It’s easy to say “PID controllers are audiophile tech for coffee machines”, but the most basic construction for temperature control is a thermostat, and that ha

It’s easy to say “PID controllers are audiophile tech for coffee machines”, but the most basic construction for temperature control is a thermostat, and that has been good enough for Italian coffee machines for a very long time. A PID controller is positively space age technology compared to a bi-metal thermostat. Where PID controllers shine is in well built but small capacity machines. A Silvia has a tiny 300mL boiler. If you’re pulling a double shot (60mL), you’re losing 20% of the heat just from pumping fresh water into the boiler. Add a PID controller to the mix, the static losses are accounted for by the integral controller, and it will instantly ramp up the heat when you pull a shot via the derivative and proportional action. This would keep the temperature significantly more consistent during a 30 second shot. A PID controller in this instance is transformative in turning a comparatively cheap machine into a very capable piece of kit. In a larger machine with a 1L boiler pulling a shot barely causes a ripple in temperature because of the larger boiler capacity and additional heat inertia. They might benefit from a PID controller but it’s difficult to justify over the simplicity of a thermostat, and coffee machines have been around longer than electronics have been cheap.