Building a Keg Still (Bokakob Design, Reflux Still)

Picture of Building a Keg Still (Bokakob Design, Reflux Still)
Building a Keg based reflux still using the bokakob design, with some modifications courtesy of the distilling community.

Before you start check the laws in your local area, some places you cant even own a still let alone use it to make a drinkable product, check it out first. I know in New Zealand you can make your own booze and in the UK you can have a still that makes up to 5L if you have a permit.

I wanted to have a go at making my own spirits, Rum, spiced rum, vodka, schnapps whatever took my fancy really and to do this I knew I needed a still, now there is very cheap and easy to make stills out there, you can connect a copper coil to a stockpot and put the coil in water and off you go, this is known as a Pot Still, a very crude one but it will work, just not very efficiently.

I wanted to get the best out of my still, plus I like the challenge or building something new and something that looks cool, and it's nice to say "I own a still"

the following instructable comes from weeks of research in to making stills, running them and making actual drink able products.

I have attached an image of the original Bokakob still design, but in summary it's a large copper pipe with 2 plates near the top at a 30 degree angle with a copper condenser coil at the top which water runs through to cool the valorised alcohol which then drips down hits the plates and then it can be collected.

for those that don't know what a reflux still does, basically it allows the alcohol to be re circulated around the column each time it drips back down the center it picks up more alcohol from the vapour which means you get a much purer product that from a pot still. having said that sometimes you need a pot still to keep the flavour of what you produce, the Bokakob design allows you to run it both as a reflux still and a pot still.

during my research I found this animation of the bokakob design working, check it out.

also there is a ton of information out there on this still design, but you have to take it all with a pinch of salt and work out what is good or not.

with this still we should be able to produce around 90% pure alcohol if not more, about 3 litres from a 20L fermented mix, also known as WASH or MASH, the wash should be around 14% alcohol by the time its finished fermenting, more if you use turbo yeast, it really depends on the recipe.

you can get so much information from the home distillers website, they have some great recipes and information on their site and on their forum.

if you need more information on the bokakob still design check this wiki out
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MarianoD16 days ago

I was following your instructable, but I have some trouble welding the plate inside of the tube. I'm using a silver based bar (strong welding), but I cant reach the correct temperature with the torch I have, and because of that the welding isn't good. What kind of soldering bar are you using? In the picture appear to be a tin (Sn) based with out lead, but if this is the case, is the Sn safe to use in this equipment?.

Thanks, and sorry for my bad english

n1cod3mus (author)  MarianoD16 days ago
I'm using lead free plumbing solder, common stuff from most hardware stores.
MarianoD11 month ago

Hello, I have some doubts about the size of the pipe, you said 2" or (54mm), but 2" are not the same of 54mm. 54mm should by 2 1/8" . So, what size of pipe whould I buy?

n1cod3mus (author)  MarianoD11 month ago
they are the same, 2" is the inner diameter and 54mm is the outer diameter, it just depends on how your plumbing shop refers to them.

Oh I see, thanks for your reply. I will buy 2" then.

piotrp25 months ago

hello!I have question .how you fit the thermometer ? the is no any leakage?

ant the pressure hole on top ,no leakage ,no vapur?

n1cod3mus (author)  piotrp25 months ago
thermometer, slides in to the hole under the plates and you seal it with a few wraps of PTFE tape.

no vapour does not come out the top, if your coil is run correctly then the vapour will be cooled and turned back to liquid before it gets there.
zamo277 months ago
One more question
Where do the neddle valves go and what's the purpose of these? Are they left slightly open at any given stage during distillation? Can you explain pleAse
n1cod3mus (author)  zamo277 months ago
you put one on the output, you need to control the flow out so that it refluxes, you should be aiming for about 2 drips a second
zamo277 months ago
Do you think I could combine the two designs, pot still and reflux in one
I'm thinking about using the same column and invent some sort of attachment for the condenser in pot still mode?
n1cod3mus (author)  zamo277 months ago
yes i have described a detachable head where the condenser is, if you make this column really short then make an extension column with an easy flange at each end, and use a tri clamp to connect the 2 that would work, thats what my column now looks like.
jqdesigner8 months ago

Could this type of still be used to make gin?

n1cod3mus (author)  jqdesigner8 months ago
it could if you run it in pot still mode, with the valve fully open so it doesn't reflux. put the botanicals in a basket inside the column
adamant6289 months ago

This is a great instructable. Do you have an update for your update?

I was also wondering if you have an easy way to remove all of the packing from the column for cleaning? Maybe a copper wire with a hook at one end?

n1cod3mus (author)  adamant6289 months ago

I havnt done much on the new column so no update, other than the scrubbers get really dirty very fast. to get them out I have a grabber tool used for picking up screw, but you could use a stick with a barbed prong on the end.

woodduck11 months ago

great instructable love it easy to follow. I only thing I did different was the conection to the keg. I used a 4inch milk fitting on the keg so I could easily clean the boiler then made a cone to a 2 inch fitting and it works well. thanks for your instructable keep up the good work.


