Oven control for brewpot?

[Marsdude]

Would an oven control from a range work to maintain a boil in an electric brew pot?

I know it would take the voltage and turn the element on and off at a certain temp but it would not pulse like a PID/SSR setup. What do you think would this work?

 

[Walker]

temperature based control of a boil kettle won't really work. The temp of boiling wort is the same regardless of whether you have a good boil or a crazy volcano. (Plus, I think oven controls have a pretty wide swing on the low and high temp points that cause the power to cycle.)

You need pulse-based power cycling to control a kettle properly. A PID with manual mode is one way to do it (the temperature input is not even USED in manual mode), or you can build a pulse width modulator for a few $'s if you're not afraid of soldering some electronics together.

 

[Cliff897]

Would an oven control from a range work to maintain a boil in an electric brew pot?

I know it would take the voltage and turn the element on and off at a certain temp but it would not pulse like a PID/SSR setup. What do you think would this work?

I have contemplated the same thing. IT makes sense that a range top controller would be very useful and they seem to be tough as nails. However I think I'd still wire it in line with a PID or a BCS.

The one question you'd need to answer is the one about load. What's the rated load for the range top controller? Answer that and you should be golden. Or on the flip side just try it: What's the worst that can happen?
The absolute worst is you'll kill it?

 

[cyberbackpacker]

Search for tdiowa on here; he did this with great success, and even compiled a nice document detailing everything and how to do it.

EDIT: Go here: https://www.homebrewtalk.com/f51/electric-kettle-instructions-100737/

 

[Marsdude]

Search for tdiowa on here; he did this with great success, and even compiled a nice document detailing everything and how to do it.

EDIT: Go here: https://www.homebrewtalk.com/f51/electric-kettle-instructions-100737/

Thanks for the info. Great information. I wonder if a normal oven control would do the same thing as the Simmerstat he uses?

 

[cyberbackpacker]

Yes, it will. The simmerstat is an infinite switch, and that is exactly what an oven/range control is, an infinite switch. I believe the name simmerstat is just used for it in different parts of the world (UK and australia from my research). You can pick up a 15 amp (good for 3000 watts) oven/range infinite switch for about $15 and be good to go.

Good luck.

 

[Walker]

How long of a lifetime do these things have? Seems like a good option if they can hold up to the test of time.

 

[Marsdude]

Yes, it will. The simmerstat is an infinite switch, and that is exactly what an oven/range control is, an infinite switch. I believe the name simmerstat is just used for it in different parts of the world (UK and australia from my research). You can pick up a 15 amp (good for 3000 watts) oven/range infinite switch for about $15 and be good to go.

Good luck.

Thanks. I was thinking of taking one off of an old range I have in the shop.

So, would I be better off if I used the oven control with a it's thermocouple inserted into a copper thermal-well I would install on the pot - or should I just use one of the range's element controls? I was thinking I could set the oven control to somewhere around the boiling point and leave it be.

 

[cyberbackpacker]

walker My mother has lived in the same house for over thirty years with the same stove, and she has never had to replace a control (or anything for that matter). So I am thinking they are pretty robust.

marsdude: I personally would just go with the range control; that way you can set it to "max" and then back it down once it is boiling if it is too vigorous.

 

[Walker]

Maybe I am wrong, but.... I'm pretty sure you don't want anything that needs feedback from a temperature probe.

It looks to me like those infiinte switches effectively act like pulse generators, but rather than really being based on time, they are based on the heat generated by electricity passing through them. They don't care at all about the temp of what's in your kettle.

However, the controller for an oven is probably based on an actual thermostat. I don't think you want one for an oven, but one for a range-top instead.

 

[Walker]

walker My mother has lived in the same house for over thirty years with the same stove, and she has never had to replace a control (or anything for that matter). So I am thinking they are pretty robust.

Cool. This is nice, compact, off-the-shelf solution then.

Some folks use PIDs with manual mode, but that is pretty wasteful for a kettle since you don't need temp feedback, which is really what the PID is all about. A PID that will only be used in manual mode is a waste of $, IMO.

I built a small pulse width modulator to control my kettle. That's cheaper than the PID or infinite switch, but I had to spend the time to assemble it. This switch seems pretty damn handy.

EDIT: I guess I should actually look to see if they make them burly enough for my kettle... I am driving a 5500W element, so I need more than 23A@240V. That might change my opinion on the price effectiveness.

