My 20 gallon electric kettle

Here's the latest in my quest to eliminate propane/natural gas from my brew day. This kettle will accompany my big ass boiler in a yet-to-be-constructed rig. The welded fitting came from Bargain Fittings, and the element is a 5500W Camco ultra low watt density unit that I found at Amazon. Here are the test results with approximately 18 gallons of water in the kettle:

0 mins - 85° F (tap water in south Texas is WARM!)
10 mins - 108° F
20 mins - 130 ° F
30 mins - 149° F
40 mins - 168° F
50 mins - 183° F
60 mins - 196° F
70 mins - 204° F
80 mins - 209° F
82 mins - 210° F (boiling at 1,000' MSL)

Though the test case took an hour to get to boiling, it will take significantly less time to achieve a boil in practice, as the mash will hit the kettle at 160-180° F. Also, the inefficiency of an uninsulated kettle is obvious in my test results. The heating rate decreases dramatically as the water temperature increases above room temperature. A little insulation should really help. I plan to control the element with a microcontroller, a solid state relay, and a simple algorithm using pulse-width-modulation.

Is that ground well water or city water at that high of a temperature?
I just checked yesterday the well water as I changed the water in the Coi pond and my well water at 32' deep it's up to 63.2*F and drops down in the winter to 60.7*F maximum. Some years less of a swing in temps by 1 to 1 1/4*F.
This test of yours was done with 240 volts I assume not 122 volts this correct Yuri?

It's city water through a hose that sat in the sun all day (no, I don't use the garden hose for brewing, but for a simple test, it was the easiest thing to use).

It's plugged into a 220VAC, 50A outlet.

Looks very promising. Think I have the same element in my BK which makes me interested. Do you think the steel table it was sitting on affected boil times?

I'm going with 3/4" Buna-N closed cell foam insulation from McMaster (#9349K3) for my electric kettles. I believe Bobby found it.

It's rated to 220F, the insulation factor is very good, and, since it's closed cell, it won't absorb stray wort. One $26 sheet should insulate two kettles with the help of some aluminum foil tape.

It was sitting on two silicone mats to minimize heat transfer to the workbench.

Yuri_Rage said:

Here's the latest in my quest to eliminate propane/natural gas from my brew day. This kettle will accompany my big ass boiler in a yet-to-be-constructed rig. The welded fitting came from Bargain Fittings, and the element is a 5500W Camco ultra low watt density unit that I found at Amazon. Here are the test results with approximately 18 gallons of water in the kettle:

0 mins - 85° F (tap water in south Texas is WARM!)
10 mins - 108° F
20 mins - 130 ° F
30 mins - 149° F
40 mins - 168° F
50 mins - 183° F
60 mins - 196° F
70 mins - 204° F
80 mins - 209° F
82 mins - 210° F (boiling at 1,000' MSL)

Though the test case took an hour to get to boiling, it will take significantly less time to achieve a boil in practice, as the mash will hit the kettle at 160-180° F. Also, the inefficiency of an uninsulated kettle is obvious in my test results.

Click to expand...

I hope you don't mind Yuri as I want to use your times to temps for my two 5.5KW elements each in my HLT, MLT and Boil keggles in the future as I will have 19 plus gallons at the start of the boil. Your times will answer my heating times more accuractly plus I will insulate a three keggles.
The only difference i'll be starting off with lower water temps out of the well hence longer times to strike temps.

Yuri_Rage said:

I plan to control the element with a microcontroller, a solid state relay, and a simple algorithm using pulse-width-modulation.

Click to expand...

Hi Yuri,

I am working on a similar project in which I hope to control a 5.5kw element with an arduino board and relays. My question is how will you control the element with just 1 relay? Won't you need one for both legs?

Sorry, that was a misspeak on my part. Proper control will require two relays as psyber describes.

Yuri_Rage said:

Sorry, that was a misspeak on my part. Proper control will require two relays as psyber describes.

Click to expand...

Drat! I was hoping you knew some kind of trick.

