Java Master 2002 Coffee Roaster: Difference between revisions
From Pumping Station One
No edit summary |
. |
||
| Line 33: | Line 33: | ||
In general, coffee sugars are made accessible by roasting, but the caramelization process also reduces perceptual sweetness over roast time at a similar degree of roast. Additionally caffeine content lowers over time with off-gassing from longer roasts. Acidity also tends to lessen over time past City+ and into Full City/Second Crack, until carbonic acidity eventually raises in the darkest roasts. Roasters aim for a consistent rate of rise over time, just as with making caramel, so that the caramelization process does not stop and start haltingly, which will reduce perceptual sweetness as well and lead to uneven bean development. | In general, coffee sugars are made accessible by roasting, but the caramelization process also reduces perceptual sweetness over roast time at a similar degree of roast. Additionally caffeine content lowers over time with off-gassing from longer roasts. Acidity also tends to lessen over time past City+ and into Full City/Second Crack, until carbonic acidity eventually raises in the darkest roasts. Roasters aim for a consistent rate of rise over time, just as with making caramel, so that the caramelization process does not stop and start haltingly, which will reduce perceptual sweetness as well and lead to uneven bean development. | ||
'''Roasting on the Java Master''' | '''Roasting on the Java Master''' | ||
| Line 173: | Line 172: | ||
|David Earl | |David Earl | ||
|Theo Tetzlaff | |Theo Tetzlaff | ||
Riley Pierce (refresher 9/8/23) | |Riley Pierce (refresher 9/8/23) | ||
|4/16/23 | |4/16/23 | ||
|- | |- | ||
| Line 407: | Line 406: | ||
The roaster uses a Watlow PID controller (on the left) to control air temperature. It outputs a process value (4-20 mA), which an Avatar Instruments power controller uses to change the power to the heater via SCR phase dimming. The Avatar supports 240 V but the heater itself only can handle 208 V. This machine was designed to operate on 208 V but JavaMaster confirms it can operate on 240 V with an adjustment. Originally, JavaMaster suggested we limit the PID to 70% max output power. But that resulted in unexplained oscillations in temperature typically +/- 30 F. The Avatar includes an optional feature to limit output voltage via the V-LIM trim pot. This was adjusted so 100% on the PID corresponds to 208 V as measured by a true RMS voltmeter. If the machine is ever operated at 208 V again, it will require re-adjustment of this trim pot. | The roaster uses a Watlow PID controller (on the left) to control air temperature. It outputs a process value (4-20 mA), which an Avatar Instruments power controller uses to change the power to the heater via SCR phase dimming. The Avatar supports 240 V but the heater itself only can handle 208 V. This machine was designed to operate on 208 V but JavaMaster confirms it can operate on 240 V with an adjustment. Originally, JavaMaster suggested we limit the PID to 70% max output power. But that resulted in unexplained oscillations in temperature typically +/- 30 F. The Avatar includes an optional feature to limit output voltage via the V-LIM trim pot. This was adjusted so 100% on the PID corresponds to 208 V as measured by a true RMS voltmeter. If the machine is ever operated at 208 V again, it will require re-adjustment of this trim pot. | ||
It seems the main fuse has fallen out of the fuse block in the past. Wmare looking for a better way to secure it. | |||
If a roast is stopped before cooldown completes, it is possible that the PLC will get confused about roast state, and the next roast will not shut itself down. If a roast is ever aborted before cooldown, SHUT DOWN THE MACHINE before powering up and running another roast. | |||
[[Category:Loaned Equipment]] | [[Category:Loaned Equipment]] | ||
