Building an electric brewery

Wait, this is supposed to be a website about gaining insights into financial decisions for a secure retirement, right?  Where does brewing beer come into the picture?  The better question is, when doesn’t beer come into the picture!  Retirement isn’t about waking up at 10:00 in the morning and not going into work.  That’s what hangovers are.  Retirement is about spending your time doing what you like, and what you like should include your hobbies.

Hobbies have a way of eating away at your money, both before you retire and into retirement.  Take golf as an example, a round can cost you anywhere from $50 to, well, the sky’s not even the limit, the limit is somewhere in space by Mars.  Finding ways to lower the costs of what you like to do is a great way to have the funds to continue your hobbies into retirement.

Which brings us to brewing beer.  I can’t argue that I’ve saved money brewing my own beer versus buying beer, but with each batch I get closer to that.  Like most hobbies, it’s not about saving money, it’s about spending time with friends, building memories, and having a great time.  Still, saving money isn’t a bad thing.

Brew Day
Brew Day

The costs for brewing beer are all over the place, mainly because there are many ways to brew beer.  You can use a pot in your kitchen and ferment in a 5 gallon bucket, or you can buy custom stainless steel pots and conical fermentors.  No matter what equipment brewers use, brewers follow similar processes.  To make wort, the liquid that becomes beer, it takes water, grain, heat, hops, and cold.  To turn the wort into beer it takes yeast and time.

Looking at each item, there are opportunities to save money.  Instead of buying bottled water (assuming you have bad water), you can buy a filtering system and add the minerals to the water to get quality water.  Instead of buying grain in small quantities at huge markups, you can buy sacks of grain and mill it yourself.  Instead of using propane to heat the water, you can use electricity or convert your system to natural gas (if it’s available to you).  Instead of expensive hops you can try your hand at growing your own (they grow like weeds).  And instead of using a fridge to control fermentation temperature, you can put the fermentors in a cool basement and brew styles based on the varying temperatures during the different seasons of the year.


Like everything in retirement, you can see why there are so many options out there, since there are no right answers for everyone.  You might not have the space to store grain, you may not brew often enough to justify buying a grain mill, you might not have a basement, or natural gas.

The last point is where my story starts.  In a previous house I had plumbed quick disconnect ports for natural gas so I could brew in the garage or in the back of the house.  When I brewed I didn’t even notice a blip in my gas bill.  Then I moved to an area without natural gas (part of the reason I installed a ground source heat pump) and began brewing with propane.  Brewing with propane is not only a pain, but it’s expensive.  I was using around $7 in gas each time I brewed, while I was spending around $20 in other ingredients.  My heat source was a third of the cost of my ingredients!  Something had to change, so I began construction of an electric brewery.

Control Panel
Control Panel

There are a few benefits to an electric brewery.  The first is, like an oven, I can set the temperature I want something to be and walk away.  Somehow I rarely ever managed to hit the correct temperature when using gas, and I’d inevitably be adding ice to cool things down.  The second is I can’t ever run out of fuel.  There’s also something great about knowing I’m brewing with the sun, since my electricity is coming from my solar panels.  Finally, I can throw a lot more heat into a single pot using electricity than using gas.  I can’t stack burners on top of each other, but I can put more than one element in a pot.

The main con with electric brewing is the cost of building a control panel.  I pretty much went all out, and spent around $1,000.  While that’s a lot, I also sold my gas equipment, bringing the total cost to around $460.  At $1,000 it would take me 96 brews to break even, and at $460 it would take 44.  It’s possible to build a panel for less, but here are the details behind my build.

Control panel internals
Control panel internals

The basics of an electric brewery are a water heater element (regular or stainless) and an electrical source.  The reason for the control panel is to safely turn the element on and off.  Just like your stove and oven don’t use an on/off switch to control the temperature, neither does an electric brewery. What is needed is a way to regulate how often the element runs.  Think of your heating system, it’s basically either on or off, but you have a thermostat that controls how long it’s on and off.

