Rolling boil

[pips78]

Hey all
I have a question. I have been building my BIAB for the last 5 years and finally got to do a water brew tonight to flush out all the niggly bits and pieces. It’s a 70L SS vessel with 2 x 2200W elements in

it and I can’t get a good rolling boil on it like I have on bigger kit I’ve used. Do you think I have enough power there to do the job. It’s up around the 100deg C Mark but not rolling. They are the weldless elements kicking around. Any advice would be appreciated. Cheers Chris
Ps I’ve still got a few things to finish on it. Nearly there

 

[husky]

Ooohh nice shiny stainless! What was that from before you re purposed it?
Assuming your start of boil vol is 50L or so in the 70L tank, 4400W is on the light side I rekon. From memory I use approx. 3800W to boil 30L getting 10% evaporation and it's a visibly good boil. I would test your evaporation rate before making any changes. I always worked on 10-15% boil off per hour but I know micros who operate on 3 - 6% so you are likely ok.
It's hard with the gusset mounting plates but try wrap the tank in some insulation to reduce losses and improve the boil off a bit.
Love a custom build!

 

[unwrittenlaw]

Awesome looking build mate, well done..

Have you got insulation for it? Probably the cheapest upgrade I'd say. I got some clark rubber formshield last week for my 50L keggle, put it silver side inward.. boil is a bit better but still not very vigorous tho..2200w KK with 27l preboil vol.

Maiden brew I had a cheapo kmart camping mat that melted and I had to take off while the boil was ramping up.

Other suggestions, might sound silly, but were both elements firing? (One wasn't tripped?). And how much volume was in it?

All else failing, perhaps an ots immersion element? I hope you've got decent electrical circuitry.

does h2o boil differently to wort? My guess would be yes.

 

[Danscraftbeer]

Drawn and staring at that piece of equipment. Awesome although I would have gone a different way. Gas!
To turn yours up it needs more elements? and or more electricity juice. Is that really what it takes to boil 70lt? That seems like a lot of electricity. You have to plug into different sources from your house or trip your breakers etc. There's no way of conversion, getting a burner ring under there is there? Although combination seems too complicated.
I'm gas burner by preference, cant beat it really turn it up, down no worries etc.
I boil 55lt Keggle with plenty to spare with a simple beginners star burner thing from KK.

 

[pips78]

Thanks for the advice. The power thing is all good as Im an electrician and have installed a dedicated circuit for the system. I’ve worked in breweries before and the tank was a tetrahops tank but kept clogging up due to it being in a cold room. Still has the smell of hops after 7 years. I will try Getting some lagging for the outside as a start. I’m not sure how much volume exactly as that the next job of making a measuring stick to immerse in the tank. The gas option is not possible with the valves at the bottom of the tank, though it would have been a more efficient option.

 

[Matplat]

I use 2400w for boiling single batches, approx 30l preboil. The boil isn't very vigorous, but the beer still tastes good!

 

[husky]

Thanks for the advice. The power thing is all good as Im an electrician and have installed a dedicated circuit for the system. I’ve worked in breweries before and the tank was a tetrahops tank but kept clogging up due to it being in a cold room. Still has the smell of hops after 7 years. I will try Getting some lagging for the outside as a start. I’m not sure how much volume exactly as that the next job of making a measuring stick to immerse in the tank. The gas option is not possible with the valves at the bottom of the tank, though it would have been a more efficient option.

Electric is great for these smaller batches. My 20L 1V has 5kw that I can vary from 0-100% and if you are a sparky I would suggest more power then play around with volumes and boil off rate. The bigger power allows a good ramp rate then back off to the boil vigour that you want. As you say electric allows a coned bottom and valves in the base which I really do miss on my 200L 3V that runs a gas kettle.

 

[wobbly]

Unless your support feet are "insulated" from the frame you will also be conducting heat away from the kettle when trying to boil

Wobbly

 

[RobB]

As others have already mentioned, insulation can make a big difference. Try your water test again with some old towels or blankets wrapped around the kettle and see how you go. From there you can use something a bit sexier. I just use a $5 camping mat from Target because it's cheap and easy to cut to shape. Even at the end of the boil, the outside of my insulation is barely warm.

You can also try having the lid half on, although your lid looks pretty hefty so I don't know how you would go. Another trick is to float a stainless bowl on top of your wort (just a cheap one from an Asian grocer or even Ikea) which has a similar effect to having the lid half on - it will keep some of the heat in while still allowing plenty of evaporation. I think the 50 litre Braumeister has a 3.5kW element, so your 4.4kW should be enough.