Why 2 relays?, 1 SSR should do the job unless the second is for element isolation.

kladue said:

Why 2 relays?, 1 SSR should do the job unless the second is for element isolation.

Click to expand...

Yup, only one relay/SSR is necessary to control a 240v element. And, if you're worried about complete 240v isolation, one double-pole (DPST) relay will do the job.

So long as I have a GFI, I'm not worried about complete 240v isolation. 120v is much scarier than 240v in a wet environment...

I was considering complete isolation, given that the ground is tied directly to the exterior of the kettle. Is that being over-cautious?

Also, I've never seen a double pole SSR (they may exist, I just can't find one).

Yuri_Rage said:

I was considering complete isolation, given that the ground is tied directly to the exterior of the kettle. Is that being over-cautious?

Click to expand...

You can never be too cautious around electricity, but I don't fear 240v in a wet environment so long as a GFI is in use. 120v is much more dangerous because it has a higher risk of cardiac arrest.

I know Pol and others have installed a DPST relay on their rigs to completely isolate the 240v hot lines if necessary, but I feel that is overkill. If it's in use and shorts to ground, the GFI is your saving grace, not the DPST.

Yuri_Rage said:

Also, I've never seen a double pole SSR (they may exist, I just can't find one).

Click to expand...

Ya, it's called an SSRD. They're not very common, but they do exist.

Or, You can save yourself the trouble of dissipating heat over a second junction and use a contactor for your isolation.
Electrical > Starters and Contactors > Magnetic Contactors > Contactor,20a,2pole,Dp : Grainger Industrial Supply
Energize with with an HOA switch and then you can use 1 ssr to control your power output.

lamarguy said:

If it's in use and shorts to ground, the GFI is your saving grace, not the DPST.

Click to expand...

This seems like the proper train of thought. Guess I'll save myself $15 for a second SSR.

CodeRage said:

Or, You can save yourself the trouble of dissipating heat over a second junction and use a contactor for your isolation.
Electrical > Starters and Contactors > Magnetic Contactors > Contactor,20a,2pole,Dp : Grainger Industrial Supply
Energize with with an HOA switch and then you can use 1 ssr to control your power output.

Click to expand...

CodeRange; the contactor is ok for isolation of power to your control panel but is useless if your using it for controlling the heating elements as the pulse on and off times would have that relay chattering to no end unless if a controller were used to automate your temperatures in your keggles. You would have to manually switch the contactors coil and this is about as cave man as you can get in brewing. You would not have any tempeterature control of your heating elements without the SSRD's with a controller, if you did you could have from 0-100% element power control and heat. There has been postings of a control system using only a SSR on 240 volts breaking only one leg making the element become back fed and electrically hot thru the element back to the open SSR all the time from the other hot leg of 120 volts instead of using a SSRD and breaking both hot legs. I find this a wrong and a dangerous building practice not alone posting it on this forum. No nember name mentioned, WTF do I know? I've been mentioning SSRD's for a couple years on this forum, seems expense to members or not going that way ending up with two SSR's per element (on 240 volt systems not 120 volt)instead of one SSRD. Same with a waterproof box with holes drilled with cords thru them instead of using a CGB's or cord grips. Silicone seems to be the answer on many installations also just as long as the brewery works.
This is my two cents worth.

No, I will not be using a contactor for all the reasons BrewBeemer mentions. If I can find an SSRD, I'll use it.

EDIT: DigiKey has some SSRD's in stock, but they're not cheap. Here's the catalog page.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=646-1030-ND

On a positive note unrelated to digital control...check out my fortuitous discovery:



I'll have an extremely efficient pro-brewery style custom exhaust hood for a fraction of the cost of a commercial unit!

Yuri, that is exactly what I have been researching for my own usage; i.e. using a toledo metal spinning cone as the base for my BK cone-chimney setup. What size cone is that (diameter)?

It's a 21 gallon hopper, measuring ~20" in diameter at the top. The kettle is a 20 gallon MegaPot from Northern Brewer.