Sometimes it is useful to think of electricity as water to understand the relationship between watts, amps, and volts.  With electricity you have watts (how much work the water can do flowing over a water wheel), amps (how fast the water is moving), and voltage (the pressure in the pipe).  In the United States, houses typically have 2 120V lines that can be combined together to get 240V.  Power = Voltage * Amps.  What this means is if you plugged a 5500 watt element into a 240V outlet, it would draw 5500/240=22.92 amps.  If you plug that same element into a 120 volt outlet you might think it would draw 5500/120=45.8 amps, but it wouldn’t because of the resistance of the element.

If you care about why, it’s because of another law, Power = Voltage ^ 2 / Resistance (ohms).  To solve for R(esistance), we have 5500 = 240 ^ 2 / R, or  57,600 / 5500 = 10.47 ohms.  Now we know the resistance of the element, so we can change the equation to solve for 120V, Power = 120 ^ 2 / 10.47 = 1,375 watts.

Not everything has such resistance though.  A 1/25 horsepower pump with a 120V motor might draw 1.4 amps, but a 1/25 HP pump with a 240V motor would draw 0.7 amps.  Why this is important is because higher amps need thicker cables, and thicker cables cost more money!  This is the reason electric brewers typically install 240V outlets; they can get more power out of a wire of a specific size than they could using 120V.

It’s usually easier to start with off the shelf components, so a I began with a 50 amp GFCI breaker from a spa panel and a 4 conductor 50 amp stove/dryer outlet.  Working backwards, I needed a way to get the elements into the pots.  There are a lot of ways to do this, but I went with a Hotrod heat stick.  The beauty of this thing is I can move it from pot to pot depending on the batch size I’m brewing, or put two in one pot to raise the temperature faster.  Once I had these parts, it was time to work on the control panel.

The basics of most panels are similar.  You need a way to get power from the outlet to the elements.  Because of the high voltage and amperage involved, different types of relays are used.  The first type is a contactor, commonly used in air conditioners because of their ability to handle high loads.  The problem with contactors is that they’re mechanical, and like all things mechanical, can only switch on and off a finite number of times.  Since an element might cycle on and off many times a minute, a contactor might not have a very long lifespan.  To get around this, another type of relay is used, a solid state relay, or SSR.  These relays use light to open and close the switch, and should have a longer lifespan.  They’re also a lot less expensive than a mechanical relay.  A standard relay is the last component home brewers can use in a control panel.  Typically smaller relays can’t handle a lot of power, but they’re great for small things like pumps and lights.  A relay board with 8 relays can cost about the same as a single SSR.

Control panel switches

Now that you have a power source, switches, and elements, you need to connect everything together.  Some brewers don’t bother with this, and instead use just an on/off switch or a lower wattage element that manages to maintain the correct temperature.  If you have a consistent brew size, this is an option.  I don’t, so I needed to add some logic.  There are two ways to do this.

The first option is to use a PID controller.  These devices range in price from $20 to $150 each.  You need one for each element you have in your system.  I built my system to have three elements, which means I’d need three PID controllers.

The second option is to learn some rocket science and use a computer such as the Raspberry Pi, which costs around $40.  The Raspberry Pi is a computer with pins that can be turned on and off via software.  The most amazing thing is a guy named Doug Edey has created free software for the Raspberry Pi called Strangebrew Elsinore Server that serves as your interface to your system.  Getting the software up and running is pretty straight forward, but can be challenging if you haven’t worked in Linux before.

Click here for the step-by-step instructions I created while setting mine up.

Once the software is installed, you can connect all of the wires to your system.  While the Raspberry Pi has enough power to turn on a low-powered relay or SSR, it doesn’t have enough juice to run multiple components at one time.  The way around this is to use a Darlington array.  A Darlington array is like another relay in that it allows a small power source to turn on a larger power source.  So now you have software turning on a pin that turns on a Darlington array that turns on an SSR that turns on an element.  Since SSRs can fail in the on position, I recommend using an SSR for each 120V hot leg of your system, and a contactor before the SSRs to act as a master power switch.  Better safe than sorry!

