Using a 26 gallon beer brewing kettle to make cheese.

[Sweet Leaves Farm]

I looked at Wayne's setup, and if I could be certain about the wiring, I would like that idea. I could even let the water heat while I was out milking, then just pop the can in the warm water and start stirring. I bet John could whip up a controller that would make it all work. I need to figure out a good way to mount the elements, so we wouldn't have any chance of ZAP!
If I use the band heaters, I would buy the 3000 watt one, and just wire up a double breaker, we have room in the electric box in the garage. With the water heater elements, I would need to
do that anyway.

[pastpawn]

I looked at Wayne's setup, and if I could be certain about the wiring, I would like that idea. I could even let the water heat while I was out milking, then just pop the can in the warm water and start stirring. I bet John could whip up a controller that would make it all work. I need to figure out a good way to mount the elements, so we wouldn't have any chance of ZAP!
If I use the band heaters, I would buy the 3000 watt one, and just wire up a double breaker, we have room in the electric box in the garage. With the water heater elements, I would need to
do that anyway.

I highly recommend a GFCI breaker.  240V 30A GFCI breakers are expensive, but they are worth it.  I put one in my breaker box when I built my electric brewing system.  Make sure that the boiler is grounded. 

[Sweet Leaves Farm]

Andrew, we have a whole house GFCI and all the breakers are GFCI also, they are the only ones that fit in the box. As for grounding the metal stand, would having it set on the concrete floor be enough, or would I have to do something else? The ground rod for the house is buried in the footer for the garage.

[pastpawn]

Andrew, we have a whole house GFCI and all the breakers are GFCI also, they are the only ones that fit in the box. As for grounding the metal stand, would having it set on the concrete floor be enough, or would I have to do something else? The ground rod for the house is buried in the footer for the garage.

If there are electrical stuff connected to your pot, the metal pot needs to be connected to a ground in your house.  It's the green wire in the house wiring.  You can run a piece of bare copper wire from the pot to an outlet.  Without grounding, the breaker won't trip if there's a short in the pot.

[John@PC]

If there are electrical stuff connected to your pot, the metal pot needs to be connected to a ground in your house.  It's the green wire in the house wiring.  You can run a piece of bare copper wire from the pot to an outlet.  Without grounding, the breaker won't trip if there's a short in the pot.

Andrew is right (as usual) but in the case you do use a band heater I would expect the metal band to be grounded.  GFIC's will not trip if you have a hot-to-neutral (black to white) short; only if it's across ground.  Note that I have not tested this personally  so I can't attest.

[smolt1]

You are correct John, The the ground fault interrupt only protects a fault to ground ( like through your body ). It cuts the current off very fast when it gets to a few mill-amps to ground. The regular breaker cuts the current off when it gets to the rated current ( 20 amps for a 20 amp breaker ) to keep the # 12 ( 20 amp rated )wire from over heating. One saves you, the other saves your house.   

[Sweet Leaves Farm]

So here's the compromise that I, with all of your help came up with:  Notice that after doing the math, I realized I needed to scale down the pot to 15 gallon.  Any comments are appreciated!

[Sweet Leaves Farm]

Would this work for the temperature controller for the 5500 W heating element? It looks OK, but maybe I'm missing something...

[pastpawn]

You might need a small pump to stir the heating water.  The heat will raise to the top, and the temperature controller won't work right at all.  The difference between above and below the element can be VERY large.  I know you'd think that there'd be some convection currents to move the water around, but that just doesn't happen. 

Also, there's only one completely SS element that I've seen.  The ones that you get at home depot that look stainless usually have iron bases that do rust inside the pot.  I'll see if I can track down the full SS one for you. 

[awakephd]

Hmm -- thought I had replied, but must have done something wrong.

Yes, the temperature controller can handle this IF you switch the power to the 5500 watt heater element through an external SSR (solid state relay). At least for the digital PID controllers I've seen, the built-in mechanical relays that come with some models are only capable of a few amps. And in any case, the SSR should give you better long-term reliability.

I agree with Andrew about the pump to circulate the water!

[pastpawn]

This might seem expensive, but it has the PID, thermocouple, SSR,  heat sink, Emergency Stop, 10 gauge power cord, a switch and dial to go from temperature control to % power (for boil). 


http://www.amazon.com/gp/product/B00K67ZHHS

[Sweet Leaves Farm]

I found this to help cut costs :http://www.instructables.com/id/Electric-brewing-system/#step0

Looks just like the one from Amazon, but should be a little cheaper, and my dad (40 year custom HVAC experience)and hubby (physicist for test and measure)can make sure I'm doing it right.

I will definitely add a pump to circulate the water.

Should the thermometer be in the water jacket or the milk? I thought it should be a food safe one in the milk, but maybe not?

[pastpawn]

Water jacket.  Otherwise you will probably have overshoots in temperature. 

This is a control system.  The PID parameters should be tuned to produce the quickest heating cycle without overshoot.  This can be done manually, but by far the easiest way to do that is to look at the PID manual and see if it supports an "autotune" feature.  The way that should work is to set the system up exactly the way you want to use it (just use water for milk), with all the same quantities, and with pumps etc running, then put the PID into autotune.  The PID will heat up and monitor the response at the thermometer, watching for overshoot, then repeat.  It can take a while, but in this way the PID will set it's P/I/D parameters to the ideal. 

Should the thermometer be in the water jacket or the milk? I thought it should be a food safe one in the milk, but maybe not?

[pastpawn]

I found this to help cut costs :http://www.instructables.com/id/Electric-brewing-system/#step0

Looks just like the one from Amazon, but should be a little cheaper, and my dad (40 year custom HVAC experience)and hubby (physicist for test and measure)can make sure I'm doing it right.

I will definitely add a pump to circulate the water.

Should the thermometer be in the water jacket or the milk? I thought it should be a food safe one in the milk, but maybe not?

A couple comments on that instructables build:

• That PID does have an autotune feature.
  Don't use a dry cord if you are going to plug/unplug this often.  Fixed installation, it will be OK.   Dryer cords are a huge hassle.  Get some SJOOW cable from Home Depot or electrical supply and add a connector.  Dryer cords don't bend well at all. 

[Sweet Leaves Farm]

Cool. Thanks! Now to finish cleaning and organizing the garage, so I can start putting up the wall in the next few weeks.