Decided to build an electric system just to heat water and boil wort, with a 5500W heating element, 240V.
I use a stirring system to minimize scortching and increase efficiency. It is working just fine, I can heat my strike water from 70 to 170F in 10min, boil from 150F in 15min.
One late addition I have to do was a PWM controller to be able to manually control the boil intenssity. This was achieved with a very simple circuit I first used 20 years ago while still in college. It is basically a ramp generator feeding a voltage comparator, in which you control the reference voltage. The duty cycle I use for brewing purpose is about 4s, adustable from 2 to 6s.
I can share the project if anyone is interested.
PWM board.
SSR fan, RTD input and load output.
From left to right, dual phase power input green lights, controller, top dial for PWM power control, load on/off switch, load dual phase lights.
Air intake for SSR cooling.
Connected to kettle.
Heating element.
Stirring.
Bottom switch is the sound alarm on/off. Shown red light high alarm going off.
AC power plug.
Guts. Right up corner is a 12VDC switched power supply for the cooling fan and buzz.
Timer.
Clean back, easy access.
Basically, what this system does is allow me to heat the strike and sparge water to exact temperatures, reach a full boil and control the boil using the PWM power control. I have the controller alarms set to high 210F and low 70F. When alarm high is triggered, light and buzz goes off to let me know that boil is imminent so I can manage it with PWM adjust. The low alarm is used when I'm cooling the wort for pitching, so I know it is cool enough.
Videos:
First test run, showing the boil alarm going off at 210F.
First brew with this system, boil with PWM control.
