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
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
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
Just reporting the news, from here in LHC.