Managing a coffee roasting machine's thermal energy to insure every roast batch begins with the same thermal state is key to achieving consistency and expected results. Roast operators employ a Between Batch Protocol (BBP) to achieve this. Artisan supports Between Batch Protocols in multiple ways. This article explores the metrics Artisan captures to help the roast operator observe and manage their BBP.
Background
There is much written and taught about creating and applying an effective BBP. We won't examine those theories here. Artisan supports them all. Artisan can record the BBP before, after or separately from the batch roast. It can record and graph a BBP that rises to a temperature higher than the CHARGE temperature then falls before CHARGE or a BBP where the temperature drops and then rises to the CHARGE temperature. More details can be found in Supporting Between Batch Protocols.
In addition to recording and graphing temperatures throughout the roast, Artisan captures information relevant to characterizing the BBP.
The metrics tracked by Artisan make two assumptions. First, that the BBP protocol and roast batch are a single recording where the BBP is recorded starting before the CHARGE event. Think of the BBP as the lead-in to the roast recording. The recording should start as soon as possible after the previous batch so as much of the BBP as possible is captured. The second assumption is that the BBP temperature falls to a bottom temperature and is then increased to the CHARGE temperature. We believe this is the most often used approach.
A BBP with rising temperatures that later fall to the CHARGE temperature is a valid approach. If that works for you keep doing it. Artisan will accurately record your BBP, however some of the metrics captured by Artisan assume there is a bottoming temperature.
Here are two roasts shown back to back. After the first roast ends there is a few seconds gap before the following roast recording starts.
Note that this graph was created by manually stitching these two roasts together to illustrate the BBP. This BBP works well with this roaster. Your BBP may have a different shape with different times and temperatures.
Under the covers
During a roast session Artisan keeps track of several data points to use in calculating the BBP metrics. These data points come from the previous roast and the current roast. The data points are assembled into a set of metrics that can be displayed in the Summary Statistics box. They are also available in the Ranking Report when saved in Excel or CSV format.
BBP starts at DROP and continues until the next CHARGE. For this reason it is important to start the next recording as soon as possible after DROP. Below you will find a procedure to do this efficiently.
For capturing BBP statistics, Artisan assumes that the START of a roast recording happens no later than 60 seconds after the previous DROP. If START happens after 60 seconds Artisan assumes that BBP began at START instead of the previous DROP. Regardless where it began, to be considered valid a BBP must be longer than 90 seconds.
If you normally record the roast cooling phase that follows DROP you may need to adapt your process if you wish to capture the BBP. This is a choice to make, there is no right or wrong answer.
Reported BBP Information
Artisan reports the following BBP statistics:
- BBP total time
- BBP Beginning (DROP or START)
- Time from beginning of BBP to bottom temperature
- Bottom temperature
- Time from bottom temperature to CHARGE
- CHARGE temperature
The Ranking report (menu File>> Report>> Ranking) when saved in Excel or CSV format includes the above information plus:
- BBP Begin to Bottom RoR (deg/min)
- BBP Bottom to CHARGE RoR (deg/min)
Displaying the BBP metrics
The Summary Statistics box (menu Config>> Statistics>> Stats Summary tab) allows displaying BBP statistics in compact and full formats. The image below shows the appearance of the various Summary Statistics.
How to efficiently capture BBP
1. Enable Config>> Sampling>> Keep ON
When OFF is pressed to end a roast Artisan will transition back to the ON state without any user intervention.
2. Add an alarm to automatically START after ON. Otherwise manually click START quickly.
Note: With this alarm and Keep ON enabled Artisan will automatically press START each time OFF is clicked and a new roast recording will begin. To exit this loop after the last batch of the day click OFF a second time in the first few seconds after Artisan STARTs.
3. [Optional] Enable Config>> Sampling>> Open Completed Roast in Viewer.
This allows you to make edits to the just completed roast. For more information see "Completed Roast in ArtisanViewer" in Working Together – Artisan, ArtisanViewer and artisan.plus.
Conclusion
Artisan allows wide flexibility to record, monitor, characterize and analyze any Between Batch Protocol. Dialing in the BBP on each roasting machine will improve batch to batch consistency from the first batch of the day through to the last.
If you have any questions or comments please start a Discussion item.
Happy roasting!
Dave