Java Master 2002 Coffee Roaster

Java Master 2002 Coffee Roaster

Owner/Loaner	Theo Tetzlaff
Serial Number	2736
Make/Model	Java Master 2002
Arrival Date	June 2022
Usability	yes
Contact	Theo Tetzlaff
Where	General Area
Authorization Needed	yes
Hackable	no
Estimated Value	$7,500
Host Area	General Area

Description

This is a Java Master 2002 fluid bed coffee roaster, capable of roasting up to 3.5 lbs green beans per batch.

Roast Profile

Roasting Profiles refer broadly to important parameters and conditions of the roasting process. The roasting process is a process of caramelization and carbonization called a Maillard Reaction. Some important roast parameters include:

• Temperature at beginning of roast
• Temperature at ending of roast
• Total Duration of roast
• Rate of Rise in temperature over total duration and specific periods of roast
• ‘Development’ of roast at specific temperatures during specific sequences of the roast
• Degree of ‘crack’ achieved in the bean (i.e. First, Second)
• Color achieved
• Speed of air cooling of beans (this part is a significant contributor to ‘sweetness’ in the cup)

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 is determined by two separate controlled parameters: hot air temperature and bean temperature. Hot air temperature is set on the left PID controller. It should be adjusted based on the bean weight to be roasted and the desired speed of roast, and is the temperature of the air entering the roast chamber. More beans require more heat to roast at the same speed. Target bean temperature is set on the right PID controller, and corresponds to the temperature of the air exiting the chamber. When this temperature is reached, the machine begins its cool down cycle. Note that this number is a significant underestimate of the actual bean temperature, but it provides an easily measured parameter for when to end the roast. This temperature can also be adjusted while the roast is in progress to prolong or end the roast earlier, but note that the PID controller takes several seconds to recognize the change.

Suggested roasting parameters:

Hot air temperature range is 530-575 F on the controller. For 1-2 lbs, it should be set close to 530 F. For 2-3.5 lbs, it should be set between 540-560.

Target bean temperature can be set between 370-445 F. This parameter determines the darkness of the roast. Suggested starting points for experimentation:

• City (first crack complete) - 375 F.
• City+ (significant development beyond first crack) - 380 F to 390 F.
• Full City (right before second crack) - 400 F (may be higher.)
• Full City+ (some but not all beans have gone through second crack - 415 F.
• Second crack complete - 420 F.
• French roast - 425 F?

Additional efforts are being made for us to be able to ‘log’ roasts as temperature over time graphs, in order to compare roast profiles for individual beans and measure outcomes.

Operation Checklist

• Get stuff ready:
  • Get hopper, funnel, bags from Kitchen
  • Weigh beans (Small Metals has a scale)
• Hook up water hose and turn on
• Plug in
• Turn Power on
• Turn Heat on
• Check (and, if necessary, empty) chaff collector
• Set air and bean temperatures
• Put hopper in place over the blower vents
• Pour in beans
• Make certain the top cap is in place
• Press the Run button
• Hot air heats up beans, eventually beans reach set Bean temperature
• Machine turns off heat, cooling water starts, machine continues to blow air to cool down beans
• Wait for bean temp to drop below 370 F, at which point yellow Reset lamp lights
• The operator can dump the beans now, or continue to cool the beans in the chamber. To dump:
  • Press the Stop button.
  • Pull the handle to dispense beans into hopper.
  • Let the air vents under the hopper cool the beans.
• Bag the beans
• Turn off Heat and Power switches
• Disconnect power
• Turn off water and disconnect hose
• Put hose back nearly
• Put machine back
• Return hopper, funnel, and supplies to Kitchen

