Electric Kettle

[kirem]

I fired up the electric kettle yesterday. Very strange watching wort boiling away with no more than the splashing sound of the wort.

Silent brewing, brings back another career! run deep, run silent!

It worked very well, I didn't time it but it was significantly quicker than my gas version. The PID temp controller worked very well, keeping the boil vigorous without having the element running flatout.

The difficult part is setting a temp. The wort will only boil at its natural boiling temperature, I can't set 100 degC and it gets there. It basically puts all its power into the boil and will never go over what is natural without the use of pressure.

So what temp do I set? Is it going to be different every time? Is there some magic formula that says the wort is this much sugar, this much water and it should boil at this temp?

Yesterday despite how much power (upto 3.6kW) was applied the wort didn't get above 96.8degC, the wort was boiling vigorously and that is what I aimed for with the gas burner.

So anyone out there that can offer some technical details?

It was great not having to worry about everything around the kettle being heated up as well, probably first brew day I haven't burnt myself.

 

[lou]

I have an electric kettle but don't have a PID

I have 2 kettle elements inthe boiler. sometimes I use 1, sometimes both

I also have a 'stove' controller that can be attached to either element - technically its called an 'infinite control' or simmerstat

but its just a mechanically timed on/off device.

I find that i don't get boil overs and can boil with 1 or both elements on - which is not at all what I expected when I built it

I thought I would have all sorts of problems controlling the boil - not so as it turns out

the only difference between having 1 or 2 elements on is the speed it all comes to the boil (which is very useful)

and a change in the evaporation rate - Have two elements on does make the boil very vigorous however.

I think the elements are both around 2000W

I am not sure that a temp gauge for boiling would work very well - the difference in temp between a rolling boil which is what you want and a boil over would a be a fraction of a degree and it would change depending on the density of the wort. (which changes over he course of the boil

The only way to do what you want is to use one of those pulse controllers which really do give you control over the power input
these are expensive and I am not sure if they are available in australia

lou

 

[The King of Spain]

Can I ask how much I could expect to spend on and electric set up? Where do you source your components?

The way LPG is going its not going to be long before the bottles cost less than the gas.

Cheers

 

[Jazzafish]

Can I ask how much I could expect to spend on and electric set up? Where do you source your components?

The way LPG is going its not going to be long before the bottles cost less than the gas.

Cheers

You can spend as much as you want on elements. Some people buy cheap kettles from the supermarket and pull them apart ~ $20 - $30. Some people buy hand held elements from brew shops ~ $100 - $150. I have also heard of people using elements from dish washers and hot water systems. Can't gustimate the costs here.

One thing that you need to consider with an electric kettle is the running cost. Plug one in and go have a look at your electricity meter... serious RPM!

I run an electric HLT, gass kettle. I dare say gas is cheaper to run. I also have my element hooked up to a thermostat for convienience. You could do that with gass too, but it can be a bit more tricky to set up.

 

[Adamt]

I think you'll find it will be difficult to get a definitive accurate numerical answer based on smallish fluctuations in SG, as the boiling point increase could be quite small (of the same order as atmospheric pressure effects on boiling point).

Maybe take some data from each brew you do (with different SGs) and use that to predict future boils. 96.8C sounds a little low so maybe your temperature probe is out?

 

[Hargie]

....i boil 48ltr batches in an electric wash copper with an additional 2400w immersion element...total 4800watts....boiling temp of 99.6...

...canberra is about 600m above sea level....

 

[Zizzle]

I don't think electric would cost more than gas. I run 2 2kw elements for about 2 hours to do a brew. I think we pay about 16c per kw/hr here.

i.e. 2 * 2 * 2 * 0.16 = $1.28 for a brew.

And most setups heat and boil with less than 4kw so they would probably average less than a dollar per brew. It would be pretty hard for gas to beat that. You probably spend more than that driving down to the servo to swap a bottle.

 

[Thirsty Boy]

Kirk,

I know its an obvious one but; have you calibrated the PID?? Is it reading 100C in water thats boiling nice and hard? It might just need to be put up or down a degree or two.

I dont really think that a temp gauge is the right tool for controlling the vigor of a boil. After all, you can have 110C water thats not boiling and 100C water that is boiling... how is a temp probe meant to tell the difference? you need something more like a simmer stat that cycles on and off and you just tweak it manually to get the boil level you want. Maybe you can set the PID up to do it? But I dont know if they do that stuff.

Or perhaps just a separate control unit that manually adjusts the voltage/power/whatever to the element. Set it to one for a gentle simmer and to ten to have the wort jumping around

I use a PID on my HLT and its great for holding the temp at a set level, but I cant imagine how I would set it up to hold a boil at a certain level of vigor

Dont think I've been very helpful, sorry

Thirsty

 

[user 1153]

serious RPM!

Yeah but still nowhere near the exorbitant cost of gas. really LPG shouldn't cost as much as it does.
A friend of mine worked it out and electricity costs him about $2.40 per brew.

Edit: missed Zizzle's post. I was way off maybe he said $1.40 per brew.. Either way electricity is much cheaper than gas.

 

[Enerjex]

slightly off topic but the question registered with me, do you have problems with the wort burning onto the elements?

 

[Sammus]

Can I ask if your actually using a PID for your boil? the term PID controller gets thrown around a lot, nearly everyone Ive spoken to (except those on the coffeesnobs forums) is actually using a digital thermostat. I think it would be very unnecessary to have one to control your kettle for a few reasons: the mass of water means the temperature is going to be increasing pretty slowly, so theres basically zero risk of overshoot; overshoot is impossible anyway since the temperature is going to be the same no matter how vigorous the boil is; and as a result of that last point, you can't measure the vigorousness of a boil with temperature of the liquid anyway.

