PID

  • What's a PID?

    You may have seen that certain espresso machines include what's called a "PID," or "PID controller" more accurately. This week, we're going to talk about what a PID controller is, and why it's worth the extra cost!

     

    The Basics

    If you've been following along with us, you probably know that temperature is extremely important to brewing coffee. While different brew methods and roasts demand different temps, stability is key. PID controllers help ensure that stability. Machines without these devices often use a simple thermostat that isn't as accurate as a PID controller. By comparison, a machine with PID control monitors itself to ensure temperature stability and control.

    PID stands for Proportional-Integral-Derivative. Quite a mouthful! On a basic level, a PID controller uses the PID algorithm to determine the best way to control whatever process it's used for. PID controllers are used in a wide range of industrial applications, in our case, it controls the temperature in your espresso machine!

    A traditional thermostat has a tendency to hit a desired temp, then turn off the heating element as the temp rises above its target. Then it'll kick back on as the temperature falls below the target. This results in uneven temperatures that can result in inconsistent shot quality in an espresso machine. There are ways to mitigate this with many machines, but it often means learning how to ride the temperature wave with your specific machine. This may require timing the heat-up time precisely or running water through the group head before pulling a shot.

    PID controllers use the PID algorithm to keep your machine at the proper brew temperature. This also means the you can directly control the temperature of the machine. While not true in every case, PID controllers are usually visible on the machine. They also usually feature control buttons to increase or decrease the brewing temperature. While this won't matter for most, for some home baristas, experimenting with different roasts and temps is key!

    So You Want a PID Controller?

    It's possible to install a PID controller into most home espresso machines. The process however, can be daunting. Performing an after-market install of these devices is essentially rewiring the machine. You'll have to find the thermostat, disconnect it, and install the PID controller. This will require a pretty strong understanding of how these devices work, and competency in basic electrical work. You'll also need to understand how to program the PID controller , as these are devices used for a wide range of applications. Some vendors offer kits for specific espresso machines that will make this process easier. In any case, installation of a PID controller will definitely void your warranty.

    But there is hope! If you're in the market for a new machine, many now come with PID controllers installed. These devices used to be used primarily on commercial hardware, but have entered the home market. While you might pay a little extra for a machine with one of these devices, it'll come under warranty and save you digging around the guts of your machine. Once you have a PID controller, you'll be able to eliminate temperature as one of the variables in dialing in your shots.

    It's important to note, some PID controllers are clearly visible boxes attached to the machine. The PID installed in the photo above is an example of this. Other machines have external PIDs that are attached via a cable. Further, some PID controllers are internal and show up as a small screen on the machine, like the Ascaso Dream above. Finally, some machines have internal PIDs that do not have an interface. In these cases, you won't be able to control the temp easily, but the PID controller is still keeping it stable at a set level.

    We hope this helps de-mystify these devices!

  • Morning Maintenance: Programming a PID

    Time and temperature. If you break down the essentials of a good cup of coffee/shot of espresso you will arrive at two variables: time and temperature.Silvia PID

    It doesn't matter how fresh your coffee is or how expertly roasted it was. If your brewing time and temperature are not correct, you end up with something you don't want to drink. So what's the best way to control those two variables? With a PID of course.

    Especially on a single boiler machine, where the boiler temperature will fluctuate between brew temp and steam temp, a PID will help you dial in a delicious shot of espresso, every time.

    In the Morning Maintenance video below Gail will show you how to program your PID on the Rancilio Silvia. The PID's we install on the Silvia will allow you to control the brew temperature, pre-infusuion time, pre-infusion wait time, and brew time.

    Once you know how to program your machine, it's fun to experiment with different temperatures and times for the same coffee. Each variable will bring out different flavors in your cup! Yum!

    Be sure to subscribe to our channel for more videos! Subscribe to our channel by clicking here!

     

  • Ask Andrew From Rocket: PID Design

    PID DesignBack with another episode of Ask Andrew! This time we decided to ask Andrew his thoughts on the design and use of a PID on an espresso machine.

    We all know that Rocket Espresso takes a lot of care when it comes to the design of their machines, both in their aesthetics and  functionality! So we were sure he would have some thoughts around the PID design.

    What's a PID controller you ask? A PID, which stands for proportional-integral-derivative, is a device that is constantly reading  the temperature of the boiler (or wherever a thermometer is placed). It continues to calculate and adjust the boilers heating element so that when you brew you can set and be confident that you are brewing at a specific temperature.

    Watch the video below to learn more about the PID design and it's part in the design of a Rocket Espresso machine!

     

  • How to Program an Auber PID on the Rancilio Silvia

    Rancilio Silvia with Auber PIDPerhaps more than any other home espresso machine, the Rancilio Silvia has a devoted, storied following. Originally designed by commercial espresso machine manufacturer Rancilio to give as a gift to their distributors, it quickly took on a life of its own and, for many years, was considered the go-to espresso machine for home enthusiasts who wanted to craft specialty coffee quality drinks.

    Owing to its creators, the Silvia featured largely commercial-grade components, which hadn't really been on offer for many home-class espresso machines before. With copper-plated brass internals, a 58mm standard chrome-plated brass portafilter and a traditional steam wand, it provides the tools you need to make excellent espresso-based drinks. But it does have one major design element that have caused some folks to deem it as 'finicky.'

    The Silvia is a single boiler espresso machine that employs a rather simplistic temperature regulation system -- a bi-metal thermostat that engages and disengages the heating element by bending one way or the other (as determined by the machine's temperature). So, if the machine is on the lower end of the temperature spectrum, a small metal piece will bend one way in order to make a connection and allow the electrical current to reach the element, beginning the heat up process. On the other side of the spectrum, once the machine's internal temperature reaches a high that causes this thin metal to bend in the opposite direction, it will interrupt the current and the machine will cease heating up. This is a very common method of temperature regulation used in appliances or thermostats around the home, and while it is cheap, reliable and effective, it also lends itself to a wide arc of variable temperature.

    When these temperature variables happen in your home, you put on a sweater; when they happen in your espresso machine, they can result in marked differences in shot quality. At the hottest end of the spectrum, your coffee will taste burnt and over extracted, while on the coldest end it will taste sour. One way you can ensure you're brewing at the right temperature, however, is to 'temperature surf' -- pull just enough cold water into the boiler to engage the heating element, then, after it's heated up to its highest temp, wait a bit (to allow the temp to come down from its hottest level) and then brew. Another way you can manage this is to circumvent the bi-metal thermostat altogether and install a PID!

    The PID will take over managing the boiler's temperature by using a more sophisticated and programmable electronic chipset. At SCG, you have the option of ordering a Rancilio Silvia from us that already has an Auber PID installed, which offers the ability to program the boiler temperature and elements of extraction such as pre-infusion and shot timing. In the video below, Gail shows us how to get into the Auber PID unit that we install on the Rancilio Silvia, navigate through it and program it for your specific needs.

    Yes, this was a rather extensive and detailed lead-up to a simple how-to video, but knowing is half the battle, friend. And the other half is brought to you by espresso.

    SCG How-To Guides: Programming the Auber PID on the Rancilio Silvia

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