 

[cyberbackpacker]

I agree with your assessments. I think for people doing up to 5 gallon batches, this is a very inexpensive and simple solution to electric boiling.

 

[Marsdude]

Walker, I think you're right and I will stick with the range element control.

 

[Walker]

I agree with your assessments. I think for people doing up to 5 gallon batches, this is a very inexpensive and simple solution to electric boiling.

Absolutely! You don't need solid state relays or anything.

I think you have just made my day here (assuming I can find one for 25A or more at a good price). My system is starting off with a single electric element, sometimes controlled by PID for temp management, sometimes controlled by my DIY pulse modulator for boil control.

I will eventually upgrade and add a dedicated electric heat exchanger for the mashing, which would require me to buy another SSR and heatsink at some point in the future. That's been my plan. But, if I can get an infinite switch that can handle 25A, I wouldn't need another relay and could retire the modulator I built at that time. (PID controls relay controls exchanger, and new infinite switch controls kettle).

 

[Walker]

on the other hand..... I already have the modulator, and I doubt I would be able to find an infinite switch for less than $16 (the price of another SSR+heatsink), so maybe this ISN'T something useful for me personally, but it's a damn good idea anyway!

 

[cyberbackpacker]

Walker, I looked into these infinite switches in quite detail back when tdiowa first posted on his setup, but never came across anything greater than 15a (and that included internationally too). However, that is not to say they are not out there, just that I did not find them.

 

[Marsdude]

Walker, I looked into these infinite switches in quite detail back when tdiowa first posted on his setup, but never came across anything greater than 15a (and that included internationally too). However, that is not to say they are not out there, just that I did not find them.

What little research I have done seems to indicate that the switches are 15a which gives you 3,600 watts with 240V. What wattage do you need in an element to boil 6.5 gal of water in a reasonable time?

 

[wilserbrewer]

What little research I have done seems to indicate that the switches are 15a which gives you 3,600 watts with 240V. What wattage do you need in an element to boil 6.5 gal of water in a reasonable time?

3600 watts would bring 6.5 gal to a boil in a reasonable amount of time IMO...at least as fast, or faster than most any external burner I would imagine.

 

[Walker]

I'm growing impatient as I age. I want water to heat up ASAP.

But more than that, I want to be able to do 10 gallon batches from so I'm using 5500W.

 

[Walker]

3600 watts would bring 6.5 gal to a boil in a reasonable amount of time IMO...at least as fast, or faster than most any external burner I would imagine.

It won't be as fast as a propane burner, but it would probably be tolerable.

I've got a spreadsheet on my computer that calculates times for electric heating, but I'm on my phone now and highly unmotivated to go get the laptop and fire it up.

 

[Marsdude]

Thanks for the info.

What I am thinking of doing is installing the element in an old steam jacketed kettle that I picked up at an auction for $5 years ago. It looks something like this:

http://cgi.ebay.com/40-Gallon-Jacketed-Tilt-Steam-Kettle-with-Faucet_W0QQitemZ250563679210QQcmdZViewItemQQptZBI_Steam_Cooking_Warming?hash=item3a56c253ea

I think it will hold 20 gal but I would only be doing a 5 - 6.5 gal boil. The bottom part of the kettle is double walled and I am hoping that will provide a little insulation, because of the dead air space, making it a little easier to reach boiling temps.

 

[Walker]

It won't be as fast as a propane burner, but it would probably be tolerable.

I've got a spreadsheet on my computer that calculates times for electric heating, but I'm on my phone now and highly unmotivated to go get the laptop and fire it up.

I pulled open the spreadsheet. I've never seen a 3600W element before, but I have seen 3500W ones, so these numbers are based on 3500W.

A few data points:

• To heat 4 gallons of water from 65*F to 170*F (a rough example for heating strike water for an AG batch) it would take 18 minutes.
• To heat 3.5 gallons of water from 65*F to 170*F (rough example for sparge water) would take 15 minutes.
• To heat 6.5 gallons of water from 65*F to 212*F (rough example for full-boil extract), it will take about 40 minutes.

NOTE: these numbers assume a perfectly insulated kettle with no heat being lost to the environment (something that doesn't exist) so these numbers are pretty optimistic and actual heating times would be greater in practice.

