Here are some of my roasting profiles for larger batch roasting using Ron's 6 pound drum to a full-city to city+ roast..  Depending upon the efficiency of your grill and any modifications that you may have made, it can be very cost effective to run larger batches if you see the need.  On my Fiesta grill I have closed off near 70% of the rear exhaust vent and placed an aluminum partition inside the cavernous lid of the grill to concentrate the heat on the roasting drum.  Initially before these modifications, I would have to run both burners at full just to maintain temperature.  Now, on Ron's recommendations, I have plenty of temperature room to roast as I can roast nearly anything at 1/3 to 1/2 gas.

Before with the 4 pound drum, running the 4 pounder at its upper limit, (4 Pounds 12.8OZ green which results in 4 pounds finished roast) I would need to run at 3/4 gas to keep the roaster at 550 degrees.

However, now with the 6 pound drum, it has so much heat-absorbing metal, I can now run the same temperature at 1/2 gas on both burners. 

The thing is, with this 6 pound drum, it generates so much heat inside the chamber, that it really takes a long time to lose its acquired heat.  In fact it radiates so much heat you can back the gas down considerably.  In my case down to half.

So from my perspective, for you more commercial based roasters, it is noticeably more economical to run a 6 pounder as opposed to the 4 pounder.  Not only can you get an extra 2 pounds of coffee into the roast chamber for the same roast time, you can use much less gas as the drum radiates so much more heat.  So your output volume increases and your cost of gas goes down.

The only change to the situation, is now, it is poorer at dissipating the heat, which, in my opinion is not necessarily a bad thing.

5-6 Pound Profile

While I don't have numbers for the 5-6 pound profiles yet, I have done a 5 pound finished roast and it works pretty well.  You start to see a little un-uniformity in roast color as you start the roast with a solid 6 pounds, and end up with 5 pounds finished after water loss.  I would consider this as the maximum recommended batch size for this drum.  At six pounds, you just don't quite have the space for bean mixing.  The roast times are only extended by a minute or so.  Recommended heat should be around 575-600

I think perhaps in a crunch, this drum could manage a green load of 7Lb 3.2OZ to produce a finished 6 pound roast, and the coffee will still taste great, but I think you will begin to see some roasting defects, most noticeably the lack of uniformity in roast color.  I have pushed the 4 pound drum to  it's maximum at 4Lb 12.8OZ on a regular basis with acceptable roasts.  If you are a most discriminating roaster, you will want to avoid this overloading of the drum however for best results.

I'll get around to trying a 6 pound finished roast sometime just as a test.  I think the drum will perform admirably however.

2 Pound Roast

1. Light both burners at full gas with the drum inside to pre-heat the drum to 500 degrees.  That way, there is less to heat when you put the coffee in.  It will take less time for you to get back up to temperature.

2. Pull the drum and close the lid with the burners at high power. 

3. Using gloves, fill the drum with the greens.

4. Open the lid and load your drum filled with greens.  

5. The temperature will drop, but should come back up within 3-4 minutes.  (Any longer than this, give the gas a kick and bring the temperature up to 500.)

6. After closing the lid, back your gas down to your appropriate setting, for me it is about 1/2 gas.  Then backing down to 1/3 as the beans come to temperature.

7. After a couple of minutes the temperature will stabilize around 500.

8. First crack begins around 13:30 to 15:50. 

9. At the middle of first crack, back the gas back to idle.  Now with the 6 pound drum, it make take 3-4 minutes for the temperature to drop 25 degrees.  In this case, I will turn off one of the burners for about 30 seconds.  This will bring the temperature down 25-40 degrees or so in about 30 seconds.  This was not necessary with the 4 pound drum as the roast. (The chamber lost heat more quickly since there was less heat absorbing material on the inside). The lowest my setup will go is 470 with everything at idle.  I have to turn off a burner if I want to drop below 470 as in a 1 pound roast.  

10. Now let the roast coast on its own, using the internal absorbed heat of the system and the beans. 

11. Second crack will start around 19 mintues.  I pulled the roast at 19:30, just as second crack was beginning a full roll.

12. Dump on the cooling tray immediately and stir continuously. 

1 Pound Roast

1. Light both burners at full gas with the drum inside to pre-heat the drum to 470 degrees.  That way, there is less to heat when you put the coffee in.  It will take less time for you to get back up to temperature.

2. Pull the drum and close the lid with the burners at high power. 

3. Using gloves, fill the drum with the greens.

4. Open the lid and load your drum filled with greens.  

5. The temperature will drop, but should come back up within 3-4 minutes.  (Any longer than this, give the gas a kick and bring the temperature up to 470.)

6. After closing the lid, back your gas down to your appropriate setting, for me it is about 1/2 gas.  Then backing down to full idle as the beans come to temperature.

7. After a couple of minutes the temperature will stabilize around 470.

8. First crack begins around 10:00. 

9. At the middle of first crack, I have to cut off one burner and drop the temperature to about 430-440.  When it begins to drop below this temperature, I cut the burner back on to idle and it will stabilize at around 445-450.  Now with the 6 pound drum, it make take 3-4 minutes for the temperature to drop 25 degrees.  In this case, I will turn off one of the burners for about 30 seconds.  This will bring the temperature down 25-40 degrees or so in about 30 seconds.  This was not necessary with the 4 pound drum as the roast. (The chamber lost heat more quickly since there was less heat absorbing material on the inside). The lowest my setup will go is 470 with everything at idle.  I have to turn off a burner if I want to drop below 470 as in this 1 pound roast.  

10. Now let the roast coast on its own, using the internal absorbed heat of the system and the beans. 

11. Second crack will start around 15:40 mintues.  I pulled the roast at 16:20, just as second crack was beginning a full roll.

12. Dump on the cooling tray immediately and stir continuously. 

What a truly wonderful roasting machine this is Ron.

Thanks....

Shane Lewis