Homebrew Wort Cooler, Twin Coil Immersion Type




Intro: Homebrew Wort Cooler, Twin Coil Immersion Type

Wort (pronounced Wert) is the hot malt liquor that beer is made from, before the yeast can be pitched (added to the Wort) it must be cooled down to around 30°C other wise the yeast will be killed. This cooling process if unaided can take hours which besides being impractical exposes the the freshly made beer to airborne bacteria and undesirable wild yeasts. For this reason the Wort is cooled down to a practical temperature using a Wort cooler or Wort chiller.

There are two common types of Wort cooler counter flow and immersion, this instructable details the build process for the doommeisters twin coil immersion Wort cooler. Immersion Wort coolers as the name suggests are immersed in the hot Wort and cold water is passed through the cooler thus bring the temperature of the Wort down.

For small batches immersion coolers are much easier to clean and sterilise than counter flow coolers, this is because they can be sterilised in the hot Wort itself by adding the cooler in for the last 15min.

There are many plans and photos on the Internet for this kind of cooler so this is not really an original design more an interpretation.

Step 1: You Will Need

Metric sizes are shown, American imperial sizes in brackets.


1.5m of 15mm (1/2”) OD copper pipe.

15 – 20m 10mm (3/8”) OD copper pipe.

2, 15mm (1/2”) copper Tee fittings, sweat or solder ring.

6, 15mm (1/2”) copper elbow fittings, sweat or solder ring.

4, 15mm (1/2”) to 10mm (3/8”) reducing fittings, sweat or solder ring.

Solder, 99c lead free.


4” pipe and 6” pipe or similar to use as coil formers.

Pipe cutter.

Gas torch.

Heat resistant mat.

A selection of other hand tools.

Additionally you will need some hose or food safe tubing to connect the cooler to cold tap and back out to drain.


Step 2: Pepare 15mm Pipe

Using the pipe cutter cut the 15mm pipe into 4 x 100mm lengths, 2 x 350mm lengths and 2 x 35mm lengths. These sizes can be adjusted to make your cooler suit the size of your Wort boiler.

Step 3: Form Cooling Coils

Using a short length of 4” plastic pipe the middle coil can be formed by bending the 10mm copper around the pipe. Do this slowly to avoid kinking the pipe, when 12 to 15 coils have been formed cut the copper coil from the and leave 300mm or so as a tail for assembly.

Repeat the process using a 6” or 8” pipe or bucket to form the larger outer coil.

Step 4: Dry Assemble

Dry assemble the cooler, make the flow and return pipes by fitting an elbow to the bottom of one of the 350mm lengths of 15mm copper to the top of this add a Tee fitting such that the T connection is offset tot the side. Into the other the other end fit a 100mm length of copper pipe and fit an elbow to the top add a final 100mm length to form a tail such that the cooler can be connected to hose pipe. Into the T port fit the 35mm length of copper and insert a second elbow.

Now dry fit the 2 coils to the flow and return pipes, ensure that each coil is piped to the flow and return pipe.


Step 5: Solder

When you are happy with the dry fit it is time to solder each of the joints, clean each joint with wire wool or scotch brite in order to remove the oxidised layer from the copper. Flux each joint well and solder.

In order to add some rigidity two lengths of flattened copper pipe were soldered between the flow and return pipes.

Step 6: Clean

Before use the cooler must be cleaned, in the first instance this means removing flux and oxidisation from the pipes with wire wool or similar. The cooler should then be thoroughly washed and sanitised before use.

The doommeister doesn't have a brew planned for a week or two, in use photos to follow.

Step 7: In Use

Cleaning was done using a scouring pad and soapy water to remove flux and oxide deposits, then clear distilled malt vinegar was used to clean the copper. Before use the cooler should be rinsed in clean water and sanitised in the last ten minute of the boil.

In use the cooler took around 8 minutes to cool the Wort from boiling to 29/30º.

A couple of usfull links below

Commercial wort coolers
This cooler was my inspiration for the twin coil design.



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    25 Discussions


    8 years ago on Introduction

    damn you beat me to it!

    well ill post mine in a bit anyway as its a solder free version. keep up the homebrew!


