Air-cooled pot still. First-timer! [PICS]

[boingk]

Hi there everyone. First of all - sweet site and forums! I just can't get over the amount of information on the parent site...its almost overwhelming.

On to what I was going to ask; do many people run air-cooled pot stills? I've been lookin around for a while and haven't found mention of more than one case, and am beginning to think that people either prefer water because its a better coolant [thus smaller worm needed] or that there is another specific reason for it.

My design came about after thinking and reading and then visiting the local hardware store. 20 feet of half-inch copper tubing, one 1600W hot plate and a kettle later and I'm in business - the initial tubing from the kettle is around 3 1/2 or 4 feet high and then curves over and coils down in seven or so 8-9" loops. This arrangement is cooled with a fan that was laying around the place, and I've found that this produces results that aren't too bad at all; second run from a low abv wash [5-6%] produced 100 proof with ease. I'm now waiting on a batch of beer to finish up so I can run a brown sugar spirit wash [6.5 gal, 14% abv] and hopefully make some rum.

Sorry for the lack of pictures, but my phone camera is pretty average and I don't have a digital.

So, any thoughts on air-cooled stills?

Cheers - boingk

[blanikdog]

I asked this very question some years back and was told that the reason that air is seldom used is that water is thirty times more efficient than air.

[HookLine]

Air cooling probably works okay in cold temps, but not so good during warm weather, and especially warm humid weather.

I think Pintoshine has an air cooled pot still, so ask him. Also, the Yahoo distilling forums have some members (such as Riku) who have played around with air cooling.

[boingk]

Thanks for the info guys - I'll get in contact with pintoshine. I guess the whole water thing just seems to be a massive hassle for me, especially when I can just utilise a household fan to cool the vapor path. The whole reason this came about in the first place was because I was down at Bunnings and saw the 6m half-inch coil was some negligible amount more than the 3m one...so I bought the 6m instead of the 3m I was planning. End result, it wouldn't coil properly into the large bucket I had and so I lengthened the coil out and ran a fan over it instead, thinking 6m might be enough for the vapor to be cooled with air alone.

I guess time will tell, when the weather heats up I might not be so fortunate perhaps.

Cheers - boingk

[Hack]

Water is definately a more efficient coolant, but as long as it works, why not use air? The deciding factors are whether your air cooled condenser can keep up and you're ok with it.

[HookLine]

Here is a photo of Pintoshine's air cooled pot still.

The white box on top of the condenser coil is the fan, which sucks the air in through the coils, up the middle, and out the top.

[boingk]

Holy mackeral...thats AWESOME!

I'd love to have a coil that compact, but alas my copper-bending skills are pretty rudimentary...same as the equipment at my disposal. Its why my coil is 4ish feet high. Something to aspire to, eh?

[StabbyJoe]

From what I gather pint is quite proficient when it comes to working with copper and stainless... but theres no reason why you can't produce results like that. All I think you need is sand or salt to pack into the copper pipe and something to wrap it around... and a bit of brute force.

[boingk]

I didn't bother with the sand/salt method using my tubing...I just wrapped it around a stove-top deep-fryer that was lying around. Worked alright, but a little inconsistent in the 'downwardness' slope of the coil, so I had to tweak it a fair bit. Theres probably 5-6" between the coils, but I don't particularly mind. Makes it look a little like something from a mad-scientist-type laboratory; functional but kinda ugly...yet elegant in its crude means of achieving functionality.

Or whatever.

- boingk

[blanikdog]

... a little like something from a mad-scientist-type laboratory; functional but kinda ugly...yet elegant in its crude means of achieving functionality. ... boingk

Beautifully expressed. If your hooch is as good as your use of words. you're on a winner.

[muckanic]

As I've posted before, I've mucked around with "S" shaped air condensers, in both 1/4" and 1/2", and gave them away in favour of a Liebig. The 1/2" construction now functions as a passive water cooler in line with a recirculating pump.

