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Topic: New Convection Oven (5 msgs / 94 lines)
1) From: petzul
Seems like when I get to the thrift stores CO's are expensive. However, 
$25 for a new Flavor Wave by Hearthware isn't too bad I guess.
I toasted a frozen bagel in it this afternoon.
Less than 3 minutes froze to toasty :-) .
Okay, it is only 1225 Watts, so I am not sure it is spunky enough to 
roast coffee, and it has a wimpy fan on it.
Thought it would make a good spare!
Now I have a back up for supercharging the GG part of my Turbo Beast.
Also, with an additional 750 Watt heating element, and added insulation, 
should be able to roast net about 6 qts. , whatever that weighs.
Since the roaster bowl I use is 8 qts. Have to leave some room for airflow.
When I take it apart to beef up the insulation I will weigh the roasting 
chamber. Some energy has to be spent heating that up, as well as heating 
up the convection oven.
Probably preheating takes care of that, but I want to roast more beans 
quicker. Would be nice to net 2 lbs at a time. With only a 120v circuit.
PeterZ
Drinking more coffee now, here in LHC.

2) From: AlChemist John
There really has to be some theoretical (and practical) limit to the amount 
of coffee that can be roasted with 120v (15-20 amp) in 20 minutes or 
less.  There is only so much energy available to go into the system.  I 
have done some goggle searching, but not found what I want.  Does anyone 
know where to find heat capacities of "common" objects like, well, a coffee 
bean.  I know I could measure it, but I don't have that time or inclination 
at the moment.
Sometime around 19:31 3/2/2005, petzul typed:
<Snip>
--
John Nanci 
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.dreamsandbones.net/blog/http://www.chocolatealchemy.com/

3) From: Ken Mary
<Snip>
moment.
The real problem is balancing heat input/loss with the need for profiling. A
massive drum in a massive oven will not respond quickly to temperature
changes.
Also, the amount of coffee "roasted" depends on the quality of the end
product. You can make a drinkable 2 pound batch, but maybe only a one pound
batch will bring out the best of the bean in a particular roaster.
--

4) From: AlChemist John
Sometime around 07:44 3/3/2005, Ken Mary typed:
<Snip>
Right, that was what I meant by theoretical and practical, with that 20 
minute time constraint.  Mostly, what would be nice is just to know an 
upper limit so you don't even try to go over it.  My gut feeling is that it 
is in the 3-4 lb range, with 50% heat loses, but those are just 
guess's.  Also, if they were true, I guess it would not be highly useful 
information.  More for the sake of science.
<Snip>
--
John Nanci 
AlChemist at large
Zen Roasting , Blending & Espresso pulling by Gestalthttp://www.dreamsandbones.net/blog/http://www.chocolatealchemy.com/

5) From: Brent - SC/TO Roasting
John - This page talks about coffee beans and heat capacity. Don't
know if it answers your question, but it was informative.http://www.gardfoods.com/coffee/coffee.author.htm-- 
Brent
Roasting in an SC/TO
For a Drip/Moka/Presspot Brew
On Thu, 03 Mar 2005 06:50:53 -0800, AlChemist John  wrote:
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