn 
out the fan.
In a few minutes though the beans were bouncing around nicely and I had 
to turn down the air as quite a few were flying out into the yard!
I kept the heater at 121 Volts and did not burn anything. Got to 300F at 
just about 3 Minutes and first crack at 6 minutes (whew). By now the 
glass is a little less than half full because of the bean expansion, and 
I have to keep cutting back the air to try to keep some beans inside to 
finish the roast! Seems like a storm of them is flying out!
I cut back the heater to 119V and  coasted into second crack at about 12 
minutes. Cut off the heater and lowered the fan even more.. cooled to 
below 200F in about 2 and a half minutes.
The beans smell fine, and the roast looks even.
This is scary though as it seems to be abusive of the trusty P1.
In a little while I roasted 200Gr with the same setup. Needed much less 
power on the air and heat.
200 Grams is a walk in the park, hardly lost any beans out the top, as 
is usual.
With 250Gr there is too much loss, although the final weight ended up at 
204 Gr. I guess that is not too bad after all, I just hate to waste 
coffee ;)
May still try experimenting with an even larger chamber. It seems like 
if the chamber is belled out in the middle and necked down at the top 
there is not much heat loss. When I tried with cone shape, or even a 
straight cylinder, there would be too much heat loss to roast much over 
120 Grams.
PeterZ
Just reporting the news, from here in LHC.
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2) From: miKe mcKoffee
What about maybe covering the chimney with a coarse screen to keep the beans
in and or a can extension to add more height?
Kona Konnaisseur miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc.http://mdmint.home.comcast.net/coffee/Rosto_mod.htm

3) From: Ben Treichel
Taller chimney, I can push 300, but 255 works good.
petzul wrote:
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4) From: AlChemist John
I roast with a metal cone.  The beans need a vertical trajectory to get out 
and just don't achieve that.
   \       /
   | \    / |
   |        |
And if they do make it out, they still just slide right back in.
Sometime around 01:31 PM 10/27/2004, miKe mcKoffee typed:
<Snip>
--
John Nanci 
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.dreamsandbones.net/blog/http://www.chocolatealchemy.com/


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