    1 reply
    el greenoChard

    Reply 3 years ago

    where did you go to chard? ?

    David P

    7 years ago on Introduction

    wow, I like the over engineered look! I was going to say that I built a much MUCH simpler cooler and when I use it with my tap wide open the effluent is quite hot, I then got to thinking how much hotter would it be with that much surface area... My next batch I will have to measure the inlet, wort, and outlet. I would like to see the delta on your chiller as well


    8 years ago on Introduction

    Very cool design, i hate to clean my counterflow chiller ;-)

    In it's first use the cooler took around 8 minutes to cool a 23l batch of wort. This of course would vary based on flow rate and temperature of water used as the coolant.

    Not sure yet as it hasn't been tried out , I'll edit the instructable when I've used it for a brew and post some in use photos as well.

    I would expect based on similar designs that it would cool the Wort in 15 - 25 minutes for a 5 gallon batch.

     Nah, it'll do it much faster than that I reckon. I made one like that but with only one coil and it cools in just over ten minutes. Of course it depends on the flowrate of your taps too.

    I look forward to hearing how it does, it looks really cool!


    8 years ago on Introduction

                 Although alcohol is not present in the mix yet I just don't like the idea of solder anywhere near a brewing process. The cooler is great but I would go with flare nut fittings instead of solder. There are too many historic cases of lead poisoning in home brews. Flare nut fittings would eliminate any risk. Keep in mind that another person might use that coil to condense alcohol. It is just not a good idea to use solder.

    2 replies

    Reply 8 years ago on Introduction

    You will notice that every time solder is mentioned it is followed by Lead Free. The solder used in the project was grade 99c which is copper/tin solder (0.7% Cu),  lead free solder for potable use. However there are impurities in any metal product so there could be some.

    I would not recommend leaded solder for any potable use, but am unsure whether lead is even soluble in alcohol (if someone knows than let me know 'cause I would want to poison myself either). Most cases of lead poisoning in homebrew seem to be attributable to the use of older enamelled vessels with lead based pigments.

    As for flares or compression fittings I decided against these as they would be more difficult to sanitise.

    With regard to condensing Alcohol then if someone wanted to do this then they should make them selves cogisent of ALL the risks involved with that particular process.


    Had another think about this and it occurs to me that the lead content of the free cutting brasses found even in fittings for potable uses such as CW614 is around 3%, even DZR such as CW602 has a Pb content of around 2.5%, so lead  free solder may actually be better than any sort of brass nuts (for the next few years at least until lead free brass is a requirement  in places other than CA). The lead is to make the brass more easily machineable.

    I think the best option if anybody was concerned about this would be just to use a loop of copper or stainless and not submerge any fittings. I have gone back to thinking this isn't much of an issue.


    Reply 8 years ago on Introduction

    Not cheap. If you buy from B&Q or Wickes then a 10m coil costs £27 or so, I am lucky enough to have several decent plumbers merchants nearby and picked up the 25m coil for around the same price.

    I estimate the build cost around £35 including the fittings


    Reply 8 years ago on Introduction

    Well the price of copper and brass has been steadily rising for the last 5 or so years and shows no sign of dropping just yet.

    When I get round to putting my shed up I think I might well be reading your instructable, for information purposes only of course.


    8 years ago on Introduction

    looks professional, good job on the coil.

    For homebrewing (>23L), what's the benefit of this method over letting it stand to cool before pitching?

    4 replies

    Reply 8 years ago on Introduction

    Here's the thing, if you don't cool your wort quickly, you get some very bad favors in your beer.  (As in undrinkable).  Not something you want in your own beer.


    Ambient cooling for a batch of say 20 litre can take 4  or 5 hours, maybe more, you don't want to put a lid on the fermenting vessel lest it get stuck due to the vacuum and you really don't want to expose it to the atmosphere for this long. Also besides the fact that waiting is dull and risks severe drunkenness on your last batch cooling the wort down quickly aid the clarity of the beer by precipitating the malt proteins out of the wort.


    Reply 8 years ago on Introduction

    The author also mentioned that with ambient cooling, you run the risk of your wort being contaminated with airborne bacteria and possible wild yeast, either of which can ruin a good run of beer.