Has anyone had issues with a 2" clamp? looks like it should be 2.5" or so.

n1cod3mus (author)  FatalExeption1 year ago
the clamp size refers to the size of the pipe not the ferrule
serjinio1 year ago

Very good, thank you.

gn0stik1 year ago

For those who don't want to make their own flange. They actually manufacture copper triclover fittings that you can solder directly onto your pipe. They are a tad expensive, but you know it'll work, and you won't destroy a column trying to figure out how to flange properly.

n1cod3mus (author)  gn0stik1 year ago
I would love to know where you get them? I looked around and couldn't find anything other than stainless steel
I found some on eBay. I any remember my search term though.
n1cod3mus (author)  n1cod3mus1 year ago

and after saying that I did a search on ebay and found one listed, DOH! but it was £17 plus postage from the US

wolfgang642 years ago
This a is very intertesing project. Unfortunatly a home still in the states is very illegal but I have another use for this. Can you tell me what the psi or kgpsi is for of these stainless steel kegs is? The idea is to build a dune buggy and use the ambient engine heat to aide in making woody alcohol to fuel it. I know it would take about three kegs for the different stages but what can these vessels take in terms of pressure? Thank you Karl.

This won't work, It takes too long to heat the mash to get the reaction going. You just don't have enough heat from an engine to make it work well. You'd burn 100 times the fuel heating the engine, than you would make.. You'd be better off with a wood gasifier.

What if you use a fresnel lens or a series of large maginifiying lensis and paint the target flat black? set a compass in it and plot ideal sun latitude? This all a theoretical but please let me know your thoughts. Thank's K.
That would get hot enough, maybe too hot, though. It could ignite the alcohol vapor. Also, it would still take a long time to get going. You over estimate how long it would take to heat that much fluid. And you could only run it during the day. Seriously, look into wood gasification.
n1cod3mus (author)  wolfgang642 years ago
mine says 4.14 BAR, you would have to heck with the manufacturer in your area for your keg.
Is that barometeric preshure? I don't want to make something I can drink I want to make ethanol that will power a large air cooled engine. ATF (alchol Tobbaco and firearms dousn't have a problem with that.
n1cod3mus (author)  wolfgang642 years ago
the process is the same either way, I would assume thats barometeric pressure as I said mine has 4.14 BAR stamped on the side of it.
wolfgang641 year ago
Than'ks code3 but I am looking for psi.
n1cod3mus (author)  wolfgang641 year ago

Just a thought if you are trying to produce high PSI then i would suggest a gas cylinder of some type, they make stainless steel ones.

BARKing1 year ago
I have been testing some turbo yeasts. One is the Extreme20 and the other is supper 6... The first trial was messed up in that the guy running it through the still changed methods between batches but both came out with clean flavour. I started another batch of each on the same day and the extreme 20 was fermenting vigorously with in 12 hours, super 6 took 48 hours. In the first week it was mostly fermented out but I left it for a month and a half checking SG every week.
The extreme 20 started at a SG of 1.120 and finished at 0.980 which makes it about 22% alcohol. The other started a bit lower and has finished at about 18%. When you have to take the time to boil 5 gallons I want max product for my time. If they both produce the same quality product in the end I will be using the extreme 20 in the future. I will continue testing other yeasts as I find them.
n1cod3mus (author)  BARKing1 year ago
I think you will find with a starting sg of 1.120 and an finish of 0.980 thats 18% use the calc on

if you are using a reflux still then i guess you can get away with a turbo yeast as it strips the flavors anyway so you don't have any worry about a yeast flavor.

but if you are using a pot still for flavored spirits I would say don't use turbos as it will effect the flavor.

I thought it is 18% if you stop at 1.000 but it fermented to 0.980 adds another few % going by the hydrometer. I also took the brix with a refractometer and did the calculations with the SG and got 22%. I will have a look at the site thanks.

Depending on the quality of the still setup and skill levels, I have seen a wide variety of results from my customers who use the same yeast. For some it is important to have a clean flavoured yeast, not all turbo yeasts are equal. Some of them were trying to make vodka with a pot still, now they have towers.

n1cod3mus (author)  BARKing1 year ago

i actually dont use this still head very often anymore i made a simple pot still head as i'm doing flavoured stuff now.

check out my Jack Daniels instructable i released the other day

n1cod3mus (author) 2 years ago
Ok so I ran this the other week with a Peach Mash and got virtually no flavour, turns out that due to the height of the column the flavour vapours cool too quickly so never make it out. only option would be to make the head of the column detachable so you can attach it directly to the still. Or build a pot still..... think I will make a pot Still, gives me another instructable lol.
Try it with a column about 8 inches high, no packing or coil. I get a good flavour doing that.

Might be interesting to make a shorter column, and then make a riser with tri-clamps on both ends, that you can attach to the column when you want to make something a little less flavorful, like vodka, or flavor it yourself with say cinnamon, apples, or oak.

n1cod3mus (author)  gn0stik1 year ago

I have recently made a new version with a detachable head which can attach directly to the keg

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