A couple of years ago I took my Saeco Via Venezia and added a PID to it. A PID is used in many machine (like your oven!) to control temperature and I wanted to use it to better regulate my espresso machine.
The problem with most cheap espresso machines is that the temperature is regulated by a temperature limited fuse… when the grouphead (where the water heats up and pressurizes) gets too hot, it turns off the heater. This is a great idea, but most of the time they don’t do the job very well. This is why on most commercial espresso machines you have to have to “magic touch” and know exactly when the machine is at the right heat to a perfect cup.
With the PID installed, I can simply set the it to 200° and walk away. Once the machine reaches the set temperature it maintains it, waiting for me to make my cup. This has VASTLY improved the quality of espresso coming out of the machine and was one of the best coffee related things I’ve done in a while. Other good tips are to de-pressurize your portafilter so that you can control the density of the espresso better (most cheap machines come with an auto-tamping system and the portafilter is pressurized… this makes it easier to make a good cup of espresso with crema, but having the manual control let’s you change the flavors you want to express in each extraction).
In order to do this hack, you’ll need the following supplies:
- 1/16 DIN PID Temperature Controller (SSR control output) ($45.50)
- 40 amp SSR (solid state relay) ($19.00)
- K Type Thermocouple ($3.95)
which brings the total to $68.45. The build is quite easy and shouldn’t take too long to do… the hardest part is tracing the wires and figuring out what is what. Unfortunately, I did this hack a while ago and these are the only pictures I found, but it should be more than enough to replicate the project! Good luck!