I had problems with spluttering I think because I was essentially relying on later distillate to force earlier distillate out of the system. In other words, there wasn't enough gravity effect to maintain continuous flow, due to the horizontal legs of the S bends. What's the problem with spluttering distillate you might ask? Well, it wasn't just distillate but also wash, presumably due to the backpressure which develops. I would imagine that a downwards oriented spiral would suffer from even worse problems as distillate collected in the bottom turns, but maybe the presence of an initial upwards spiral ameliorates that somehow. I toyed with the idea of just using a long straight pipe as a condenser, but who has 30 ft to spare, and how do you achieve fan coverage? (Answer: do it outside on a windy day).

A sole upwards spiral solves the problem of distillate blockages, but it seems to me that it would have to be finely tuned to suit a particular power input. Too much pipe, and nothing comes out the top. Too little pipe, and either uncondensed vapour escapes or the distillate is too hot. I guess the fan speed could be used to regulate the condenser efficiency? The nice thing with a Liebig is that you can just make something that is more efficient than you will ever need, but it still works if you want to run slow. Obviously, some adjustment is possible through messing with either the water flow, water temperature, or angle of take-off, but I get the impression that most backyarders want to set and forget.

[boingk]

muckanic - I'm sorry but I don't quite understand what you're saying, that my coil must block because...its not at a constant downward angle as you would get with a straight leibig condenser set to a constant downward angle?

I think you are forgetting one essential property of a coil: it is a space saver only, nothing less and nothing more. As long as you make sure that the coil does not have any flat spots then there should be nil to few problems with the spluttering you mentioned. I've done my preliminary run and found this to be the case, as distillate either trickles slowly or drips out of the end of the coil. I did have a few problems initially but put this down to my inexperience at working copper and quickly adjusted several parts of the coil so all was evenly sloped.

The fan speed is variable, but I find I can just leave it on 'high' during a run - set and forget as you say. It point at the lower half of the coil from one side. The 20-odd feet of copper tubing in my setup is more than enough to handle a 1000W boiler with this setup in my opinion, and would be more capable still if I were able to position the fan directly under the coil so as to a) cool all of the downwards distillate path and b) work with the rising heat from the coil to help dissipate it. I actually see no reason by I couldn't do this, I'll just need to elevate the hotplate and boiler setup so as they can still join the condenser.

I'll see if I can post a few pictures, maybe this will make things clearer. Oh, and I'm in no way intending this to be a dig at you, just saying there may have been some miscommunication or misunderstanding.

Cheers - boingk

[muckanic]

muckanic - I'm sorry but I don't quite understand what you're saying, that my coil must block because...its not at a constant downward angle as you would get with a straight leibig condenser set to a constant downward angle?

I think you are forgetting one essential property of a coil: it is a space saver only, nothing less and nothing more. As long as you make sure that the coil does not have any flat spots then there should be nil to few problems with the spluttering you mentioned.

OK, I see what you are saying. You are essentially using a vertically aligned coil where the vapour enters the top and distillate always flows downwards. And I have just taken a look at Pint's set-up which is based upon similar principles. I for some reason thought the flow was bottom to top, which is of course silly. From time to time, people around here have proposed horizontally aligned coils, and those are the ones which cause blockages. Incidentally, having 5-6" between coils may not be neat and may take up more room, but it probably increases efficiency.

[boingk]

Yeah, I wouldn't want to have a sideways coil...thats for sure! Damn Copperhead Rd videoclip

My setup is pretty crude [5L demijohn in a saucepan acting as a double-boiler + the large coil], but it seems to work ok. I'll let you know how ok with some more precision as soon as my wash is done...hopefully within the next few days.

As an aside, I don't think having an upward and then a downward coil would be so bad...you'd get reflux down the upward coil and just have to cool the downward coil. Increased heat or minimised cooling would let you control the setup pretty well I imagine, but you'd want to be quite careful with the coils as per any other coil setup.

