Preheater design question

[Pikey]

I bought a book many years ago called "Moonshine bible" - which is old - but reprinted by a guy in 1996. It was too hard for me to understand in those days and stood neglected. I just read it several times over the easter period and am convinced that one of the stills explained is excellent in that it uses the next wash, queueing up as the cooling liquid for a worm and the partially condensed fluid is then fully rectified and a further cooling system knocks down all the product. It is called "Dorn's still" and the charentaise system of preheater seems to be based on a simpified version of it. Dorn's still contains a section below which seems to act as a thumper for further rectification, with overflow going back into the main still and is called a "compound still" in the book.

I want to use part of this design as a preheater.

Now I have a bit of a problem; My pot takes around an hour to get up to temp, then about 2 hours to do the run proper. This means that there is around twice the power going into evaporating the product as in heating the wash. So if the vapour is condensed in a worm in the next wash tank, that should mean that the next wash gets up to "producing temperature" some time before the first run is exhausted.

Dorn's still has a vent pipe allowing any vapour produced to be incorporated into the first coil of the worm and thus in the production run. In some ways this would be great, because when the first run is exhausted and the next wash is discharged into the still proper, it would already be partially distilled. HOWEVER I am not happy with that, as I do single or 1,5 runs and need to get rid of the fores on each run.

As far as I can see I have two choices; a) incorporate a bypass valve so when the wash gets to temp, the valves close / open and the remaining bypasses that part of the worm or b) reduce the coils in the worm so not all of the heat is extracted.

Opinions please ?

[still_stirrin]

Is this the design you're referencing Pikey?

compound still

From this early publication?

distiller's guide

Quite an exhaustive read. It is difficult to answer your question without spending more time studying the design. Perhaps others are familiar with it. Sorry I can't help much at this time.
ss

[Pikey]

On the contrary ss - that's a BIg help ! - I was wondering how to get that diagram onto the thread - that's it exactly. - It's an old book - no mention of stainless steel or plastic in any form and he refers to some 1907 legislation as though it had just come out. It is clearly out of copyright as mine still has most of the title page you show intact. You're right though - quite a weighty tome - but shows a lot of the principles quite clearly imo.

Mine has been re-issued by a guy in uk as "Moonshine bible" in 1996 - if you have the book, I found the sections on "rum" and "molasses and skimmings" distillation quite interesting, especially the reference to "dunder" - although it is at some variance with what we are believing is "the right way" to use dunder.

The principle is fairly simple I think - the still uses the pending wash as a cooler and preheater. There is a fill pipe for the next wash to go into the still but interestingly no tap on the still to let the exhausted mash out ! (I guess that's a mistake)

The third part is just another condenser with a parrot stuck on the end. The parrot has an air vent to let air out of the worm. I would dispense with the third part entirely and use soething like a liebig.

I think he is using the "Warm worm" to condense a lot of the water but keep most of the lower BP elements intact in the vapour, then the "sort of thumper arrangement" to condense more of the water and finally the main cooler to condense the higher abv product.

Thanks for that mate

[shadylane]

I think something like this would be simpler

[Badmotivator]

I made myself a simple little preheater recently. I wanted to cut the time down on my three-strip days, so I bought a coil of copper and put it in line on my condenser output hose. I drop it in one or the other of the two buckets of wash that are waiting to be the next charge. I aim for a condenser output temp of 160 F, and I watch the temp of the bucket I am preheating. When it is around between 140 and 150 F I remove the coil. It cost me around $30 and saves me about 45 minutes on the next boil each time.

[still_stirrin]

...Mine has been re-issued by a guy in uk as "Moonshine bible" in 1996 - if you have the book, I found the sections on "rum" and "molasses and skimmings" distillation quite interesting, especially the reference to "dunder" - although it is at some variance with what we are believing is "the right way" to use dunder...

I found the book (all 340-some pages) online on Google books.

Google it and it can be downloaded...for free.
ss

[Pikey]

I think something like this would be simpler

Yes I've seen that - classic representation of Charentaise I think ? - don't fancy trying to make that squashed spheroid tho' - Clearly that is done to extend the time the lyne arm extension goes thro' the wash - so I'll take that as a vote for "shorter coil"

Trouble is How short ? and - where does the expanded air in the top go as it gets warmer ?

I made myself a simple little preheater recently. I wanted to cut the time down on my three-strip days, so I bought a coil of copper and put it in line on my condenser output hose. I drop it in one or the other of the two buckets of wash that are waiting to be the next charge. I aim for a condenser output temp of 160 F, and I watch the temp of the bucket I am preheating. When it is around between 140 and 150 F I remove the coil. It cost me around $30 and saves me about 45 minutes on the next boil each time.