I think if you want a less vigorous boil you will need either a secondary much less powerful element that you use by itself once your up to boil, or some kind of device that will limit the power available to the element (probably a pretty pricey piece of electrogadgetry). Or get a digital thermostat set to 100C with a 1C differential - then you will get a kind of pulsing boil, probably not the best option. Id go for a low power secondary element. (maybe 850W or something)

 

[MHB]

I have always used 102 C as the boiling point for wort, but kirem post sent me looking through some of my books.
The main factor appears to be the depth of the wort; starts to make a noticeable difference once your wort depth get over a couple of meters; hardly something that I or any other home brewer I know needs to worry about.

The text books use the rate of evaporation (how much steam is coming out the top) to measure the vigour of the boil - so all we need is an enclosed kettle, a flowmeter in the chimney ..narr it's all too hard.

If you check with a local electrical wholesaler you should be able to get an element for an urn. The older ones that had "Low - Medium - High" are ones to go for, what they are, is a 1200W and a 2400W element on a common mounting post.
Low is just the 1200W Medium is the 2400W and High is both at once.

Thats for a 3600 W Urn; there are 2400W configurations available to (800W, 1600W, 2400W) if you dont have the juice for a 3600W.

Same supplier could sell you the 4 position rotary switch.

MHB

 

[kirem]

I use a 'pulse controller' on my water purifier. It is a burst fire controller from the UK - sutronics. It does the same thing to the voltage that the PID essentially does, chops it up so it looks like a lower voltage/power is applied to the element.

the PID controller has some smarts behind it the sutronics controller has me to turn the pot thus power down.

I think after this 'experiment' I will get another sutronics controller for the kettle.

I did calibrate the temperature probe, but I am still a little suspect of it. I am taking into work to test it against some thermometers in the lab.

No I didn't have any scorching issues

Yes they are PID controllers and I have had very real overshoot problems using a basic temperature controller on my HLT/heat exchanger

 

[lou]

The wort doesn't burn onto the elements

the one little problem though is that you get protein coating the elements. Not a problem for 1 or 2 boils but after this the protein starts insulating the element from the water and overheats the element.

I have found that my elements need constant cleaning

So its not the wort burning you need to worry about but rather the element burning out.

I do believe that the effect is slightly different from underfiring a kettle - I believe but cannot prove that the caramelisation/darkening/melanoidan reactions are different in an electric kettle



lou

 

[ArnieW]

So what temp do I set? Is it going to be different every time? Is there some magic formula that says the wort is this much sugar, this much water and it should boil at this temp?

Hi Kirem,

I don't know if your PID will allow you to do this, but I simply set a target that is unreachable (102 degC) and then vary the % power applied to suit a rolling boil. My system will typically run at 100% power below 97 deg, and then slowly winds back the power to about 60% for a nice rolling boil. I personally think that a PID controller is wasted for boiling. I don't use one on my HLT either but it is the bees knees for my heat chamber which controls the mash temperature.

Check out Brewing in the sunshine for a pretty graph that shows the HLT oscillating around its set point and a mash that is nicely regulated with PID.

cheers, Arnie

 

[kirem]

Hi Arnie,

Yeah, I think that a PID controller is not the correct option for a kettle. My HLT is my heat exchanger as well, although I am thinking of building a dedicated heat exchanger and leave the HLT as a HLT. PID control works very well for both these applications. I don't want overshoot/undershoot on either of these.

I use one of these on another similar application and just purchased another for my kettle. Free shipping atm

http://www.sutronics.com/acatalog/Burst_fi...ontrollers.html

View attachment 14026

and yes I will put proper connectors on those wires....eventually.

 

[ArnieW]

Hi Arnie,

Yeah, I think that a PID controller is not the correct option for a kettle. My HLT is my heat exchanger as well, although I am thinking of building a dedicated heat exchanger and leave the HLT as a HLT. PID control works very well for both these applications. I don't want overshoot/undershoot on either of these.

I use one of these on another similar application and just purchased another for my kettle. Free shipping atm

http://www.sutronics.com/acatalog/Burst_fi...ontrollers.html

That burst controller looks like it will do the job nicely. PID is definitely the way to go on a HLT that doubles as a heat exchanger - but if you are interested I have a ready built heat chamber (direct heating) that is now surplus to requirements. It has a 3000W element in it. Not sure about price as yet - but the copper fittings were suprisingly expensive :blink:

 

[Tony]

Hi Arnie,

Yeah, I think that a PID controller is not the correct option for a kettle. My HLT is my heat exchanger as well, although I am thinking of building a dedicated heat exchanger and leave the HLT as a HLT. PID control works very well for both these applications. I don't want overshoot/undershoot on either of these.

I use one of these on another similar application and just purchased another for my kettle. Free shipping atm

http://www.sutronics.com/acatalog/Burst_fi...ontrollers.html

View attachment 14026

and yes I will put proper connectors on those wires....eventually.

Just bought one too for a similar application to kirems similar application

WHat are you boys using to chop the power to the elements in the HLT with the PID control? have you got a unit like these with 4-20mA input instead of the POT?

cheers

 

[ArnieW]

Just bought one too for a similar application to kirems similar application

WHat are you boys using to chop the power to the elements in the HLT with the PID control? have you got a unit like these with 4-20mA input instead of the POT?

cheers

Hi Tony, I'm using a picaxe microcontroller that pulses a duty cycle between 0 & 100% to a solid state relay.

Kirem, if you want to know more about the heat chamber, there is a blog on the build session here

 

[kirem]

Tony,
Similar to Arnie. My PID controller outputs a logic level 0-5vDC that switches a SSR. I don't have a solution for a current driven application.

Arnie,
I had a look at your heat chamber, seems like a RIMS vessel, is this correct? Does the element directly heat the wort passing through the chamber?