What Are PIDs? Overview and History
This photo shows a digital PID controller on a Quick Mill QM67 Evo.
Many espresso machines have a feature called a PID or PID controller, a very common question people have when they are looking for espresso machines is, "What is a PID and why would I want to have an espresso machine with this feature?".
PID stands for Proportional Integral Derivative. Fancy name, but it's pretty much a temperature controller that uses an advanced algorithm to maintain the temperature of the machine at a programmed or set temperature.
There is some disagreement relating to when the first espresso machine had a PID. The first machine to have a PID was Stein-O-Matic machine produced for a limited time in the 1980s, but the purpose of the PID on this machine was not to maintain temperature stability. So a lot of people credit an owner of a tofu manufacturing business, Andy Schector, as being the first person to use a PID on an espresso machine with the express purpose of maintaining temperature stability. He was already using PIDs in his tofu business, so he knew a lot about them and decided to add one to his Rancilio Silvia espresso machine. He did this in 2001. Shortly afterwards, La Marzocco started selling one of their machine models with PID upgrade option, making it the first brand to have PIDs on their machines. Other brands quickly followed suit and now most prosumer and commercial espresso machine brands have at least some models with PID controllers.
How important is PID on espresso machine?
Most PID controllers allows users to increase or decrease the temperature, which can have a big impact on the flavor of espresso being brewed. Every coffee bean has a different ideal brew temperature, so having a PID temperature adjuster for brewing espresso has the biggest impact, but PIDs can also be used to adjust the temperature of the steam boiler. Increasing or decreasing the steam boiler temperature will allow the user to fine tune the steaming performance of the machine. Some people prefer a hotter and drier steam, while others prefer the steam to be a bit cooler. A higher temperature means more steam pressure and a lower temperature means less steam pressure. There are certainly pros to having a PID on your coffee machine and there really aren't any cons - except that machines without PIDs are usually lower priced, than machines with PIDs.
Temperature Stability of PID Espresso Machines vs Mechanical Temperature Controlled Machines
PID Temperature Stability
This graph represents the temperature fluctuations of an espresso machine that has a PID. The ups and downs are related to the PID pulsing the boiler on and off to maintain the temperature.
Mechanical Temperature Controller Stability
This graph represents the temperature fluctuation of espresso machines that have thermostat or pressurestat temperature controllers. Note the higher peaks and valleys when compared to the PID graph above. These peaks and valleys represent a higher range in temperature above and below the set temperature.
Single Boiler Espresso Machines with PID
On a single boiler home espresso machine having a PID is ideal for achieving the ideal brew temperature for the specific bean type you are using. PIDs on single boiler machines provide a stable temperature for brewing, but can also be used to help determine when the machine is ready for steaming. Our top single boiler machines that have PIDs include the following: Bezzera Unica PID, Quick Mill Alexia Evo, and the ECM Germany Classika PID.
Heat Exchanger Espresso Machines with PID
PIDs on heat exchange espresso machines control the temperature of the steam boiler, but due to the way a heat exchanger is designed for brewing, you cannot directly control brew temperature through a PID temperature controller on an hx machine. However, raising or lowering the steam temperature does indirectly raise and lower the brew temperature, so you do get some benefit from being able to do that. Having the ability to raise and lower steam temperature is also beneficial if you want to control steam pressure.
Top HX Espresso Machines with PID
Izzo Vivi 3, Rocket Mozzafiato Type V, Bezzera Mitica PID, Rocket Giotto Evoluzione R with PID, and the Bezzera Magica with PID.
Double Boiler Espresso Machine with PID
Most double boiler espresso machines have PIDs. If you want to get the most benefit out of having a PID, a double boiler machine is the way to go. With a double boiler machine, you have precise control over both brew and steam temperature. PIDs on a double boiler machine provide an adjustable stable temperature for brewing as well as steaming.
Top Dual Boilers with PID
Our top selling double boiler machines that have PIDs include: Quick Mill Silvano Evo, La Spaziales, Quick Mill QM67, Quick Mill Vetrano, Izzo Alex Duetto IV Plus, and the Rocket R58. If you want a top of the line, higher end machine, then the Rocket R Nine One, ACS Vesuvius and the Slayer one group are great double boiler machines with outstanding temperature control and stability.