PID'd Popper Roasting
F e l i x  D i a l
f e l i x d i a l at cox dot net

I no longer use the control station to roast coffee. I bought a PID and use it to do the temperature ramping. Figure 1 below is a photo of my roasting setup. I now roast in my garage. The chaff collector was inspired by a photo I saw at sweetmarias (http://www.sweetmarias.com/hearthI-Roast-chaffcollect.html). My next project is to mount the heat control box, SSR/heatsink and the PID-Project box on a plank of wood. It's all a bit untidy sitting there on the table like it is, but it's all very functional. Perhaps when I have more time ...


Figure 1

Here's a close-up of the controller. Note the On-Off switch (Radio Shack Item 275-693) towards the rear of the project box (Radio Shack Item 270-1805).


Figure 2
The photo photo below shows the insides of the project box that houses the PID.


Figure 3

Here's a close-up of the SSR. It's hard to see, but the SSR is mounted on a heatsink.


Figure 4
The heat circuit plugs into the SSR-PID circuit and the fan circuit plugs into the variac. So now the only dial I have to twiddle is the Variac dial that controls fan speed. The figure below shows the box that the heat circuit from the popper plugs into. The switch in the lower left toggles between the PID/SSR circuit and AC. This switch controls the receptacle right next to it labeled "HEAT". If I ever want to override the PID controller, I just toggle the switch to the AC position and the heater on the popper takes uninterrupted AC. Bob Yellin sent me a wiring diagram for this setup.


Figure 5

I purchased the PID and SSR from TTIglobal (www.ttiglobal.com). From reading alt.coffee, a good number of homeroasters and espresso-philes who've modified their coffee roasters and espresso machines purchased their PIDs from TTIglobal. If you do call them, ask for either Dwight or Jason. Dwight's name gets dropped as the rep to contact, but Jason was the one who helped me with my order. Also, the big plus with ordering your PID from TTIglobal is that if you ask, they'll pre-program the PID with the following roasting profile: (260°F, 2 minute ramp) (290°F, 3 minute ramp) (380°F, 3 minute ramp) (410°F, 2 minute ramp) (460°F, 5 minute ramp).  Soak times are set for zero duration. My invoice has this labeled as "COFFEE ROASTER SPECIAL PROGRAM".

The following were purchased from TTIglobal:

A few links to explain all of this roaster PID non-sense: Other PID setups:


last modified: 07 September 2004
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