SS super reflux weirdness.............

[Phantom]

Been digging through my stock of wines and meads that I've made to work out what's good enough to be a "keeper" and what's gonna go through the still to add to my "mixed fruit" brandy attempt (very amateurish, just distilling "it" off and then putting it into a large carboy with some oak flavouring and toasted oak chips).
Anyway, I finally got an internal water supply going for the condenser (instead of messing around with running a garden hose around, leaks, etc etc).
So, this morning, I've put 5 gallons (of mead/fruit wine) in the still and got it running. I'm using "rings" in the reflux chamber instead of saddles (as usual). I went to check the still and noticed that it was running at about 1 drip per second, but the thermometer was showing 81 degrees C - so I've increaded the water flow a bit and it's now sitting at a constant 79 degrees C, which in theory, is correct.
But now the damn thing has stopped running any spirit out. So far it's given me about 1 litre at 85% ABV, which would be about right, so I'm wondering that if the thermometer is showing the "proper" temperature, why the hell it's not running spirit ??
It's a standard glass thermometer, so I'm not entirely sure whether there's an accuracy tolerance for it i.e. if it's accurate to plus or minus 1 degree (or something like that), it could be showing 79 but actually be at 78, and hence it needs to heat up a little bit again.......
Or has anyone tried one of these stills, but used a digital thermometer instead of the glass one ?
As it wouldn't be too difficult to use a digital one and just use something that packs the hole in the thermometer bung - which I'm thinking might give a greater accuracy for operating temperature
what d'ya reckon ??
regards
P

[Opus 27]

Hi Phantom,

Couple of points I would make, but bare in mind I\'m still on the learnining curve.

Firstly increaseing the water flow may well be increasing the reflux rate to near 100% reflux i.e no output every thing going back into the the boiler. Secondly I am still trying to determine the correct level for Rashig Rings/Packing to get the most efficient reflux going. Some degree of logic would suggest that this shouldn\'t go above the cooling colar in order to cause condensation and hence reflux. This positioning would also affect temperature readings. As for digital thermometers I was fortunate enough that we already had a particularly good hand held \"K\" Type so I just had to get a suitable probe to fit the existing bung. The thermometer and probe both came from Farnell in the UK. Ours was quit expensive but it is used for other purposes and there are cheaper suitable variants. Finaly it was these kind of issues that prompted me to look at heating which I\'ve posted in another thread (SS Reflux Mod)

Hope some of this makes sense.
Regards Opus

[bluecap]

Hi Phantom

I use a digital thermometer; it is less accurate than the glass type. I put the ends in a pan of boiling water the glass one read 100 which was spot on the digital read 99, I did the same with some warm water and it still read 1 degree down so I just compensated this when running the still I have it set to 83c at which the alarm goes of and I know to adjust the water, my only reason for using it. To fit it in the bung I use the pointy bit of an old pen case put the pointer through the pen and fit the pen in the bung.
As for your distilling are you sure you worked out the alcohol level right in the wash seeing as you was using bits and bats?

[umpa]

How can you be sure the glass one is correct. Water boils at different temps depending on the air pressure. It only boils at 100 oC at sea level.

[bluecap]

Good point umpa, I tried it with a second digital thermometer and it also read 99c so it is probably right.

[umpa]

yeah, i have a youngs beer making glass one that reads 110oc at boiling point.

