D. Roaster Prep & Roast Profiles for All Drums

It is important to understand that each of the RK Drums (4, 6, 8 and 12) will roast with approximately the same results at a given % volume for a given temperature.  So, a 4, 6, 8 and 12 pound drum will roast the same at its 100% rated volume.  To clarify, a 4Lb Drum with 4Lbs of coffee at a given temperature will roast the same as a 8Lb drum with 8Lbs of coffee at the same temperature.

While each drum can roast more than its rated green volume, be aware that these tables may show green loads in excess of the rated load, and can be done, but will need higher than normal temperature to accommodate the extra amount of bean mass.  Beware however, that your roast uniformity may suffer slightly.

The following table works for us with most coffees and should be used as a starting point. The numbers aren’t exact, and you won’t be exactly on these numbers no matter how hard you try, but you should likely be able to hit these numbers give or take 1 minute with these temperatures and get excellent coffee.  They seem to work for most grills, and probably yours.  But if the times aren’t working out based on the scheduled temperature, you will need to adjust the heat up or down to accelerate or decelerate the roast.

To clarify, this is a starting point.  There could be other variables in setting up your roaster.  Your probe could sit higher or lower to the flames than the model used to generate the below numbers.  Your heat flow could be different and thus register higher or lower, thus it is important to understand that we must find a starting point, a profile that works on your grill/setup.  These numbers are where we start.

If you take a 4LB drum example below, roasting 4LB green.  You should be able to arrive at 1st and 2nd crack on time based upon 550-600 degrees according to the chart.  On your grill you may find that in actuality, because of the aforementioned variables that your grill is only able to deliver 1st and 2nd crack on time at at 650 degrees.  Or it could happen at a lower heat setting as well.  Our time on the first roast will be the key if we have injected enough heat into the system or not enough.

So understand that the first roasts we do on a new setup, are more like calibration roasts.  We won’t ruin any coffee, but it may not be perfect either.  We are trying to get a feel for the grill and the process.  You must learn to target a timely arrival of 1st and 2nd crack by adjusting the amount of heat you put into the system.

Please consider this article mandatory reading:

Roasting Techniques:  Roasting to target your time, not your temperature

With this understood, lets start roasting using the following charts as a starting point and then adjust the heat up or down so that we can time the arrival of 1st and 2nd accordingly.

2LB DRUM

Finished Roast Volume

Green Load

%Load

Temp

Est. 1st Crack

Est. 2nd Crack

1/2LB

9.6 OZ

25%

470

6 mins

10 mins

1Lb

1Lb 3.2 OZ

50%

500-525

9 mins

12 mins

1.5Lb

1Lb 4.8 OZ

75%

525-550

14 mins

16 mins

2Lb

2Lb 6.4 OZ

100%

550-600

16 mins

18 mins

4LB DRUM

Finished Roast Volume

Green Load

%Load

Temp

Est. 1st Crack

Est. 2nd Crack

1Lb

1Lb 3.2 OZ

25%

470

8 mins

12 mins

2Lb

2Lb 6.4 OZ

50%

500-525

11 mins

14 mins

3Lb

3Lb 9.6 OZ

75%

525-550

16 mins

18 mins

4Lb

4Lb 12.8 OZ

100%

550-600

18 mins

20 – 21 mins

6LB DRUM

Finished Roast Volume

Green Load

%Load

Temp

Est. 1st Crack

Est. 2nd Crack

1Lb

1Lb 3.2 OZ

16.6%

450-470

8 mins

10 mins

2Lb

2Lb 6.4 OZ

33.3%

470-500

12 mins

14 mins

3Lb

3Lb 9.6 OZ

50%

500-525

14 mins

16 mins

4Lb

4Lb 12.8 OZ

66.6%

525-550

16 mins

18 mins

5Lb

6Lb

83.3%

550-575

18 mins

19 mins

6Lb

7Lb 3.2 OZ

100%

575-625

19 mins

21 mins

8LB DRUM

Finished Roast Volume

Green Load

%Load

Temp

Est. 1st Crack

Est. 2nd Crack

1Lb

1Lb 3.2 OZ

12.5%

450-470

8 mins

10 mins

2Lb

2Lb 6.4 OZ

25%

470-480

10 mins

12 mins

3Lb

3Lb 9.6 OZ

37.5%

490-500

12 mins

14 mins

4Lb

4Lb 12.8 OZ

50%

500-525

14 mins

15.5 mins

5Lb

6Lb

62.5%

525-535

16 mins

17.5 mins

6Lb

7Lb 3.2 OZ

75%535-56517 mins

19 mins

7Lb

8Lb 6.4 OZ

87.5%565-58519 mins

20.5 mins

8Lb

9Lb 9.6 OZ

100%

600-625

19 mins

21 mins

12LB DRUM

Finished Roast Volume

Green Load

%Load

Temp

Est. 1st Crack

Est. 2nd Crack

1Lb

1Lb 3.2 OZ

8.3%

450-470

8 mins

10 mins

2Lb

2Lb 6.4 OZ

17%

470-480

9 mins

11 mins

3Lb

3Lb 9.6 OZ

25%

490-500

9 mins

11 mins

4Lb

4Lb 12.8 OZ

33%

500-525

10 mins

12 mins

5Lb

6Lb

42%

525-535

12 mins

14 mins

6Lb

7Lb 3.2 OZ

50%

535-565

12 mins

14 mins

7Lb

8Lb 6.4 OZ

58.3%

565-585

16 mins

17.5 mins

8Lb

9Lb 9.6 OZ

66%

600-625

16 mins

17.5 mins

9LB

10LB 12.8 OZ

75%

625-650

17 min

19 min

10LB

12LB

83%

625-650

17 min

19 min

11LB

13Lb 3.2 OZ

92%

650-675

19 min

21 min

12LB

14Lb

100%

650-675

19 min

21 min

First thing you want to do is clean your grill if you haven’t already, get the chaff and other material out of the bottom of the grill.  Take your green coffee load (I love the 5 gallon square buckets from the hardware store as you can use the corner as a pour spout to load the drum.)

Let’s pre-heat the drum and the grill.  Light your burners and set to MAX temp.  Put the drum in the grill, close the lid and close the latch.  Turn on the motor so the drum heats evenly and wait until the temperature rises close to your target temperature for the green load of your choosing.

When the temp gets close to the target temperature, turn off the motor and put on your protective glove on your unfavored hand (the hand that grabs the spit rod), open the lid, remove the drum and set the handle end on the ground and prop the coupler end up against the grill.

Close the grill lid to keep the heat in.

BE CAREFUL THE DRUM IS SUPER HOT AND WILL BURN YOU INSTANTLY.  YES IT WILL LEAVE A SCAR!