That sounds like a vote for "Bypass valve" to me - I'll take it as such

Thanks for those temperatures btw.

...Mine has been re-issued by a guy in uk as "Moonshine bible" in 1996 - if you have the book, I found the sections on "rum" and "molasses and skimmings" distillation quite interesting, especially the reference to "dunder" - although it is at some variance with what we are believing is "the right way" to use dunder...

I found the book (all 340-some pages) online on Google books.

Google it and it can be downloaded...for free.
ss

Lol - and it's bigger than mine as well ! - I only have 200 pages and that diagram is "Fig 11" in mine - I highly recommend it for it's "four types of fermentation" as well as all sorts of other stuff.

[NZChris]

Mine is designed after the Charentaise still. You don't have to build an onion, any shape will do as long as they are the same volume. Two kegs would be good.

The coil in mine is one and a half turns of 1/2" copper, placed close to the bottom so that it is always submerged and heats from the bottom up instead of from the top down, as happens when the entry is too high.

Boiler and preheater are lagged.

The Liebig cooling water is automated, controlling the condensate temperature. Currently only the still, but another controller is on its way for the preheater Liebig.

As the temperature of the preheater rises, the amount of heat transferred drops, so your worry about how much gets distilled from the preheater is unfounded. You might be able to stuff that up by using too many turns of coil and having the entry too high.

With equal washes my preheater barely takes a foreshot. If the last charge is smaller it will take way more than a foreshot. I have done two spirit runs in parallel, a large run in the pot and a smaller one in the preheater.

Three strips in a day is a doddle. My last Birdwatcher's run was seven and I was all cleaned up and at the pub by five.

[shadylane]

I made myself a simple little preheater recently.... I bought a coil of copper and put it in line on my condenser output hose....

That's one of the ways I do it also, simple and cheap

[The Baker]

A pre-heater is on my to-do list, after I finally get my tiny still going and then the bigger one...

I think it would work best if you start with the boiler, say, half full; distillation would start much sooner. Then the next wash would be partly pre-heated already, for you to top up the boiler....

Geoff

[The Baker]

I made myself a simple little preheater recently.... I bought a coil of copper and put it in line on my condenser output hose....

That's one of the ways I do it also, simple and cheap

If you had it in the condenser INPUT line like those old French stills it would also act as a 'pre-condenser' (more efficient condensing) and pre-heat the wash much more efficiently too.

Save more time, save more money on power and use less water/ need less cooling for the condensing water. Those Frenchies had it worked out.

Geoff

[NZChris]

If you get your arse into gear you can use the backset from the first run plus Leibig heated water to have the next generation of rum or UJSSM in the can, up to ferment temperature and bubbling before the second strip finishes.

[Swedish Pride]

i envy you lads who have room for this stuff.
would love to see the finished preheater if/ when you make it.

[NZChris]

i envy you lads who have room for this stuff.

Mine is stacked. The footprint is only twice that of the pot on it's own, but if I had been short of room I could have stacked them on top of each other and had the same footprint.

[Swedish Pride]

I run in the kitchen so have to move it out to the shed each night after every run, pain in the tits but that's suburbia in Ireland for ya

[NZChris]

The idea of the preheater is to cram multiple runs into one session, so that by the time you have to cart it out to the shed, the job is done. Three strips today, spirit run tomorrow, likker aging in the cellar.

[Pikey]

Mine is designed after the Charentaise still. You don't have to build an onion, any shape will do as long as they are the same volume. Two kegs would be good.

The coil in mine is one and a half turns of 1/2" copper, placed close to the bottom so that it is always submerged and heats from the bottom up instead of from the top down, as happens when the entry is too high.

Boiler and preheater are lagged.

The Liebig cooling water is automated, controlling the condensate temperature. Currently only the still, but another controller is on its way for the preheater Liebig.

.............

Excellent advice here Chris - thanks a lot.

one and a half turns ? - so coiled through 180 degrees so it is facing towards the input - then another 180 degrees so it faces the same way it did originally and another 180 degrees so it is outputting on the same side it went in on - right ?

So it appears you have another Liebig on the preheater, to intercept the foreshots and any further distillate - as well as venting the air from the preheater ? is that right ? - effectively a master still and a slave still ?

I was wondering whether to do it that way myself, in which case, the more heating could be worked into the preheater the better I would think. The quicker the process and the least electric and cooling water usage.

[Edit - when you say the cooling water is automated - do you mean just "on /off" or have you managed to automate the flow to keep the temperature constant ? - That sounds hard ! - PS I've asked this same question on another thread as well - so if you've already answered there, no need to bother here - thanks ]

I'm a little surprised that some of you are using the cooling water as a heater element - I run my cooling water much cooler than that - I'd be worried that if it gets too warm, I'd lose product vaour ! In fact I feel the output spigot from time to time and if it is warm, I turn up the water !