As a final data point: when I bought my ultra cheap-o turkey fryer burner I did a test to see how long it took to heat 5 gallons of cold tap water to a boil. I measured 18 minutes. That's real world time including heat loss from a non-insulated keggle. The 3500W element in an ideal situation would take 31 minutes for that task.

So, 3500W is probably half as fast as heating with a cheap-o turkey fryer burner, but doesn't seem ridiculously long.

Of coutse, I have no idea how much heat you will actually lose to the environment, but in the long "heatstick" thread, people claim to be able to get a good boil relatively fast with 4000W, so.....

 

[Marsdude]

Thanks for all the data Walker. I can live with those numbers. Also, although I've never brewed all grain, I am guessing that after the strike and sparge your wort is around 140 -150??? So it would be quicker to bring it up to a boil that starting from 65 degrees.

 

[Walker]

Thanks for all the data Walker. I can live with those numbers. Also, although I've never brewed all grain, I am guessing that after the strike and sparge your wort is around 140 -150??? So it would be quicker to bring it up to a boil that starting from 65 degrees.

The runnings in the kettle should be well above 150*F. The mash-out water will have raised the temp of the first runnings above your mash temp, and then you sparge with water that is well above mash temps, too, so what is in the kettle at the end of it all should be about 170*F.

Getting 6.5 gallons of 170*F wort to boiling with 3500W will (in an ideal system) take only about 11 minutes.

Edit: note that you can start heating up the first runnings as soon as they are in the kettle, so that 11 minutes is actually overlapping with time you are doing the the sparge and collecting second runnings. You wouldn't be waiting around very long for it to start boiling after all the runnings are in the kettle.

 

[Walker]

What I am thinking of doing is installing the element in an old steam jacketed kettle that I picked up at an auction for $5 years ago. It looks something like this:

http://cgi.ebay.com/40-Gallon-Jacketed-Tilt-Steam-Kettle-with-Faucet_W0QQitemZ250563679210QQcmdZViewItemQQptZBI_Steam_Cooking_Warming?hash=item3a56c253ea

I think it will hold 20 gal but I would only be doing a 5 - 6.5 gal boil. The bottom part of the kettle is double walled and I am hoping that will provide a little insulation, because of the dead air space, making it a little easier to reach boiling temps.

I actually missed this post amidst the discussion of the infiinte switches.

Marsdude.... that thing f*cking kicks a*s! I'm jealous.

 

[Walker]

Hmmmmm....

I know that link to ebay is not your exact kettle, but if yours is shaped like that, you *might* have a little bit of an issue to deal with. The whole bottom of the thing is dome shaped. If you install the element above the point of the curvature, it might be too high up on the thing to actually be submerged in 5 gallons of liquid.

If you install it on the curved portion, the element might be long enough that it pokes through the surface of the 5 gallons of liquid.

The element has to be 100% submerged in the liquid or it'll burn up.

I don't want to poo-poo on your parade, but make sure you check things out before you start cutting steel!

 

[Marsdude]

Hmmmmm....

I know that link to ebay is not your exact kettle, but if yours is shaped like that, you *might* have a little bit of an issue to deal with. The whole bottom of the thing is dome shaped. If you install the element above the point of the curvature, it might be too high up on the thing to actually be submerged in 5 gallons of liquid.

If you install it on the curved portion, the element might be long enough that it pokes through the surface of the 5 gallons of liquid.

The element has to be 100% submerged in the liquid or it'll burn up.

I don't want to poo-poo on your parade, but make sure you check things out before you start cutting steel!

I actually woke up this morning thinking about this. You have a good point. I think I will be able to mount an element in this but I have to see how high 5 gal goes in the thing, measure an element, etc, before I start drilling through the side.

I also have an issue with the bottom of the pot being double walled in addition to being curved. My hope is that I can drill a hole that will allow me to weld a female threaded SS coupling into it that would allow the element to be horizontally level and as close to the bottom as possible.

Right now the kettle is under about a foot of snow behind the old shop up here so I will have to wait a while to fool around with it.

 

[Walker]

I think I will be able to mount an element in this but I have to see how high 5 gal goes in the thing, measure an element, etc, before I start drilling through the side.

Keep in mind that elements come in various watt densities. You can get the same wattage element in (for example) high watt density and ultra low watt density.

The high watt density ones will be much smaller. Those might have the size you need, but high watt density is something you probably want to avoid. You want the watts spread out on the element so that you don't scorch the wort.

Good luck! I hope it works out.