It might also be helpful to note that a rolling boil doesn't have to look like an erupting volcano. A gentle boil is still hot enough, turbulent enough and gives enough evaporation.

 

[pips78]

Unless your support feet are "insulated" from the frame you will also be conducting heat away from the kettle when trying to boil

Wobbly

There is insulation between the vessel and the stand

 

[pips78]

As others have already mentioned, insulation can make a big difference. Try your water test again with some old towels or blankets wrapped around the kettle and see how you go. From there you can use something a bit sexier. I just use a $5 camping mat from Target because it's cheap and easy to cut to shape. Even at the end of the boil, the outside of my insulation is barely warm.

You can also try having the lid half on, although your lid looks pretty hefty so I don't know how you would go. Another trick is to float a stainless bowl on top of your wort (just a cheap one from an Asian grocer or even Ikea) which has a similar effect to having the lid half on - it will keep some of the heat in while still allowing plenty of evaporation. I think the 50 litre Braumeister has a 3.5kW element, so your 4.4kW should be enough.

It might also be helpful to note that a rolling boil doesn't have to look like an erupting volcano. A gentle boil is still hot enough, turbulent enough and gives enough evaporation.

The lid is on a hinge with a seal a small outlet for condensate. Maybe I’m over worried about how much it’s boiling but by the sound of it insulation is a must

 

[pips78]

I have put some blankets around and finally got a good rolling boil but it has taken about 35min from about 65deg to boil. I was not getting very good evaporation but with the lid off there is heaps more condensationView attachment 108811

 

[husky]

35 mins sounds ok but need to know your volume. Looks only half full if that so when you do full volume might blow out to 1hr +
Run the boil at normal volume for 30 mins and measure your boil off rate is what I would be doing.
Are you sitting a bag of grain in there? Are you lifting to ramp temps?

 

[MitchD]

You said you were an electrician, have you measured the resistance of each element? My 5500w only measured out at 4500w when I tested it.

 

[koshari]

You said you were an electrician, have you measured the resistance of each element? My 5500w only measured out at 4500w when I tested it.

elements are generally measured in ohms and rated in watts, and the resistance can change with temperature so the nominal power rating can take that into account.


regardless that is a lot of mass your heating and a lot of surface area to dissapate heat, previous suggestions of insulation are sensible.

 

[MitchD]

elements are generally measured in ohms and rated in watts, and the resistance can change with temperature so the nominal power rating can take that into account.


regardless that is a lot of mass your heating and a lot of surface area to dissapate heat, previous suggestions of insulation are sensible.

The OP is an electrician, as am I. The point, which you missed was that just because an element says its 5500w @240v doesn't mean it actually is. If he has capacity (amps, derr) but under performing elements I know what I'd be doing.

 

[koshari]

cheers mate, no i never missed that point which is why i made the comment about "nominal power rating", the op has 2x2.2kw elements, and he stated they are on a dedicated circuit which could assume they are paralleled on a 4mm2 dedicated circuit however he may have used 6mm2? If he has indeed used 4mm2 there would be more voltage drop at the elements assuming the cable run was the same distance than using 2 different circuits wired in 2.5 (assuming no other load on said circuits).

given your a sparky as well as the op and myself you would be well aware of a little bit of voltage drops effect on the final power dissipation on the element(s) given P = V^2 /R.

again i still agree with others comments that insulating the tun is the best course of action as every joule of energy saved from not radiating from the wall of the vessel will be used in latent energy from the boil.

 

[pips78]

35 mins sounds ok but need to know your volume. Looks only half full if that so when you do full volume might blow out to 1hr +
Run the boil at normal volume for 30 mins and measure your boil off rate is what I would be doing.
Are you sitting a bag of grain in there? Are you lifting to ramp temps?

Sorry that’s and old photo. Not sure how that made it in there

 

[pips78]

I ended up getting a good rolling boil after about 35min and the evaporation got up when I took the lid off. What’s sort of time after mash should it take to get up to rolling boil? And when do you start your timing of the boil from? If you get what I mean. I did a proper measurement of the L in the vessels and I was trying to get the boil on about 70L. Maybe too much. Probably more thank I need if I plan on sterilizing the line by filling a 20L cube and then fermenting 20L for a keg

 

[pips78]

Just thinking about the insulation. It should help a bit, but the tank is made out of 5mm thick stainless. That has a huge thermal mass. I boiled it on Saturday night and it was still hot Sunday morning with no insulation on.