Boil Control for Electric Brewing

[butterball1121]

I just switched my homebrew setup from propane to electric (5500 W element in BK and HLT).

I previously used an Arduino to control the propane burners for my HLT and BK (combo of 5V relays, 120:24V furnace TX, and furnace gas valve)

I am reusing the Arduino because it will keep most of my brewing process the same, just some minor tweaks for electric element control (PID) instead of gas valve control (hysteresis).

My only hang up so far is boil control.
I've searched and searched and its seems everyone switches from auto to manual mode with a standalone PID (like Auber), which I am obviously not going to do because I'm using an Arduino, or switches to PWM control using a homemade circuit with a potentiometer.

Are these the only two options that anyone is using?

My control box is rather clean looking and I think the software path is more elegant, so i'll write the code to use an up/down button in manual mode before I add any knobs. But ultimately I prefer something that gives me consistent boil/evaporation rate regardless of ambient temp or batch size (5/10 gal).

Anyone using any other methods with success?

 

[ancientmariner52]

The reason everyone uses manual control for boiling is that there is no practical way for a sensor to monitor boil conditions. To change water at boiling temp to steam at boiling temp requires a huge amount of energy. It requires 1 BTU of heat to raise the temperature of 1 lb of water 1°F. Until you reach boiling temp. At sea level atmospheric pressure, it takes another 970 BTU/lb to boil, but the temperature doesn't rise! This is known as latent heat of vaporization. Therefore, a temp sensor can't tell what's happening in the kettle. Commercial boiler controls sense pressure, but we can't use that in an open system. Sorry for the long winded thermodynamics lesson, hope this helps.

 

[SanPancho]

as noted above, boil control isnt really an option. your best bet for consistency is to just make your own boil power level. go to boil, then back it off to 70% power. use that same power level and there's your consistency for ya. too much boiloff? try 65., etc. you'll dial it in soon enough.

 

[butterball1121]

I understand the impossibility/difficulty with using a temp or pressure sensor, respectively.

I guess I was just thinking something more calculated than trial and error with a predetermined %.

For example, set the PID to 208, let the temp stabilize at 208, and then used the 208 degree % and add 5%. In my mind this would at least be slightly adaptive for ambient temp and very repeatable.

I've also seen some tables that list evaporation rate based on percent power and batch size. So you could actually use a BK element % based on gravity of preboil in order to hit your post boil gravity.

 

[SanPancho]

As was explained to me, once we hit boil we back off the power to the elements because once the wort is at boil temp the wort adjacent to elements will volatize, losing the contact between wort and elements and then overheating and burning up elements. This is for a 2.5bbl kettle. My first electric system. I asked alot of questions.

 

[SleepyCreekBrews]

I think you'll find everyone does it manually.
My procedure: after the element is covered, turn it up to 20 Amps , Once it boils I generally have to kill it a couple times to avoid a boil-over during hot break, and then turn it down to 13 amps where it does a rolling boil for the duration.

 

[butterball1121]

I think you'll find everyone does it manually.
My procedure: after the element is covered, turn it up to 20 Amps , Once it boils I generally have to kill it a couple times to avoid a boil-over during hot break, and then turn it down to 13 amps where it does a rolling boil for the duration.

I read that some switch to manual and turn down the element from 100% after hot break, while others set a PID to 208-210 and then manually take the element up to gently reach boil.
Sounds like you turn it down after hot break?
13/20 amps (65%) seems consistent with what I've read for boil % for a 10 gal batch.
also read (40-45%) for 5 gal batches.

Are 65% and 40% good starting points for 10 and 5 gal batches if i were to trial and error it?

 

[butterball1121]

As was explained to me, once we hit boil we back off the power to the elements because once the wort is at boil temp the wort adjacent to elements will volatize, losing the contact between wort and elements and then overheating and burning up elements. This is for a 2.5bbl kettle. My first electric system. I asked alot of questions.

This makes me think reducing the element power before boil is better than reducing it after hot break.

 

[SleepyCreekBrews]

I read that some switch to manual and turn down the element from 100% after hot break, while others set a PID to 208-210 and then manually take the element up to gently reach boil.
Sounds like you turn it down after hot break?
13/20 amps (65%) seems consistent with what I've read for boil % for a 10 gal batch.
also read (40-45%) for 5 gal batches.

Are 65% and 40% good starting points for 10 and 5 gal batches if i were to trial and error it?

The brewers that use the Auber EzBoil ramp up the temps to just below boil temp with the PID, and then switch to manual mode for the boil. This has the benefit of not having to watch the kettle during ramp-up, and avoiding boil overs.
I turn it down immediately when it reaches a boil.
And Yes, 65% is prolly a good starting point for boil power for a 10 gallon batch (same as me)

 

[Horseflesh]

My system lets me configure a boil target temperature at which it cuts power from 100% to whatever percent I specify. In warm or cold weather, boil-off is very consistent.

Since you can program your own method, play around and let us know how it goes... But I have zero complaints with the simple algorithm that is in common use.

 

[mabrungard]

I use one of these in my system to control my boil kettle.

https://www.auberins.com/index.php?main_page=product_info&products_id=444

I can't say enough good things about it and it's inexpensive. Just add a SSR to your circuit and you're good to go.

 

[augiedoggy]

I just switched my homebrew setup from propane to electric (5500 W element in BK and HLT).

I previously used an Arduino to control the propane burners for my HLT and BK (combo of 5V relays, 120:24V furnace TX, and furnace gas valve)

I am reusing the Arduino because it will keep most of my brewing process the same, just some minor tweaks for electric element control (PID) instead of gas valve control (hysteresis).

My only hang up so far is boil control.
I've searched and searched and its seems everyone switches from auto to manual mode with a standalone PID (like Auber), which I am obviously not going to do because I'm using an Arduino, or switches to PWM control using a homemade circuit with a potentiometer.

Are these the only two options that anyone is using?

My control box is rather clean looking and I think the software path is more elegant, so i'll write the code to use an up/down button in manual mode before I add any knobs. But ultimately I prefer something that gives me consistent boil/evaporation rate regardless of ambient temp or batch size (5/10 gal).

Anyone using any other methods with success?

sounds like you have the same ability but I use an arduino which controls an ssr for each one of my elements and I just switch from "PID" mode to pwm mode within the brucontrol software which allows you to control the same output a number of different ways (not at same time)
I did calculate my boiloff rate vs size and power over the first couple brew sessions and use those 2 numbers for my 2 sizes of brew sessions.