Building a HERMS Brewery: Part II

A couple of weeks ago, I posted about my plans for building a HERMS home brewery.  I wanted to post a follow-up with some updated photos and a little video since I have changed it up slightly.

Below is the finalized wiring diagram.  Since the control panel is mounted on top of a shelf, I didn’t want any wires coming out of the bottom, so the power in comes from the spa panel to the right, and the power goes out to the kettle to the left, as does the temperature probe wire.

HERMS wiring diagram

Note that the wires running from the PID to the Solid State Relay (SSR) are not shown, because I had to look at my particular PID to see which terminals they were supposed to connect to.  You’ll also notice the large empty space to the top left.  That is there so that I can eventually add an additional contactor that will allow me to run another heat element for the boil kettle.  For now, the boil kettle is propane fired, but I have the ability to convert to electricity if desired.

Additionally, I have a simple electronic timer that I will eventually install that will allow me to set it up so that it will automatically turn on at a given time.  For example, I could set the strike water to start heating at 8am, so that when I get up between 8:30 and 9am, I’m ready to mash in! Yay for saving time on brewday!

The spa panel is mounted to the right of the control panel, and the 240v power cord comes into the spa panel where there is a breaker to serve as a a way to turn on/off all power to the system, as well as a GFCI.  I mounted the spa panel and the control panel on a shelf connected to the system by a hinge.  This places all of the electronics slightly higher than the level of the rest of the brewstand, and allows water to run off the table top before getting to the electronics.  You never know when you might spill and fry all of the electronic parts, so I wanted to be as safe as possible.

HERMS control panel HERMS control panel

The hinged shelf allows me to fold it all up when not in use and save some space.  The brace is also on a hinge, so it can provide some support to the shelf as well as fold up into the compact footprint of the full system.

The PID controller allows me to set a temperature and circulate my strike water, and then my mash, through the coil and past the temperature probe, which tells the PID when to send a signal to the heat element and heat the water in the HLT.  It allows for very precise control of the system to make sure that I can hit and maintain the mash temperature.

HERMS wiringIn the picture above, you can see the outlet for the pump on the right side of the control panel.  It is powered by a simple toggle switch.  The empty hole on the top of the box is where the fan was eventually mounted (after the photo was taken).  It blows directly onto the heat sink on the SSR to keep it from over-heating.  The fan (and eventually some lights) are powered by through the DC power supply (phone charger) in the bottom right corner.

Now that we’ve covered a lot of the fun electrical things, below is a video of the HERMS in action.  I have annotated it with some notes on how everything works and how the water is pumped through the system and the mash is kept at the right temperature.

What type of system do you use?  I’ve seen all sorts of things, from the stove-top extract system, to the 3-tier gravity system, to the Brutus 10, HERMS and RIMS systems, and everything in between.  It is great to see the DIY attitude and ingenuity of all of the homebrewers in the area – as it makes for a vibrant and fun community with lots of great beer to try!  Speaking of which – don’t forget the Homebrew, Pint Glass, and Craft Beer Swap party at Big Boss on Sunday April 1st!




Things to note and upgrades coming soon:
1) The large empty space in the top left corner of the box is so that I can add an additional contactor and eventually use an electric boil kettle.

2) I will be adding “armed” and “firing” lights for the heat element, as well as a larger “power on” light.

3) I have a timer that will be added in the top left corner of the face of the box so that I can have the hot water start heating at a set time so that once I’m ready to brew, I already have hot water.


Was wondering if you have a list of parts that were used for that control panel, I want to make something just like it.


I don’t have a parts list all put together in one place at the moment. But the key components inside the control panel are:
Power Source
Pump switch
Heat element switch

Outside of the control panel we have:
Spa Panel
Temperature probe
Wire with Male/Female plug/connector to easily connect/disconnect the kettle
5500w heat element

Shoot me an email if you need any specific info on any of the parts and I can probably pull it up for you.

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