Freezing an immersion chiller in a bucket of water?

In the spirit of using less energy, and also because I'm lazy, I've been considering trying to chill my wort without running water or electrical input. I usually boil my wort up high on a table so my 1.5 year old son can't reach it. I just installed a weldless shutoff valve on my brew pot, and have considered freezing an immersion chiller or a small finned tube radiator in a bucket of water. On brew day, I'd just route the discharge from the kettle valve thru the wort chiller and into my fermenter. It would also mean I could add my hop back in between the kettle valve and cooler, and have almost instant cool down after the hop back addition.

If the chiller was in a block of ice, I believe the surface of that copper coil would remain very close to freezing. As soon as a little bit of hot wort went thru the coil, there would be a thin layer of 32 degree water around the coil. This layer of water would slowly increase in size, but with the huge heat sink of ice around it, would remain close to freezing.

I guess my questions are: has anyone ever done this? and if so, is 25 or 50 feet of copper tube frozen inside a block of ice a sufficient length to cool wort down to 80 degrees or so based on the relatively slow volume of water that goes thru the chiller because of gravity? It would only be a single pass thru the chiller.

I've already tested the flow principles of this, and there is enough head from the height of the brewpot to flow through all of my devices. I guess I need to test it with real boiling water and a real frozen ice block...

Oh, and I know that the energy used to freeze the block is probably more than a pump would consume

That sounds like a fun experiment...I'm sorry I don't have any experience with it to lend but I'll look forward to reading your results!

The wort will not exit the chiller at anywhere near pitching temps. I can't imagine you'd get much temp drop on 1 pass. Maybe 10 degrees? I don't know.

You would have to recirculate and likely keep adding ice.

I don't doubt this, but I think I am going to have to experiment

It will start out good for the first short amount of liquid until the ice starts to melt and then you'll have an issue as it will no longer be touching the ice (the ice is less dense than the water, so as it heats it will pull away from the IC).

The coldest water you can get would work much better.

If you dont mind the corrosion, mix salt into the water and then chill it below freezing, it will work much better. It's colder and you dont have the issues that you would with ice.

Better yet, get some glycol and super chill it and dip the coil in that, or use vodka sense it also has a lowered freezing point compared to water.

The thing is, I'm not too concerned about the ice receding away from the coil, because the small volume of water surrounding the coil will be very cold since it is still in contact with a huge chunk of ice...

However, I really like your glycol idea...I could just get one or two gallons of antifreeze, and chill that down to around 15 degrees.

Ice is actually a great insulator, and I don't think this will work very well after a minute or two. I thought chilling in a snowbank was a great idea, as we have unlimited amounts of the white stuff. It worked great for about 5 minutes, then the snow that had melted immediately around the pot formed an "igloo" and actually slowed the cooling. I think the same thing would happen with an IC in ice.

The heat from the wort will keep the ice melting, but the cold from the ice will not replace the warm water as fast. You'll need to find a way to keep the melted water circulating so it can exchange temperature with the ice. Otherwise, all it's doing is insulating the coil from the ice.

Sounds like a fun experiment! Let us know how it goes.

dmmt Yooper! LOL!

Yeah, that's why I'm thinking the supercool antifreeze would work better, because you could keep it circulating. It's also a heck of a lot easier to fit a couple gallons of antifreeze in the freezer. I'm going to try it!

What Yooper said above. I'd also be concerned about freezing the chiller and damaging it, I've seen Immersion Chillers, Counterflow Chillers & Plate Chillers ruined because they were left outside in freezing weather with just the tiniest bit of water in them.

I don't think it matters how cold you keep the water around the chiller.
If you don't recirculate the wort, I can't see you getting to pitching temps in one pass.

You said you tested the flow, how long will it take to drain 5 gal through the chiller?

About 8-10 minutes. I agree though - I sort of doubt that one pass will be enough, but would love to be surprised.

When you use an immersion chiller in it's classic way, you have a large volume of hot fluid (the wort) that needs to exchange its heat with the relatively small surface area of the chiller. The closer the wort gets to the temperature of the fluid inside the chiller, the slower the heat transfer. What I'm trying to do is reverse the fluid flow so that the continuous stream of low speed wort is exposed to an almost constant temperature, really low-temp fluid. I don't know what benefit this will have, if any. But I'm not 100% convinced that a 15 degree heat sink of glycol can't cool down slow moving wort in one pass.

cwheel said:

But I'm not 100% convinced that a 15 degree heat sink of glycol can't cool down slow moving wort in one pass.

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That glycol would have to be kept in motion to be effective.

wyzazz said:

That glycol would have to be kept in motion to be effective.

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That is the premise behind a counter-flow chiller. The cooling liquid (in my case, water) goes one direction, while the wort flows the other. There is turbulence and it's a great way for a HEX to work.

I think you'll need more than 2 gallons of glycol. I think with enough glycol being constantly agitated and a slow wort flow rate it could work.
Not sure of the benefit but should be interesting.

Gonna need lots of electricity to get that glycol down to 15F.

There is also the risk that the expanding ice would rupture the copper lines, which would ruin your beer.

Yeah, I think ice is off the table for sure (for many reasons). Still might try glycol or salt water.