Safety

• Never run a roast unattended! (Please!)
• Do not roast anything other than green coffee beans.
• Roasting beans that already have been roasted is a fire hazard.
• Minimum and maximum load are 1 - 3.5 lbs green beans.
• Make sure the chaff collector has adequate space. Empty it regularly.
• Do not operate without the water connected, the valve on, and the hose not kinked.
• Beans above 300 F, without cooling air flow or not in motion in the roaster, can catch fire. Stopping the roast is therefore bad. A power outage during a roast is also bad. The roast should be allowed to complete.
• The roast can safely be stopped once bean temperature reaches the target, the cooling cycle engages, and the beans drop to 370 F. When this happens, the yellow Reset light will illuminate. Beans can be allowed to cool in the chamber, or the roast stopped with the Stop button and the beans then immediately dumped into the cooling hopper by using the lever. Fans on the tabletop in front of the roaster will blow cooling air over the roast beans. Beans will cool in the hopper via cooling fans within about 3-4 minutes after roast.
• A manual valve is located on the left side of the machine, which will trigger a water sprayer to flood the chamber. Use this only in case of a bean fire in the chamber.
• Should temperature rise in the chamber uncontrollably, the system will automatically engage the water sprayer. Disable, when any fire is put out, with the Reset button.
• No roast should take more than 15 minutes. A timer will halt a roast after 15 minutes. Larger quantities of beans roasted darker may need higher air temperature to ensure the target is reached before 15 minutes.
• The front external parts of the roaster may get very hot in operation, especially continuous operation. Do not touch hot metal. Please.
• Do not use the roaster for high volume commercial production. This is expensive and on loan. Let’s not PS1 it, okay?

List of Currently Authorized Users

Qualified Member	Trained By	Date
Theo Tetzlaff	Owner/Why would I do this to myself?
Ryan Pierce	Danger Committee/Manager/Trainer/BAMF
Carl Karsten	Ryan Pierce	11/9/22
Ron Olson	Ryan Pierce	11/16/22
Dan Wells	Ryan Pierce	11/16/22
James Lamken	Ryan Pierce	11/16/22
Claire Fiorino	Theo Tetzlaff	11/20/22
Ian Sampson	Theo Tetzlaff	11/20/22
Joseph Staffa	Ryan Pierce	12/14/22
Andrew Wingate	Ryan Pierce	1/3/23
Elizabeth Koprucki	Ryan Pierce	1/4/23
William Shehan	Ryan Pierce	1/5/23
Laura Sparks	Ryan Pierce	1/5/23
Patrick Mahon	Theo Tetzlaff	1/18/23

Green Coffee Bean Suppliers

• JavaMaster - Sells in 3.5, 10, and 40 lbs quantities.
• Sweet Maria’s - Sells in 1, 2, 5, 10, and 20 lbs quantities.
• Coffee Shrub - Larger volume sister company to Sweet Maria’s.
• Isabella Imports - Sells in 1 lb increments. A Galena, IL based company that has some interesting selections.
• Dean’s Beans - Some good selections available.
• Amazon, gourmet foods section - yes… Amazon.
• Coffee & Tea Exchange - Local Chicago store on Broadway that will sell green beans.

Please note, of these, I really can’t stress enough how generally superior and much more transparent + informative I find Sweet Maria’s compared to everywhere else. -Theo

Sweet Maria’s is great for the beginning roaster because they provide highly detailed cupping notes, suggestions on what level of roast to use, and their opinion on whether something would make good espresso. But the quality of the beans is a function of the grower, not the importer, and a big part of this adventure is discovery and experimentation. So I’d suggest eventually branching out and trying other importers once you have some experience under your belt. -Ryan

Maintenance

Task	Date	Done by	Notes
Clean two exhaust thermocouples	10/26/23	Ryan
Clean glass chamber	12/21/22	Ryan
	10/24/22	Theo and Ryan	Spot cleaning only
Clean upper duct	12/21/22	Ryan	Spot cleaning only
	10/24/22	Theo and Ryan	Spot cleaning only
Vacuum clean air intake filter	10/26/22	Ryan
Clean lower dump valve	12/21/22	Ryan	Spot cleaning only
	10/24/22	Theo and Ryan	Spot cleaning only
Replace upper chamber gasket	12/21/22	Ryan
Clean hot air thermocouple	10/26/22	Ryan

Nota Bene:

• We have replacement gaskets and seals now for the roast chamber + venting tubes, etc.
• Chaff collector should be checked regularly, depending on frequency and scale of roasting. Not a big deal, but consider checking chaff collector before a new roasting session and/or after roasting several times in succession with beans that give off more chaff [e.g., ‘washed’ beans].

Technical Details

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.