IC cooling - recirculation or not?

[Kev888]

Hi all,

In a recent thread about bending microbore I managed to make a couple of longish narrow coils for my new IC - which will be used to cool up to about 100L and yet fit through a 6" hole in my new boiler.


But the question has moved on a bit now so thought I'd start a new thread. Basically I have these two compact coils (one will be inside the other) and I have to decide between stretching them out to allow wort to convect between the loops (possibly with an electrical stirer or something) or to leave them compacted as they are and recirculate wort between the two tubes that the coils form (once the wort has cooled enough for a totton pump anyway).

Whilst I've used ICs for years, I've not recirculated into one to aid cooling before, so find it difficult to gauge how much difference in cooling that its likely to have over the traditional open coil + stiring approach. I'm imagining they'd be similar, but does anyone know otherwise?

Cheers
kev

[boingy]

Probably not much difference assuming you stir pretty much continuously but that would be a bit of a drag so in reality recirc would be quicker but obviously at the extra expense and hassle of plumbing in some extra stuff.

It's just about how far you want to go. A static IC that is stirred round a few times works well enough for me, especially given that I chuck in some hops during the cooling. Faster cooling would not really save me any time because I would still want the hops to steep for 15-20 minutes. Is my system perfect? No. Is it good enough? Yes.

[Kev888]

Excellent, many thanks. Thats largely what I was hoping actually. I like the simplicity of the plain IC and the fact that there are no opaque tubes through which the wort passes, and they've always served me well in the past.

Perhaps I'll stretch the coils out a bit and if I later feel the need for extra speed just introduce a mechanical stirrer or some way of jiggling the coil itself up and down . I posted a thread some time ago about the speed of cooling and the verdict seemed to be that it wasn't especially important, I just wanted to check in case I was missing a no-brainer with the recirculatory option.

Cheers
kev

[bosium]

To echo some of what Boingy said, I think you certainly don't need recirculation if you're willing to stir the wort while it's chilling, but if you want to just leave it to do its thing then recirculation really helps as it keeps the wort constantly moving over the coils. I prefer to recirculate, so I can cover my kettle with clingwrap and turn the pump on and basically walk away until it's done - this way I don't have to worry about anything falling into my wort while it's chilling (I brew in my kitchen and I'm a little paranoid about contamination). I used to do the stir and chill method and it really works though.

If you don't stir in some way, the wort in close contact with the coils will chill but the rest of the wort will stay hot, thereby decreasing the temperature gradient between wort and chiller coils and greatly decreasing the cooling efficiency. Sure, there is some convection in the kettle but not that much. Just try putting your chiller in some boiling water and pumping some cold water through it. At first the water coming out will be boiling hot, but soon it'll be just luke warm even though the water in the pot is still very hot. Give it a stir, however, while feeling the temperature of the output water and you'll notice a definite increase in temperature.

If you're trying to do the Jamil Z thing of whirlpooling, just be aware that it doesn't work (in my experience) with whole flowers - he's talking about pellets which form a loose trub and are more likely to turn into a cone than flowers are. This action is further hampered by having things like elements in your kettle which disrupt the circular flow. I think you'd really need a gas-fired kettle and pellet hops to get it to work. I use a march pump to recirculate and whole hops and while I don't get much of a whirlpool effect at all, it does clear the wort by creating a filter from the hops compacting around my hop strainer and the action of constantly moving the wort in the kettle means it chills considerably faster.

[Kev888]

Thanks for that. Yeah I understand the difference between natural convection and moving the wort, just wasn't sure if recirculating was a much better way than stirring or not. I guess the answer so far is that moving the wort around is the key thing to speed cooling up - how its done is rather less important.

I wasn't going to try whirlpooling though, I can see recirculating would be very useful for that. I only use pellets occasionally and even then its in addition to flowers, but also my boiler setup (with the strainer and non-concentric access hole) isn't really conducive to the cone forming nicely either.

Thanks again,
Kev

[crookedeyeboy]

Whats the general feeling about sanitising if recirculating? Im assuming that everyone is working on the principle that if you use a pump to recirc that what goes through it first will be very hot so this will sanitise any hoses and pump etc?
Is this correct? Something Ive been wondering about doing.