[Pikey]

i envy you lads who have room for this stuff.
would love to see the finished preheater if/ when you make it.

I have a couple of old hot water cylinders, at least one of which has a coil in it - so I'll be cutting them up to do the build as they have probably got lead based solder. - I will post pics, but expect them to be functional rather than things of beauty

[Swedish Pride]

function over form anytime.

[NZChris]

one and a half turns ? - so coiled through 180 degrees so it is facing towards the input - then another 180 degrees so it faces the same way it did originally and another 180 degrees so it is outputting on the same side it went in on - right ?

Wrong. One and a half turns has it exiting on the opposite side to the entry. 540 degrees.

[Pikey]

one and a half turns ? - so coiled through 180 degrees so it is facing towards the input - then another 180 degrees so it faces the same way it did originally and another 180 degrees so it is outputting on the same side it went in on - right ?

Wrong. One and a half turns has it exiting on the opposite side to the entry. 540 degrees.

Thanks - I was wondering whether to count the original staight as 180 or not - so yes I do - thanks again

[NZChris]

I was wondering whether to do it that way myself, in which case, the more heating could be worked into the preheater the better I would think.

Over-engineer it and it might not give you what you expect, but go ahead and try if you want.

Two Liebigs are better than one, especially if you are stripping to low abv low wines, which is what it is best suited for. Teeing the preheater condensate into the main condensate line adds to the abv at the spout so that the alcometer in the collection vessel will never reach your cut off point and you keep running until you realize you're an idiot.

[Pikey]

........... you keep running until you realize you're an idiot.

Oh I realised that many years ago Chris

I expect that by the time the wash is up to "boiling", the temperature differential between the vapour in the coil and the wash would be pretty minimal anyway and thus output would likely be small.

Bearing in mind your sensible advice on keeping the coils low, I'll make a decision when I see what I've got to work with, but 1.5 to 2.5 turns maximum I'm thinking atm.

[NZChris]

When mine is running to low wines below 30%, there is more alcohol coming off the preheater than from the main boiler. I haven't tried triple distilling where the aim is for 20% low wines and there would be a fair bit taken off by the preheater.

The French drawing doesn't show a coil at all. I've added one loop. I don't know how much benefit there would be from adding a second loop. There might even be a disadvantage.

[Pikey]

True Chris, but the french drwg shows a WIDE preheater which may approximate to the same thing.

I'm expecting the internal coil to be 1" copper when I expose it, so the contact area / volume would likely be smaller thn yours, but as I said "I'll make a decision when I see what I'm working with"

I'm really quite looking forward to this and have already started telling people I have a 25 litre electric still for sale !

[NZChris]

True Chris, but the french drwg shows a WIDE preheater which may approximate to the same thing.

You might be looking at a different drawing to the one I built mine from.

[Kareltje]

Looking for "Moonshine bible" resulted in several results.
Alaskan Bootleggers Bible
Complete Distillers Bible
Moonshine bible Facebook

We'll see which is usefull.

[Pikey]

Looking for "Moonshine bible" resulted in several results.
Alaskan Bootleggers Bible
Complete Distillers Bible
Moonshine bible Facebook

We'll see which is usefull.

Please do let us know if you find any good ones

I'd follow the approach Stillstirrin used in post #2 "Distillation of alcohol from farm products" - on free google books, it is probably the best bet - I just got caught and paid a few quid for a reprint of "Public domain" info.

i have many of the newer books, but I love the old stuff because they spent the time and effort in understanding to the best of their ability - didn't just compile a load of "Internet info" without thought and research

[SaltyStaves]

Hopefully this will be of some use.
https://youtu.be/3cVciMe6ZSo?t=85" onclick="window.open(this.href);return false;" rel="nofollow
The preheater is not discussed in the video (you don't even need sound).

Can see how it can be set to bypass or go through the preheater and converge back at the condenser, but I'd love to be able to see inside.
Would have to imagine there is some sort of coiling on the inside, as a straight 2" horizontal pipe doesn't seem too efficient.

The supposed reason why its in the middle of the preheater, is due to convection currents being undesirable as it upsets the wine (sounds like voodoo and would only apply to brandy).

[Pikey]

Thanks for that - "I'm not going to talk about THAT - it's not part of the distillation " - lol

We have speculated somewhat about what happens inside the "onion" - and here is the answer - from Hennessey - there's a brief "cutout" shot around minute 4 !

https://www.youtube.com/watch?v=as4k-eFpoyI