How to make a twin coil immersion chiller
Posted: Sat Aug 09, 2014 16:05Firstly let me point out that there are many ways to make this, but this was the way I chose to do it 
This is what we are aiming to make :
Basically it is two coils, one inside the other, fed from a hose connected to a cold water tap, and another hose allowing the water flowing out to be directed appropriately - for example, maybe the hot outlet could be directed into your fermenting vessel to be mixed with a steriliser, ready to take the cooled wort?
In the pic above the outflow was going into a tub I was converting into a mash tun and wanted to fill it to test the connector I'd put in.
So, materials :
about one metre of 15mm copper tube
approx 12 metres or
- four
- two
- four
- two
- two (this is a new link - if it stops working, try googling 3/4" Tap Connector )
Note - the copper tube is punishingly expensive, but there's enough in that 25m roll to make at least two chillers - why not make two and flog one - or split the costs with a mate and make one each?
You will also need some , and a blowtorch.
Some will help on the threaded joints.
A makes much neater cuts than a hacksaw, and this one is really cheap - well worth it - but note it does leave very sharp edges, so don't push against one trying to push pipe into a fitting
You will also need to find some kind of former to wrap the 10mm copper pipe around. It's soft, so it will bend around a former without collapsing, but don't try and bend it unsupported or it will kink and be wasted.
I used two different sizes of diving cylinders - other ideas are buckets, pans, garden soil pipe - see what you can find!
Lastly, you'll need two to connect the inlet and outlet hose to the chiller.
Now, let's get on with the build
Firstly decide how high you want the coil section to be - no point in having coils above the likely wort level in the boiler, just wasted material.
The feed pipes will need to extend up above the coils to exit over the side of the boiler, and ideally the hose connection shouldn't be above the wort, just in case it springs a leak!
Now, start bending the 10 mm copper tube around the formers. Take your time. You don't need to be exact on height - the coils can be gently moved farther or closer together to make adjustments to the height.
Now we can start the fun bit - soldering!
The basics of soldering are :
1. clean the parts to be soldered with steel wool or fine grade sandpaper - so the surfaces are bright and shiny.
2. cover the areas to be in contact with flux.
3. put the parts together and heat them with a blowtorch until they are so hot that when the solder is touched to the visible joint edge it melts and runs round, filling the the visible joint. The flux ensures the solder runs into the joint and makes a solid and totally watertight seal.
There are loads of instructional videos on You Tube if you're still unsure - unfortunately they are mostly american and can't pronounce the word solder to save themselves
Beware - like I need to tell you! - the copper gets very, VERY hot - and it's an excellent heat conductor, so the heat spreads along the pipe and will take the skin off any unwary fingers
We need two elbows to go at the bottom, each with a 10-15mm reducer.
From that lower elbow a length of 15mm tube comes up the side and into a 15mm t-piece, the side exit of which has a 10-15mm reducer in.
Then another 15m tube length runs up to an elbow, and another from that elbow to the male coupler and the tap connector.
One of the 15mm pipes connects to the top of the outer and the bottom of the inner.
The other connects to the top of the inner and the bottom of the outer.
What order you do all this in is up to you.
I measured up and made the upright 15 mm pieces, then connected the coils to them, gently adjusting the coils to get it all to fit.
Tweak it here and there to get the 10mm pipes to reach the feed pipes. Chances are you'll need to cut a bit off one or more of the 10mm coils to get them to fit.
Try and get the coils evenly spaced.
To stabilize the whole structure, where pipes were touching, or could be comfortably made to touch, I soldered them together. Again, clean, flux, heat, solder - don't forget the flux!!
I did this is 4 or 5 places, and the whole thing is fairly solid now.
Eventually it'll all be together and is ready for the first test - a leak test - so run water through it in a place where you can check all the joints and see if anything's leaking. If you've done the soldering right there shouldn't be a leak!!
To fix a leaking joint, support it, heat it and run more solder in.
Once it's leak free, time for a test of it's cooling abilities.
Fill the boiler up, get it boiling with the chiller in, but no water flowing through it!
Once you're up to 100c, turn on the water.
Mine chilled 30 litres from 98c to 28c in just 15 minutes.
