Oh no! A few references to Kopi Luwak come to mind. TMI, TMI!

germantown rob wrote:My 2 cents on natural gas. The gas supply to a home is around 5"wc and my machine wanted 6-7"wc, I did resolve this by turning up the gas pressure at the main but this effects my burners on the stove a bit. It also locks you into one place to setup your roaster, not that my roaster is all that portable at 130lbs but still something to consider. On the plus side I will never run out of fuel mid roast. If I could do it again I would probably go propane and have a contract with a local company and a large tank.

Yeah, I'm glad I went with propane. A 7 gallon tank lasts me much more than 200lbs of beans which is fine at my roasting rate.

Randy G. wrote:...

I just put eight ounces of green coffee beans in my shorts to find out if you are right!

Did you get to first crack before bedtime? What about the drying phase, did you have a bowl of baked beans to help with airflow?

My understanding of infrared burners for roasting and grilling is more sales from Diedrich and grill companies. diedrich's pitch for using them is for a more uniform heating of the drum with less hot spots as well as a more efficient burning of the gas. The only experience I have with atmospheric burners is cooking on a propane grill at friends homes (I am a hardwood charcoal user at my home) and each one of these grills had their particular hot spots and cool spots over the burners.

The size of my IR burner on a 1kg machine is 5 1/4" x 7 1/4" at 8000 btu an hr at max, the burner is under the front 7 1/4" of the drum leaving 2 1/2" of the rear of the drum with nothing under it. Apparently the IR burner is the reason that the Diedrich rotates at about half the speed of other roasters, at least for the IR series. Take this with a grain of salt since I am only a user and not a manufacturer of roasters.

Randy G. wrote:...

I just put eight ounces of green coffee beans in my shorts to find out if you are right!

Glad I could help. Maybe you'll find a better test

moreshots wrote:
I was looking at an Infrared burner for the propane but hard to find a small one
Thanks Bill

Google is turning up plenty of manufacturers that seem appropriate for a 1kg+ setup. I do see many of these smaller burners are rated up to 25,000 btu an hr and mine might be as well and the 8000 btu an hr rating for the IR-1 may be the max the roaster can handle and not what the burner can emit.

flathead1 wrote:Oh no! A few references to Kopi Luwak come to mind. TMI, TMI!

I'll try to put an example. Once a body reaches a certain temperature it emits visible light. For example look at how a light bulb works. The frequency of the wave coming from a light bulb is high to a point where it is in the visible range. This frequency depends on the temperature. But what happens if the frequency is too low? The light is not visible any more (infrared=below the red color frequency). At ~ room temperature your body, like a light bulb, also emits 'light' (lower temperature-lower frequency) because it has temperature. But it is not visible by the eye. It is infrared.

Not sure if it helped

Cheers

Rob,
The ones that I am finding are longer but looking for about 16K btu and these are readily available in the circular version of a camping stove. . the inside drum will be 12" long 10" diameter with a 1-2 incha air gap at the back for the perforated drum.

getting everything ordered for the build and test.
Thanks
Bill

germantown rob wrote:Google is turning up plenty of manufacturers that seem appropriate for a 1kg+ setup. I do see many of these smaller burners are rated up to 25,000 btu an hr and mine might be as well and the 8000 btu an hr rating for the IR-1 may be the max the roaster can handle and not what the burner can emit.

germantown rob wrote:My 2 cents on natural gas. The gas supply to a home is around 5"wc and my machine wanted 6-7"wc, I did resolve this by turning up the gas pressure at the main but this effects my burners on the stove a bit.

I'm a gas-fitter. A standard low pressure meter regulator should be supplying 7" WC to the house - not 5" WC. So cranking it up to 7" was the right thing to do. Most stoves have a reg in them to drop the 7" WC to 3.5" WC (standard burner pressure), so if the burner flames changed it probably means that your 5" WC had dropped below 3.5" WC at the stove inlet from line losses. Bumping the main up to 7" should get more than 3.5" WC to the stove inlet, so the stove reg puts out the full 3.5" WC.

Thanks futz, in the back of mind I was a little worried I was putting stress on my gas appliances but you have put my mind to rest on those thoughts. My stove top burners work much better which is nice since my daughter eats pasta at least once a day and I can get a pot of water to boil much quicker even if I watch it.

moreshots wrote:Rob,
The ones that I am finding are longer but looking for about 16K btu and these are readily available in the circular version of a camping stove. . the inside drum will be 12" long 10" diameter with a 1-2 incha air gap at the back for the perforated drum.

getting everything ordered for the build and test.
Thanks
Bill

Bill,
Please post pics of your progress. What was your reasoning to go with a perforated drum? Also what material did you end up using for you drum?