Roasting Profiles for RK Drums

To roast excellent coffee, the beans need to finish roasting in a set amount of time. If it takes too long to get to 2nd crack, it’s just not going to taste very good. The time will vary depending on the size of the drum and the percentage load of the drum, so the following tables show target times to reach 1st and 2nd crack. Keep in mind that all coffees and grills vary, so you won’t land on these numbers exactly, but you should be able to get within a minute.

The suggested temperatures in the tables require a bit of explanation. These suggested temperatures are the readings on the thermostat that you will be using in your grill, not the temperature reading inside the drum or the bean temperature. If the probe on your thermometer happens to be located directly above the flame, the temperature reading will be higher than if it is located above the drum and not touching any flame. In other words, the thermometer tells us a relative temperature – not the direct temperature of the beans, but rather a temperature that is some amount higher than the bean temperature. With that in mind, understand that the first roasts in a new setup are essentially calibration roasts, as we learn what temperature our thermometer should read in order to finish at the target time. You will not ruin any coffee, but it won’t be perfect either.

Green weight and finished weight also might need a bit of explanation. During the roast, water in the bean evaporates, which causes the bean to weigh less after it is roasted than when it began. To get the desired amount of coffee, “finished weight”, you will need to measure out the green coffee in the amount listed in the “green weight” column.

The main idea is that you get the best tasting coffee by roasting it so that it finishes right at the expected time, (that is, the time in the “target 2nd crack” column of the table). If your roast at the suggested temperature finishes after the target 2nd crack time, then crank up the temperature the next time. Or, conversely, if your roast at the suggested temperature finishes before the target 2nd crack time, the turn down the heat a bit the next time.

Roast Profiles for the 2LB RK Drum

Finished Weight Green Weight Percent Loaded Suggested
Temperature(1,3)
Target
1st
Crack(2,3)
Target
2nd
Crack(2,3)
1/2 LB
9.6 oz
25%
470°F (243°C)
6 minutes
10 minutes
1 LB
1 LB 3.2 oz
50%
500°F to 525°F (260°C to 274°C)
9 minutes
12 minutes
1 1/2 LB
1 LB 12.8 oz
75%
525°F to 550°F (274°C to 289°C)
14 minutes
16 minutes
2 LBS
2 LB 6.4 oz
100%
550°F to 600°F (289°C to 316°C)
16 minutes
18 minutes
(1) – The temperatures listed in the table are suggested starting temperatures for targeting the times for 1st and 2nd crack.
(2) – Times in the columns labeled, “1st Crack” and “2nd Crack” are the optimal target times for 1st and 2nd crack to occur, respectively.
(3) – Coffee will taste best when 1st and 2nd crack occur at the target number of minutes into the roast. If 1st and 2nd crack happen after the target times, then increase the temperature on the next roast. If 1st and 2nd crack happen before the the target times, then decrease the temperature on the next roast.

Roast Profiles for the 4LB RK Drum

Finished Weight Green Weight Percent Loaded Suggested
Temperature(1,3)
Target
1st
Crack(2,3)
Target
2nd
Crack(2,3)
1 LB
1 LB 3.2 OZ
25%
470°F (243°C)
8 minutes
12 minutes
2 LBS
2 LBS 6.4 OZ
50%
500°F to 525°F (260°C to 274°C)
11 minutes
14 minutes
3 LBS
3 LBS 9.6 OZ
75%
525°F to 550°F (274°C to 289°C)
16 minutes
18 minutes
4 LBS
4 LBS 12.8 OZ
100%
550°F to 600°F (289°C to 316°C)
18 minutes
20-21 minutes
(1) – The temperatures listed in the table are suggested starting temperatures for targeting the times for 1st and 2nd crack.
(2) – Times in the columns labeled, “1st Crack” and “2nd Crack” are the optimal target times for 1st and 2nd crack to occur, respectively.
(3) – Coffee will taste best when 1st and 2nd crack occur at the target number of minutes into the roast. If 1st and 2nd crack happen after the target times, then increase the temperature on the next roast. If 1st and 2nd crack happen before the the target times, then decrease the temperature on the next roast.