A Darlington array is interesting because how it works is a little counter-intuitive.  Normally when a pin on a Raspberry Pi turns on it goes to +3.3V.  When it shuts off it goes to 0V.  When power is applied to a pin on a Darlington array, the opposing pin doesn’t go to any volts, but rather the the pin connects to the ground.  What happens is it completes the circuit.  If that doesn’t make sense, hopefully this diagram will help.  I only showed wiring up one hot leg of the power to the element to keep the diagram simple.

Pi wiring
Wiring diagram

All of your 1-wire bus devices are connected to +3.3V, ground, and GPIO 4 (for data).  When the software applies power to GPIO18, the Darlington array connects the ground from the SSR, allowing the +5V to flow to the ground, completing the circuit (electricity flows from positive to ground).

Darlington Array
Back of the board
Back of the board
Control board
Sections of the board
Wiring up the board
Wiring up the board

There are many different ways to build an electric brewery, but hopefully this guide gives you a few ideas.  No matter what your hobbies are, it’s always worthwhile to take a step back and see if there’s anything new you can learn that will make your hobby more enjoyable while saving some money too.  Prost!


If you have any questions or comments, you can reach out below or continue the discussion in the forum.  If you are interested in receiving a notification of new posts, you can subscribe here.


  1. I would be really interested to know exactly how you assembled the darlington array. I’m in the process of building a panel to control 4 elements and having enough power from the pi board to the contactors is a major issue I’m trying to solve.


      1. This is the first time i’ve attempted anything like this so any detail information I could get would be very appreciated. I ordered the stuff last night to build the board like you show it so the assembly instructions on that would be great.


          1. The picture helps a lot. Thank you very much!

  2. On the wiring diagram, when Raspbery Pi decides to turn the first element on, pin GPIO18 goes positive. Do all 7 pins of Darlington go positive all at once allowing up to 7 outputs simultaneously when 18 is positive?

    When do the other pins, GPIO23, 24, etc go positive? Are they controlled separately?

    Do each output 23, 24 require a separate Darlington?

    Appreciate your response


    1. In my example, when GPIO18 goes positive, only the corresponding pin on the Darlington array closes and completes the circuit (and only GPIO18 goes positive). If you wanted all 7 pins on the Darlington array to to power up with 1 GPIO pin going positive, you’d need to jumper pin 1 to pin 3, 5, 7, 9, 11, and 13.

      Mine is wired up something like GPIO18 going to pin 1, GPIO23 going to pin 3, GPIO24 going to pin 5, GPIO12 going to pin 7, and GPIO16 going to pin 9. I have everything controlled separately. In the software you can make a switch control any GPIO. You only need one Darlington array per 7 switches.

      Let me know if that helps.


  3. Thanks for the quick response.
    My understanding of computer interface was zero before reading your article, in fact I had no clue what a Raspberry Pi was.

    So, Raspberry Pi can be programmed for each of its outputs separately and each output connected to a pin of Darlington for amplification so it can drive an SSR?
    That means I can time the mash for 48 mins and then ramp the heat up using a second element or bypassing the PIN of the first stage

    If I am not taking too much of your time, here is another function I need out of Raspberry Pi
    Display mash temp with big bold letters independent of PIN.

    Thanks in advance.


    1. The beauty of the Raspberry Pi is that you can make a GPIO work as in input, or as an output. An input would be a temperature probe on the 1-wire bus, and an output would be powering on a leg of the Darlington array. You can make each input do something unique, each is controlled by the software.

      The key is the software, and the Strangebrew software can be configured to do what you want in regards to driving an SSR and displaying the temperature from any 1-wire temperature probe. You’re pretty much limited by your imagination.


  4. Thanks for a great very enlightening article. This topic hit home with me because it had the information I was looking for in a format Easy to understand and follow. I hope to build just such a electric brewery in 2017.
    Happy New year


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