BrewBeemer said:

CodeRange; the contactor is ok for isolation of power to your control panel but is useless if your using it for controlling the heating elements as the pulse on and off times would have that relay chattering to no end unless if a controller were used to automate your temperatures in your keggles. You would have to manually switch the contactors coil and this is about as cave man as you can get in brewing. You would not have any tempeterature control of your heating elements without the SSRD's with a controller, if you did you could have from 0-100% element power control and heat. There has been postings of a control system using only a SSR on 240 volts breaking only one leg making the element become back fed and electrically hot thru the element back to the open SSR all the time from the other hot leg of 120 volts instead of using a SSRD and breaking both hot legs. I find this a wrong and a dangerous building practice not alone posting it on this forum. No nember name mentioned, WTF do I know? I've been mentioning SSRD's for a couple years on this forum, seems expense to members or not going that way ending up with two SSR's per element (on 240 volt systems not 120 volt)instead of one SSRD. Same with a waterproof box with holes drilled with cords thru them instead of using a CGB's or cord grips. Silicone seems to be the answer on many installations also just as long as the brewery works.
This is my two cents worth.

Click to expand...

BrewBeemer.... Put the SSR in series with the contactor on one leg. I am very familiar with relay chatter.... I threw this guy out there because poeple have been suggesting relays which are not rated for this kind of current, which is dangerous. This way you can isolate both legs off the heating element with no back feeding when the HOA is in the Hand or Auto position. Two sets of Normally open contacts of the switch wired in parallel to energize the contactor and another NO contact on the Auto side to gate the PWM signal to the SSR and a NO on the Hand side to provide a constant on signal to the SSR. Hell, if you dont want a manual override, a 2 positon OA will work fine. In either case the system should be treated as energized if the switch is in position but off. If it were me I would put the contactor between the SSR and the element. A main disconnect of sorts. I trust mechanical isolation over solid state any day of the week....
Not to mention that these kind of contactors are used for motor controls all the time, they are designed to switch a load.
I have three aversions for SSRs. One you cant look at an SSR and KNOW that the contacts are open or closed. Second, EMF is enough to trigger an SSR to fire. Last, dealing with the heat generated across the triac junction must be handled. Using an SSR to PWM one leg of the 240v and a mechanical disconnect is hardly dangerous. You could use 2 SSRs or a double pole SSR instead but you have introduced a second point of failure.

We aren't all raging incompetents....

Damn Yuri, do you buy those conical hoppers from TMS in bulk? Here's an idea...get yourself a stainless heating element and mount it near the bottom of your conical fermenter. Then it can pull double duty as a BK One less vessel and one less transfer.

Use your jacketed cooling system to bring it down to pitching temps and drop the cold break out the dump valve. Course you'd only be able to do one batch at a time I suppose....okay so I haven't fully thought this one through. Then again, I'm only able to brew once a month at best.

I'd drop one in my stainless conical fermenter project and give it a go but I'm not ready to convert to electric on the BK quite yet.

Just in case there is any confusion as to what I am talking about. ignore the NO comments on the element. Copy and paste error.

Yuri_Rage said:

No, I will not be using a contactor for all the reasons BrewBeemer mentions. If I can find an SSRD, I'll use it.

EDIT: DigiKey has some SSRD's in stock, but they're not cheap. Here's the catalog page.



On a positive note unrelated to digital control...check out my fortuitous discovery:

I'll have an extremely efficient pro-brewery style custom exhaust hood for a fraction of the cost of a commercial unit!

Click to expand...

Yuri; Your A ConeHead, remember them years ago?

CodeRage; I hear ya and understand fully what your talking about and coming from and yes I full agree mechanical contactors are about as fail safe as you can get, a lot safer than a SSR / SSRD in knowing it's state alone outside noise that can cause false triggering it. Ouch those unprogramed functions could be a safety problem with anyone working around them.

Damn Yuri, that sure looks like you could be able to make a conical fermenter out of that pot and cone. Wheels spinning and thinking at this end.
Thanks for posting.