The PID Controller Myth In Your Electric Brewery
When I first started homebrewing, all I had was a mash tun and a BBQ thermometer on a stovetop, and I would try to find the right setting on my stove to maintain the right temperature. It wasn't easy, and I thought there had to be a better way.
Over the years, I've experimented with many types of temperature control methods for homebrewing. I've used PID controllers and switching controllers and I'll do my best to explain the differences, as well as the pro's and cons of both. With the increasing popularity of electric brewing it is now possible to maintain the tightest control possible over your mash temperature, but the question is, is it really necessary to maintain 'perfect' mash temperature, and how precise must it be?
PID acronym is Proportional, Integral, Derivative. PID controllers are the most precise controller you can use, PID controllers can maintain extremely tight temperature range, with little to no overshoot. I've used PID's extensively, and can attest to the accuracy that these controllers will deliver. For maintaining the tightest control over temperature, these will be your answer.
The downside to PID's is that precision comes with a compromise and the controller needs to be 'tuned' every time you change your brewing recipe. If you are like me, you like ALL kinds of beers, lagers, stouts, IPA's, double IPA's, you get the picture! Programming a PID isn't easy, and every time your recipe changes, or the volume of liquid changes, you'll need to re-program the unit. While not always the case, PID controllers tend to only offer heating capability, and cannot be used for controlling fermentation. PID's are great if you like to tinker and learn all about the settings that they offer, but it is possible to spend more time trying to 'perfect' your settings than actually brewing!
Single or Dual Stage Temperature Controllers
A single stage controller can control either a cooling, or heating device. A dual stage controller can do both. These type of controllers are extremely simple to set up, with no complicated algorithm, just on/off switching to control temperature. Dual stage controllers are very practical, because they can be used to control a heating element and also manage a fermentation control device without reprogramming. Our own Bräu supply SV120-ETC dual stage controller can 'auto switch' meaning that you can plug in a heating device, and a cooling device and it will maintain tight temperature control or 'differential' between the two. The differential is adjustable depending on your needs of control. This makes it ideal to use it in a fermentation environment where the temperature of your room varies and you need to heat and cool, depending on the time of the day.
The downside to this type of controller is the potential for temperature overshoot. This can be minimized by sizing your heating or cooling device appropriately, and programming the temperature differential to cycle more frequently. When brewing at 120V, the temperature overshoot is around 1 degree, which is hardly a problem for most, and the simplicity of the design allows you to be up and running in minutes.
Our SV120-ETC brewing controller can also be paired with the SV240 brewery controller for those who want to brew with 240 volts. This controller essentially 'steps up' the voltage to 240V and provides a variable output. Dead simple to use, it safely regulates the output and makes it even easier to maintain perfect temperature. This method gives the user the flexibility to separate the SV120-ETC and use it to control in 120V, and also manage up to a 5500W brewing element. To maintain mash temperature with no temperature overshoot, the user simply needs to turn the dial until the set temperature is met.
Above is a shot of the SV120-ETC and an SV240 controller used together to fire a 5500w element in our Unibräu Pro system.
The EZboil controller we offer is a sort of hybrid controller. It maintains temperature in the same way that our SV120-ETC controller does, but uses a solid state relay for the switching relay. As the set temperature nears, it begins to pulse the electricity to the element, thus preventing overshoot. The EZboil isn't as easy to set up, but it's still infinitely easier than a PID to program, and it features a built in timer. The EZboil can only be used for heating functions, and so isn't as versatile as our SV120-ETC, which can
So which type of controller should you use?
If you ask me, after using analog controllers, PID controllers, EZboil controllers from Auber instruments, and ETC switching controllers I will say this. The easiest controller I've ever used is our SV120-ETC. It's simple, reliable and maintains 'almost' perfect temperature. I like brewing, not programming. I want to plug it in, turn it on, and brew! If you are after precision and don't mind programming, then a PID is your obvious answer, but how much is your time worth? And I challenge you with this question. Will your beer taste better because you maintained your mash temperature to the tightest of tolerance, vs. maintaining your mash temperature to within a degree of your 'ideal' temperature? In my own personal experience the answer is NO! There are so many factors that affect the quality of your brew, not least important maintaining ideal fermentation temperature.
How much does a degree of overshoot matter? Well, it depends on who you ask. I used to believe that it meant a great deal, yet my perception of that has changed. There is a great article about mash temperature and efficiency here, on the brulosophy.com website and I love the way they challenge the conventions of brewing. Marshall Schott the author of the article, has done many experiments and has come to believe that mash temperature may mean less than we previously thought. That doesn't mean we should let the temperature fly around, but let's spend more time working on other aspects that make a great beer great, and worry just a little bit less about 1/10th of a degree!
What I do know is with our range of temperature controllers, you will enjoy the brew process, and you won't get frustrated trying to 'dial' in your controller. And best of all, you'll make fantastic beer. After all, isn't what this is all about?
That's it for now, and I want to thank you for taking the time to read this article. Please feel free to share it and comment, your feedback means a lot to us.