Double Batch Electric System

[cliffo]

Hi All,

We're about to move into our new house and I am starting to think about setting up a new all electric double batch brew rig.

What are people's opinion on the ideal watts required to provide a solid boil for a double batch brew (thinking around 42L into fermenter)?

I have had a 15amp circuit wired into the garage so I can run a 3600W element but am unsure if this is sufficient for a double batch.

I already have a 2400W immersion element that I can use in addition if needed but would that then provide too vigorous of a boil on top of a 3600W element for this size batch?

Yet another question, would 2x 2400W elements be a better option for this size batch?

Cheers,
cliffo

 

[QldKev]

I would go 2 x 2200 or 2400 elements

Then get one of those 240v 3600w dimmers to control the second element.

Then you have the power to get to the boil in a decent time and can wind it back once you are there.

QldKev

 

[iralosavic]

How would you arrange 2 stick elements in a keggle? I mean above/below is obvious, but if you BIAB like me, you end up with too much unusable depth for the grain bag to swim in. If insulation doesn't improve my power enough I might be in the same boat. Fingers crossed though - it's already enough of a challenge getting watertight seals on the 3 connections I have.

 

[Filby]

How would you arrange 2 stick elements in a keggle? I mean above/below is obvious, but if you BIAB like me, you end up with too much unusable depth for the grain bag to swim in. If insulation doesn't improve my power enough I might be in the same boat. Fingers crossed though - it's already enough of a challenge getting watertight seals on the 3 connections I have.

I run two 2200w elements in a 50lt keg for just doing single batches. Yer you lose room but I dont ramp temps with the bag in the kettle.


Fil

 

[iralosavic]

So you just allow the bag to droop over and around the element and taps? I'm building a false bottom to sit above them, regardless of whether or not I ever ran the elements while mashing - perhaps I should consider not using one?

Edit - so you run them above/below?

 

[pbrosnan]

I've got a 2.4 and 3.6Kw element in a 100l vessel. I plan to do 75l batches but because I've got to upgrade the tun I've only had it up to about 40l. With that volume it comes to a biol in about 15 minutes with both elements on.

 

[Cocko]

Hey Cliffo,

I have just finished my triple batch electric rig and tested it just today by doing a couple of double batches...

My Kettle is 98L, and I am running 3x 2400w elements. I have 3 phase power so is split between to run the 3, one phase each.

What I found today, running 2 elements for the boil for the double batch was spot on.

If you can I would go 2x 2400w rather than one 3200w....

2 reasons:

I don't think 3600w will do the job 'well' - By well meaning getting to a ****** boil could take for ever.

2. 2x 2400w gives you the option to do single batches of trial beers if you need to...

Just a 2c and no spin.

Cheers

 

[pbrosnan]

Hey Cliffo,

I have just finished my triple batch electric rig and tested it just today by doing a couple of double batches...

My Kettle is 98L, and I am running 3x 2400w elements. I have 3 phase power so is split between to run the 3, one phase each.

What I found today, running 2 elements for the boil for the double batch was spot on.

If you can I would go 2x 2400w rather than one 3200w....

2 reasons:

I don't think 3600w will do the job 'well' - By well meaning getting to a ****** boil could take for ever.

2. 2x 2400w gives you the option to do single batches of trial beers if you need to...

Just a 2c and no spin.

Cheers

If you've got 15A go 3.6

 

[Cocko]

If you've got 15A go 3.6

So 3600w element boils 50 odd litres? Does it do it well?

Cheers

 

[iralosavic]

So 3600w element boils 50 odd litres? Does it do it well?

Cheers

I think (based on a spreedsheet a forum member [forgot his ID] shared with me) that 3600w would be very borderline for 50L of wort. Assuming effective insulation of the walls and a reasonably narrow opening at the top, you'd be right, but without insulation and with a large (ie 30cm+) opening, you'd be struggling to maintain a boil once the lid was removed.

You lose around 1.4kw of effective power through a 30cm opening, for example. Even a 50 keg has a 40cm opening (unless you cut the top out smaller, of course), so most larger volume pots are going to have fairly large openings, costing you valuable watts.

 

[Online Brewing Supplies]

I think (based on a spreedsheet a forum member [forgot his ID] shared with me) that 3600w would be very borderline for 50L of wort. Assuming effective insulation of the walls and a reasonably narrow opening at the top, you'd be right, but without insulation and with a large (ie 30cm+) opening, you'd be struggling to maintain a boil once the lid was removed.

You lose around 1.4kw of effective power through a 30cm opening, for example. Even a 50 keg has a 40cm opening (unless you cut the top out smaller, of course), so most larger volume pots are going to have fairly large openings, costing you valuable watts.

Matho's spreadsheet is the one you mention. I use a 2.4 Kw element for 30-40L boils, takes a while to get there but once there its too much.
Nev

 

[Deebo]

Maybe different elements boil differently? I have 2400w in birko urn and that seems just about right for a 31-32 boil

 

[Cocko]

Matho's spreadsheet is the one you mention. I use a 2.4 Kw element for 30-40L boils, takes a while to get there but once there its too much.
Nev

So what is your final volume Nev? Actually, start volume too ?

 

[jyo]

So what is your final volume Nev? Actually, start volume too ?

Reported.





Is that the element in the keggle from the last brew day, Nev? I have to say it surprised me.

 

[Online Brewing Supplies]

So what is your final volume Nev? Actually, start volume too ?

I add 17% for boil (70-80 mins) off. So 30l batch is +17%.
Nev

 

[Cocko]

I add 17% for boil (70-80 mins) off. So 30l batch is +17%.
Nev

Sorry mate, not boil off rates..

I am asking what actual volume you can 'boil' with your 2400w element?

So, hence the final volume question, being about the evaporation rate/how well it boils....

Cheers

 

[iralosavic]

Maybe different elements boil differently? I have 2400w in birko urn and that seems just about right for a 31-32 boil

An urn has an element that has been either designed for or selected to suit the vessle, so it should be more efficient in that regard. Also, I reckon all my kettle needs is another 200-400w to maintain a rolling boil at 30-35L. It holds 96-98c without insulation. I'm hoping that Matho is on the money with his calculation that I'm losing 500w through the walls and that I can preserve at least half of that with some insulation.

I'd be nervous to base my design around a 3600w element if I were wanting to boil 50L. Given that a 3.6kw @240v = 15a, you'd be requiring a dedicated circuit (or a special arrangement whereby nothing else is running at the same time anyway, so you might as well find a way to run 2x2.2kw or 2x2.4kw and just put either one or both on a potentiater to moderate the boil once it gets there.

 

[Online Brewing Supplies]

Sorry mate, not boil off rates..

I am asking what actual volume you can 'boil' with your 2400w element?

So, hence the final volume question, being about the evaporation rate/how well it boils....

Cheers

Ok Then I boil 30L +17%, of course this goes down as evaporation takes affect.
Same answer = 30L brew length . I can do 40L but it wont fit in a 30L keg
Nev

 

[pbrosnan]

So 3600w element boils 50 odd litres? Does it do it well?

Cheers

A 3.6 plus a 2.4 does. The point is, if you've had a 15A outlet put in you might as well make use of it. P=VI.

 

[Filby]

So you just allow the bag to droop over and around the element and taps? I'm building a false bottom to sit above them, regardless of whether or not I ever ran the elements while mashing - perhaps I should consider not using one?

Edit - so you run them above/below?

Yerp one above the other..separated by about 30mm. Bag just sits on top of everything. There's no sharp edges so it doesnt really matter.