Because I'm a nerd....


You need to pull out about 5500 BTUs to bring 5 gal of water from 212F to 80F.
The amount of pure glycol needed to absorb this heat from a starting temp of 15F and not rise above 80F is about 15 gallons.

What about the energy to convert 2 gallons of ice to 60 degree water. I know it's a lot more because of the latent heat of fusion, or whatever the proper term is...

If you want to save energy, making ice cubes to mix with cold water will use less energy and be way more efficient at chilling than making/using a block of ice. When I first started brewing I used a coil of copper inside a 5 gal bucket full of ice water as a chiller. It was gravity fed, and as long as I kept stirring the ice water it worked great.

JuanMoore said:

If you want to save energy, making ice cubes to mix with cold water will use less energy and be way more efficient at chilling than making/using a block of ice. When I first started brewing I used a coil of copper inside a 5 gal bucket full of ice water as a chiller. It was gravity fed, and as long as I kept stirring the ice water it worked great.

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I still do this but only after I run through a cfc. My cfc gets it down to 68 degrees, after the coil in the ice water it enters the fermenter at 55 degrees for lagers.

cwheel said:

What about the energy to convert 2 gallons of ice to 60 degree water. I know it's a lot more because of the latent heat of fusion, or whatever the proper term is...

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Interesting.
Assuming you mean 2 gal of water frozen into ice.
About 2900 BTU. 4 gal of frozen water gets you to 5500 BTU.

cwheel said:

When you use an immersion chiller in it's classic way, you have a large volume of hot fluid (the wort) that needs to exchange its heat with the relatively small surface area of the chiller. The closer the wort gets to the temperature of the fluid inside the chiller, the slower the heat transfer. What I'm trying to do is reverse the fluid flow so that the continuous stream of low speed wort is exposed to an almost constant temperature, really low-temp fluid. I don't know what benefit this will have, if any. But I'm not 100% convinced that a 15 degree heat sink of glycol can't cool down slow moving wort in one pass.

Click to expand...

WARNING: SCIENCE CONTENT AHEAD...

You are on the right track with your thinking about reversing the scenario, to where you would have a small volume of hot wort (at any given time) passing through a relatively much larger chilling volume. However, the concept of using an ice block to do this is inherently flawed. Here's why:

There are three basic methods of heat transfer: conduction (i.e. direct contact), convection (the flow of heat down a gradient, from a hotter region to a cooler region), and radiation (not really applicable here). The 'traditional' immersion chiller works because your heat exchange fluid (typically water) is being constantly 'refreshed', in order to maintain a heat gradient (think convection). If the exchange fluid is not 'refreshed,' you have a situation called 'natural' or 'free' convection. It is not nearly as efficient.

In the scenario of your chiller-frozen-in-an-ice-block idea, you would quickly transition from the realm of conduction to the realm of convection, once the ice immediately surrounding the coil is liquified. Without agitation to maintain a sharp temperature differential, you would build up a gradient effect, where the liquid closest to the coil is hottest, and the liquid at the water/ice interface is the coldest. This liquid layer would still perform heat transfer, sure, but it would be painfully inefficient, and I imagine quite frustrating.

You would be much better off immersing a coil in a bath of ice water that you could agitate up-and-down while the wort is draining through it. Or, perhaps someone could design a device where a cooling fluid flows constantly on the outside of the coil, while wort flows through the inside....

What he said, an agitated ice bath (with lots of ice or fresh water) would work or you could just run water through it like normal people.

at 15f in glykol if you still consider this arent you conserned that the first wort that passes trough will freeze?

RensBerserker said:

You would be much better off immersing a coil in a bath of ice water that you could agitate up-and-down while the wort is draining through it. Or, perhaps someone could design a device where a cooling fluid flows constantly on the outside of the coil, while wort flows through the inside....

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Hey that sounds a lot like my Counterflow Chiller!

I messed with this several years ago. I quickly realized that stirring is required. If you used chunks of ice in a big enough volume that could easily be stirred, then it could work.

Flow is the key - both of the hot wort and of the chilling liquid

I'm thinking of coiling my feed hose into a large garbage can filled with water and frozen soda bottles.I figure the water should be close to freezing when hitting my chiller coil.Wouldn't salt water be better?colder?

lylo said:

I'm thinking of coiling my feed hose into a large garbage can filled with water and frozen soda bottles.I figure the water should be close to freezing when hitting my chiller coil.Wouldn't salt water be better?colder?

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The bottles will work, but not near as well as ice. The smaller the bottles the better. Salt will only allow you to use a higher ratio of ice to water while still being liquid enough to stir. It won't actually make anything colder.

A little off where the topic has gone, but back to the OP- i'm not sure if this helps with any laziness or energy efficiency but you'll use less water: i brewed 10 gallons of IPA today after moving out of the warehouse i usually brew in and back to my garage. didn't consider that i'd pulled both of my 10 ft frost-free faucets out of the ground with a backhoe a couple months ago so i had no way to hook cold water to my immersion chiller. I ended up with two garbage cans full of snow and melt off with a sump pump pushing the water back and forth. added snow every once in a while. worked pretty well and beats putting all that water down the septic tank.