[Kev888]

That was one of the things that prompted my thoughts actually - I've a totton pump rather than a march or something, so couldn't recirculate until the temperature dropped below 85c; so any jet/nozzle/piping part of the recirculation gubbins that wort passed through would have to be sanitised separately (apart from any bits below the level of boiling wort). So its getting away from some of the things I like about the humble IC really..

Cheers
Kev

[polymoog]

Kev, that is sterling work there on that cooler. I shall be building one myself very soon, how are you proposing to connect one coil to the other?

[Kev888]

Thanks for that - with the quality of your recent creations thats praise indeed!

After previous minor IC mistakes/regrets, this time the two coils are wound in opposing directions. I intend to point the ends of the two coils towards each other, put a 10-15mm fitting reducer (or I guess in this direction 'increaser') on them and join these together inside a 15mm tee; in the third leg of which will be some 15mm pipe heading up and out of the boiler.

That way I hope to keep it simple and yet maintain a minimum of 15mm or 2x10mm throughout (never just 1x10mm) - as I may want to use a small pump rather than high/mains pressure to circulate the cooling water in the future. Or at least thats the plan - the reality has yet to try and bite me. I did consider having the flow in opposite directions (top to bottom vs bottom to top) in the two coils, but I couldn't convince myself the extra pipe work was justified by the likely benefits in such a compact coil.

Another key decision I have with this particular design is that if I go with recirculating between the coils then the 15mm pipes would be put inside the inner coil to leave a clear path for recirculating between them. But if I decide to open out the 'springs' I'll want the 15mm pipes between the two coils so that a mechanical stirer or screw could later be put down through the inner coil. But probably if I had a wider neck to my boiler just putting them outside both coils would be the default.

Hope that makes sense - sorry it got a bit long-winded!

Cheers
kev

[Kev888]

I decided in the end to open out the coils a bit. I may dangle a silicone hose down inside the IC for recirculation type stirring or arrange something electrical to jiggle the IC up and down to create movement in the wort, but it should work reasonably well as is.

The connections between the coils aren't as I'd intended because the small diameter restricted what connection options would fit. Took a surprising amount of time to get everything pointing in the right direction and make the slightly flattened tube round enough for a connector - it had to be solder, no way compression or push fit would have dealt with the less than perfect tube shape, but it worked out well in the end:



I'll put a bend or elbow in the tails to and some of those brass hose connectors on the end like my last one and that'll be job done. Thanks for all the input everyone!

Cheers
Kev

[Kev888]

Just to add a full stop to this build, I finished the IC today. I bent a sort of brass 'C' shaped clip and soldered it to the two uprights, clamping them together, added the horizontal tails and tied the back of them together with some thick copper wire wound around and again soldered in place. The dead ends at the back are just to support the IC over the boiler:


And of course this is what it was all about - fitting into the boiler:

(The thing that looks like its connecting the brass connectors is actually the boiler's handle in the background)

I was thinking of curving the tails down the side of the boiler at some point to stop any drips from the hose connectors getting into the wort, but actually the 3/4"BSP brass adaptors stop anything running into the boiler so i'll probably not bother now.

Cheers
kev

[WishboneBrewery]

Cracking bit of copper work there Bet its fun to clean.

[Kev888]

Ha, yes I dripped some flux inside the coils at one point which was awkward to wipe away. But I think in use it should be okay if I don't forget to wash it off and clean it properly after each use. Its actually a bit more open than it may appear - with the coils going in different directions they're difficult to see through. Made me dizzy at times trying to focus on it, actually

Cheers
kev

[WishboneBrewery]

a jet wash or a good hosing straight after use should sort it. I leave my IC in after cooling and before running off as it sort of traps some of the hops behind the coil and the boiler walls so lets a little more wort drain from the hops as the level drops, it does leave more crud on the IC coils for me to clean off.

[Kev888]

Yeah that sounds good advice; think I need to invest in a decent nozzle for my hose pipe.

Cheers
kev