Initially the cooling water was going in around 8c and out at 69c
Good luck
This is what we are aiming to make :
Basically it is two coils, one inside the other, fed from a hose connected to a cold water tap, and another hose allowing the water flowing out to be directed appropriately - for example, maybe the hot outlet could be directed into your fermenting vessel to be mixed with a steriliser, ready to take the cooled wort?
In the pic above the outflow was going into a tub I was converting into a mash tun and wanted to fill it to test the connector I'd put in.
So, materials :
about one metre of 15mm copper tube
approx 12 metres or
- four
- two
- four
- two
- two (this is a new link - if it stops working, try googling 3/4" Tap Connector )
Note - the copper tube is punishingly expensive, but there's enough in that 25m roll to make at least two chillers - why not make two and flog one - or split the costs with a mate and make one each?
You will also need some , and a blowtorch.
Some will help on the threaded joints.
A makes much neater cuts than a hacksaw, and this one is really cheap - well worth it - but note it does leave very sharp edges, so don't push against one trying to push pipe into a fitting
You will also need to find some kind of former to wrap the 10mm copper pipe around. It's soft, so it will bend around a former without collapsing, but don't try and bend it unsupported or it will kink and be wasted.
I used two different sizes of diving cylinders - other ideas are buckets, pans, garden soil pipe - see what you can find!
Lastly, you'll need two to connect the inlet and outlet hose to the chiller.
Now, let's get on with the build
Firstly decide how high you want the coil section to be - no point in having coils above the likely wort level in the boiler, just wasted material.
The feed pipes will need to extend up above the coils to exit over the side of the boiler, and ideally the hose connection shouldn't be above the wort, just in case it springs a leak!
Now, start bending the 10 mm copper tube around the formers. Take your time. You don't need to be exact on height - the coils can be gently moved farther or closer together to make adjustments to the height.
Now we can start the fun bit - soldering!
The basics of soldering are :
1. clean the parts to be soldered with steel wool or fine grade sandpaper - so the surfaces are bright and shiny.
2. cover the areas to be in contact with flux.
3. put the parts together and heat them with a blowtorch until they are so hot that when the solder is touched to the visible joint edge it melts and runs round, filling the the visible joint. The flux ensures the solder runs into the joint and makes a solid and totally watertight seal.
There are loads of instructional videos on You Tube if you're still unsure - unfortunately they are mostly american and can't pronounce the word solder to save themselves
Beware - like I need to tell you! - the copper gets very, VERY hot - and it's an excellent heat conductor, so the heat spreads along the pipe and will take the skin off any unwary fingers
We need two elbows to go at the bottom, each with a 10-15mm reducer.
From that lower elbow a length of 15mm tube comes up the side and into a 15mm t-piece, the side exit of which has a 10-15mm reducer in.
Then another 15m tube length runs up to an elbow, and another from that elbow to the male coupler and the tap connector.
One of the 15mm pipes connects to the top of the outer and the bottom of the inner.
The other connects to the top of the inner and the bottom of the outer.
What order you do all this in is up to you.
I measured up and made the upright 15 mm pieces, then connected the coils to them, gently adjusting the coils to get it all to fit.
Tweak it here and there to get the 10mm pipes to reach the feed pipes. Chances are you'll need to cut a bit off one or more of the 10mm coils to get them to fit.
Try and get the coils evenly spaced.
To stabilize the whole structure, where pipes were touching, or could be comfortably made to touch, I soldered them together. Again, clean, flux, heat, solder - don't forget the flux!!
I did this is 4 or 5 places, and the whole thing is fairly solid now.
Eventually it'll all be together and is ready for the first test - a leak test - so run water through it in a place where you can check all the joints and see if anything's leaking. If you've done the soldering right there shouldn't be a leak!!
To fix a leaking joint, support it, heat it and run more solder in.
Once it's leak free, time for a test of it's cooling abilities.
Fill the boiler up, get it boiling with the chiller in, but no water flowing through it!
Once you're up to 100c, turn on the water.
Mine chilled 30 litres from 98c to 28c in just 15 minutes.
Initially the cooling water was going in around 8c and out at 69c
Good luck