[Phantom]

Well this is where I get some weirdness, as I\'ve started it again today with another batch of meads/wines (nearly finished, only a 2.25 ltr DJ to go but I\'ll probably use the table top still for that....)
Now the last time I did a batch like this, the glass thermometer sat perfectly at 79C, whereas this time, I\'m using a \"pocket\" digital thermometer (adapted to fit the bung with PTFE tape), yet with the tap wide open, it\'s been consistently measuring 81.6C, so I\'m wondering if it\'s me and kit that\'s not quite as accurate as it could be, or whether it\'s a mains pressure fluctuation.....
I\'m not overly fussed, as it\'s just recovering alcohol from wines/meads that would otherwise go down the drain - but it\'s handy to keep it (the alcohol), as it can just go into my large carboy to be used as a \"mixed fruit\" brandy (it\'s got some oak extract and about 5 packs of heavy toasted oak chips in it for \"barrel simulation\"), and then that in turn can either be drunk or used for fortifying wines/meads that either need a boost or just to top off after racking.
A little annoying really as it\'d be nice to have a thermometer that can be trusted as plus or minus whatever, to be able to know roughly where I stand.
As for knowing the strength of the still content being distilled ?
As far as I understand it, the theory of following the instructions i.e. filling the reflux chamber to just below the crossover pipe and then having the end of the thermometer sitting in line with the crossover pipe, should, allowing for the fact that the heater isn\'t adjustable/controllable, give a consistent strength of output, the only difference being that with a varying strength of charge for the still, would give a different total amount of distillate.
Perhaps it\'s just me being anal about it and trying to get too accurate a level of strength/purity from kit which is basically, well, basic.
I don\'t know.
As I say, I\'m not overly fussed, as it would be better to have a bit of other alcohols, and esters etc in the distillate to make it closer to \"proper\" brandy.
As for expecting different results allowing for altitude, well that\'s not an issue as I can categorically state that if anything, I\'d be at no more than 5 metres above the average sea level...so as long as the hardware is reasonably accurate, then when I finally remember to test the thermometers, they should give me 100C on a water boil.....
I\'m gonna have a bit of a check (again) next time I do a batch of wash though, as Opus points out, there\'s little gained in having a level of rings above the cooling collar, plus it give a little more leeway with where the end of the thermometer is positioned.
Ha! just to confuse matters more, the last couple of batches of wash have been run with either no rings in the chamber, or just a few and with the reflux chamber water jacket part disconnected from the water, so it\'s running in \"pot still mode\". When I\'ve got the last of my wines/meads done, then I\'ll be running it with copper mesh, not rings (the first stage distillate will be let down to 40%). So that then brings in the issue of how tightly to pack the copper mesh. Last time I tried it, it must have been refluxing quite a lot, as it took about 11 hours to run a batch.
Confusion, confusion.........

[Phantom]

Well it\'s been running since I posted the above, but it\'s still only managed to output about 1 litre. So I\'m wondering if it\'s refluxing too much - if there is such a thing, and whether something as basic as a SS super reflux could work in such a way.......
Very curious.................

[Opus 27]

At the moment I would guess we have two or perhaps three threads going that are all inter-connected one way or another. Ok Phantom on your one point of trying copper mesh I tried stainless steelmesh which was a desaster but I think I over stuffed it. The other issue I have is trying to get the same results from identical washes. This is why I'm playing with my idea in the "Super Reflux Mod" thread. I'm about to start a 40L sugar wash using Bakers Yeast which I will run as two 20L batches when it's ready. If my method of temperature control works then the same settings should produce identical results for both batches. Having said all this I think in some ways we're trying to make a silk purse out of a sows ear by expecting more from the still than the manufacturers intended. Therefore the next project is going to be a decent reflux head. As I'm fortunate to have TIG facilities we're looking at sourcing suitable stainless steel tube but I'll post on that as and when it happens. And Phantom your request in the other thread is in hand.
Regards Opus

[Phantom]

Cheers Opus, any additional info is much appreciated.
Additionally to my last post here, I went and turned the water to the condenser down a little.
Yes there was a subsequent increase in temperature (to about 81.6 C) but there was also an increase in the output speed (about 2mls per seconds), so I\'m guessing that the water must have been causing too much reflux in the chamber.
The last test quantity I took was measuring up at 86% ABV. So I finally switched it off when the thermometer showed abou 88C. I figured that just about all the alcohol was out, that could be reasonably used (got about 3750mls in total).