Roast Profiles for the 6LB RK Drum

Finished Weight Green Weight Percent Loaded Suggested
Temperature(1,3)
Target
1st
Crack(2,3)
Target
2nd
Crack(2,3)
1 LB
1 LB 3.2 OZ
16.6%
450°F to 470°F (232°C to 243°C)
8 minutes
10 minutes
2 LBS
2 LBS 6.4 OZ
33.3%
470°F to 500°F (243°C to 260°C)
12 minutes
14 minutes
3 LBS
3 LBS 9.6 OZ
50%
500°F to 525°F (260°C to 274°C)
14 minutes
16 minutes
4 LBS
4 LBS 12.8 OZ
66.6%
525°F to 550°F (274°C to 289°C)
16 minutes
18 minutes
5 LBS
6 LBS
83.3%
550°F to 575°F (289°C to 302°C)
18 minutes
19 minutes
6 LBS
7 LBS 3.2 OZ
100%
575°F to 625°F (302°C to 329°C)
19 minutes
21 minutes
(1) – The temperatures listed in the table are suggested starting temperatures for targeting the times for 1st and 2nd crack.
(2) – Times in the columns labeled, “1st Crack” and “2nd Crack” are the optimal target times for 1st and 2nd crack to occur, respectively.
(3) – Coffee will taste best when 1st and 2nd crack occur at the target number of minutes into the roast. If 1st and 2nd crack happen after the target times, then increase the temperature on the next roast. If 1st and 2nd crack happen before the the target times, then decrease the temperature on the next roast.

Roast Profiles for the 8LB RK Drum

Finished Weight Green Weight Percent Loaded Suggested
Temperature(1,3)
Target
1st
Crack(2,3)
Target
2nd
Crack(2,3)
1 LB
1 LB 3.2 OZ
12.5%
450°F to 470°F (232°C to 243°C)
8 minutes
10 minutes
2 LBS
2 LBS 6.4 OZ
25%
470°F to 480°F (243°C to 249°C)
10 minutes
12 minutes
3 LBS
3 LBS 9.6 OZ
37.5%
490°F to 500°F (254°C to 260°C)
12 minutes
14 minutes
4 LBS
4 LBS 12.8 OZ
50%
500°F to 525°F (260°C to 274°C)
14 minutes
15.5 minutes
5 LBS
6 LBS
62.5%
525°F to 535°F (274°C to 279°C)
16 minutes
17.5 minutes
6 LBS
7 LBS 3.2 OZ
75%
535°F to 565°F (279°C to 296°C)
17 minutes
19 minutes
7 LBS
8 LBS 6.4 OZ
87.5%
565°F to 585°F (296°C to 307°C)
19 minutes
20.5 minutes
8 LBS
9 LBS 9.6 OZ
100%
600°F to 625°F (316°C to 329°C)
19 minutes
21 minutes
(1) – The temperatures listed in the table are suggested starting temperatures for targeting the times for 1st and 2nd crack.
(2) – Times in the columns labeled, “1st Crack” and “2nd Crack” are the optimal target times for 1st and 2nd crack to occur, respectively.
(3) – Coffee will taste best when 1st and 2nd crack occur at the target number of minutes into the roast. If 1st and 2nd crack happen after the target times, then increase the temperature on the next roast. If 1st and 2nd crack happen before the the target times, then decrease the temperature on the next roast.

Roast Profiles for the 12LB RK Drum

Finished Weight Green Weight Percent Loaded Suggested
Temperature(1,3)
Target
1st
Crack(2,3)
Target
2nd
Crack(2,3)
1 LB
1 LB 3.2 OZ
8.3%
450°F to 470°F (232°C to 243°C)
8 minutes
10 minutes
2 LBS
2 LBS 6.4 OZ
17%
470°F to 480°F (243°C to 249°C)
9 minutes
11 minutes
3 LBS
3 LBS 9.6 OZ
25%
490°F to 500°F (254°C to 260°C)
9 minutes
11 minutes
4 LBS
4 LBS 12.8 OZ
33%
500°F to 525°F (260°C to 274°C)
10 minutes
12 minutes
5 LBS
6 LBS
42%
525°F to 535°F (274°C to 279°C)
12 minutes
14 minutes
6 LBS
7 LBS 3.2 OZ
50%
535°F to 565°F (279°C to 296°C)
12 minutes
14 minutes
7 LBS
8 LBS 6.4 OZ
58.3%
565°F to 585°F (296°C to 307°C)
16 minutes
17.5 minutes
8 LBS
9 LBS 9.6 OZ
66%
600°F to 625°F (316°C to 329°C)
16 minutes
17.5 minutes
9 LBS
10 LBS 12.8 OZ
75%
625°F to 650°F (329°C to 343°C)
17 minutes
19 minutes
10 LBS
12 LBS
83%
625°F to 650°F (329°C to 343°C)
17 minutes
19 minutes
11 LBS
13 LBS 3.2 OZ
92%
650°F to 675°F (343°C to 358°C)
19 minutes
21 minutes
12 LBS
14 LBS 6.4 OZ
100%
650°F to 675°F (343°C to 358°C)
19 minutes
21 minutes
(1) – The temperatures listed in the table are suggested starting temperatures for targeting the times for 1st and 2nd crack.
(2) – Times in the columns labeled, “1st Crack” and “2nd Crack” are the optimal target times for 1st and 2nd crack to occur, respectively.
(3) – Coffee will taste best when 1st and 2nd crack occur at the target number of minutes into the roast. If 1st and 2nd crack happen after the target times, then increase the temperature on the next roast. If 1st and 2nd crack happen before the the target times, then decrease the temperature on the next roast.