Cheers - boingk

[StabbyJoe]

Heard the vertical coil idea before - you'd have to have just the right amount of heat and a perfect number of coils, as the still will manage it's own temperature - the idea being that heat is being lost from the wash through the vapor, so the wash should not exceed it's boiling point by far. For this reason tinkering with heat input is not recommended with the exception of giving it a blast for heat up... Stills just don't work that way, and don't seem to like it when you try. So it'd be a case of having a constant some condenses and some goes through, and a hell of a job getting it to do that...

Just checking that you're using a dough or something to connect copper to glass, not a rubber bung... because that would be bad...

[boingk]

Er...rubber bungs are bad you say? Yeah thats what I'm using...covered the area in contact with vapor with aluminum foil though - less than ideal I know.

So how does this dough thing work? Just make up dough, seal pip to glass, and let the heat-up and boil cook it...then remove afterwards and dispose of?

If so, I'm sold.

Cheers - boingk

PS: Thanks for your compliment earlier in the thread, blanikdog! Let's see, eh?

[Oaty]

Er...rubber bungs are bad you say? Yeah thats what I'm using...covered the area in contact with vapor with aluminum foil though - less than ideal I know.

So how does this dough thing work? Just make up dough, seal pip to glass, and let the heat-up and boil cook it...then remove afterwards and dispose of?

If so, I'm sold.

Cheers - boingk

PS: Thanks for your compliment earlier in the thread, blanikdog! Let's see, eh?

It's described many places, but that's about it. It works quite well. It's a bit messy and requires a new seal after each use. So, some have opted for these other methods. You can also use natural cork- available from music stores- and teflon gaskets,but beware of the plastic police.[ MOD EDIT]rule 8. These forums take a very strong negative view on the usage of plastics in distilling. It simply is not safe to use in any area of hobby distilling (however HPDE buckets are acceptable for fermentation.) There simply are too many types of plastics and lack of reliable information about plastics, for us to reliably advocate its usage anywhere in distillation apparatus. Also, from past posting history, this topic seems to quickly boil down into an almost religious like flame war. Thus we simply will not put up with it, and posts about any form of plastic use will be edited, deleted or locked.

[blanikdog]

Chooks love it after it's done the job, boink. Not a skerrick of waste using dough.

[StabbyJoe]

Rubber is bad... the aluminum is also bad
Dough or cork is good... home brew shops in NZ have a range of sizes of cork bungs here, I assume that's the same everywhere... one of those should be fine. Otherwise make sure your cork source is natural, as the added resin to the other kind can do bad things from what I gather.

[boingk]

Righteo, thought some piccies might be in order so here we go. As you can see, nothing special. Just 20' of half inch copper piping with a hotplate and a lidless kettle, cooled by a household fan. Still, my runs are starting at 80% abv, and my mid-cut is holding around the 55-60% mark...heads & tails combining to give 25 to 30%. Collection is into a stainless jug with lid or a shotglass depending on stage of run. Spirit is clear & smells great - just gotta filter it through some carbon and I'll be set!

DSC00225.JPG (19.65 KiB) Viewed 6929 times

DSC00224.JPG (22.58 KiB) Viewed 6929 times

Cheers - boingk

PS: HB store doesn't have cork bungs, only rubber! Also, demijohn double-boiler took WAY too long to heat up and took too much messing around so reverted to the kettle. Very small, but not too labour intensive for somone with spare time to burn.

[muckanic]

PS: HB store doesn't have cork bungs, only rubber!

Maybe there's rubber and rubber. The one time I tried it, I wound up with flavoured distillate. My reasoning here is that hot EtOH must not only dissolve the rubber, but also form relatively low-boiling volatiles (the latter being unlikely to happen with aluminium).

Silicon bungs can be had, for a price.

[Barney Fife]

Make a wood bung; a drill and a knife is all that's needed. More tools will be handy, but at a minimum, a drill and knife is all you need.