Roasting Profiles for RK Drums
Steps to Successful Roasting with the Profile Charts
How to perform your first roast (Calibration Roast)
- Select the specific chart for your drum below.
- Start your first calibration roast with the 1LB option (row). If things don’t go well, you won’t be risking much coffee.
- Weigh out the amount of coffee for 1LB finished (1LB 3.2 oz. green).
- Choose a temperature from the suggested temperature (470F is the middle-ground temperature for 1LB).
- Preheat your drum to 470F.
- Remove the drum fill with coffee.
- Replace the Drum in the roaster.
- Start the roaster and simultaneously start your timer on your phone or stopwatch.
- Hold 470F no matter what. If it creeps up, lower the gas, or lift the grill lid. If it creeps down, add gas…
- You’re hoping for a 1st crack at 8 mins, and a 2nd crack at 10 mins. This is the goal. If crack arrives earlier than 8 mins, then you’re too hot, and future roasts should be completed at a lower temp. If you hit 8 mins without a crack, then you’re too cold. Add heat right away to compensate (20 degrees is a good number).
- Pull the coffee at 10-in-10, of second crack. (10 cracks in 10 seconds) and cool as quickly as possible.
- Make note, if your 1st roast arrived at first crack too fast (faster than 8 mins) or not fast enough.
- Adjust your temperature up or down in order to drive the cracks on time. (8 and 10 mins in this case per the 1LB row of your chart.) Note that we have people roasting at 750F and others at 350F due to what your thermometer happens to be feeling at the location it is installed. This isn’t a problem, as it’s merely an internal reference temperature. You won’t end up, necessarily, with the temperatures in our charts, but something slightly, or greatly different. We simply suggest these temperatures as starting points since those temperatures works for more people than not. You will need to find what temperature works in your unique roaster. Please call or email if you would like assistance with this part. We coach this part daily. For more on this subject see the following resources:
Article on Thermometer Relativity
Video on Thermometer Relativity
Roast #2 and Subsequent Roasts.
- If your first roast was too hot and fast, remove heat for the second roast or if your first roast was too cold and slow, add heat. 20-30 degree increments are a good guess for each minute off of your target. Adjust more or less accordingly.
- Select the new temperature, and hold this temperature to see if this new temperature delivers the cracks on time.
- Repeat the above 2 steps, until you have the coffee cracking on time, per the charts, by adjusting your temp up or down. Temperature up to speed up the roast, temp down to slow down. You should be able to get accuracy and predictability to within 15 seconds within 3 or 4 ten minute roasts attempts. Once you have the temperature that drives your cracks on time, write this number down. This is YOUR temperature in YOUR roaster for that specific coffee weight.
- Repeat this process for a few other strategic volumes. For example, an 8LB drum would commonly use a 1LB, 4LB and 8LB test roasts. From those numbers you can interpolate other roasts sizes if needed, but these strategic sizes may be all you ever really need.
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.
(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.
(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.
(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.
(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.
(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.