Stalling distillation

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Kiwi_phil
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Stalling distillation

Post by Kiwi_phil » Wed Feb 15, 2017 12:47 am

Hi guys, need some help here. I ferment a birdwatchers in a 100 litre batch, I then rack it off into my boiler, with a 3kw element, and a 65mm boka column. It takes about 3 hours to get started, then cranks out beautiful 95% spirit at a healthy rate (I drop to 2kw for the run) after I've taken 7 or 8 litres of this, it slows down to a stop, even with the full 3kw again. Measured just before it stopped it was still coming out at 85%. My column is insulated, the boiler is not (it was a 35 degree day and the still is in the sun) it's done this twice now, (I've just gone from gas heating a 50 litre keg) and while the product is beautifully clean, I am afraid I'm tipping good wash down the drain. Do I need more power? Really looking forward to hearing what you legends reckon.
Thanks for your help
Phil
(I'm going to have a drink and eagerly await your replies)

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der wo
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Re: Stalling distillation

Post by der wo » Wed Feb 15, 2017 2:28 am

Although 100% open valve you got no distillate?
What abv had the wash?
At 7-8l 95% from a 100l bw single run, I think you have reached tails. I would double distill a bw.
Why do you allow 85%? Close the valve and rise it again to 95%.
65mm will run better at 3kW than 2kW IMO.
In this way, imperialism brings catastrophe as a mode of existence back from the periphery of capitalist development to its point of departure. - Rosa Luxemburg

rad14701
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Re: Stalling distillation

Post by rad14701 » Wed Feb 15, 2017 7:03 am

If your reflux column is running efficiently there will be very little alcohol left in the boiler once take off slows...

Here is a trick I have used many times when I wasn't exactly sure what the beginning %ABV of the boiler charge was when mixing remaining random wash and feints for a reflux run... Open the take of valve all the way so you are as close to pot still running as possible and monitor the temperature... If it creeps up near 204F, you're as good as done... My LM reflux column gets unstable as it gets close to the tails and the temperature climbs to 174F and then rapidly proceeds to about 180F... If I open the take off the column temperature will end up in the 204F range and I sometimes collect tails in that mode right up to 208F... But the amount of extra spirits isn't really worth chasing after as those tails are so pungent... Better to just stop collecting and call it a day... Even in reflux mode there is no need collecting beyond 180F as you're into extremely late tails at that point - if your reflux column will even produce anything at that high of a temperature...

Kiwi_phil
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Re: Stalling distillation

Post by Kiwi_phil » Wed Feb 15, 2017 2:59 pm

I only ever shut the tap at the start, it's normally wide open for the entire run. When this column was on my 50 litre keg with the gas burner it would just keep distilling right through the tails till it was just stinky water, but this boiler stops. I understand I'm probably beating the time to stop taking, but I at least want to be able to collect further for the next run instead of tipping down the drain. I've never experienced a still stopping before. Is this normal? Has it just not got enough power to push the higher boiling point stuff up the spout? Should I chuck another couple of kw in there?
Thanks again guys.

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still_stirrin
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Re: Stalling distillation

Post by still_stirrin » Wed Feb 15, 2017 3:11 pm

Kiwi_phil wrote:I've never experienced a still stopping before. Is this normal?
My VM reflux head will. It produces at a high %ABV all the way to "the end". The output virtually stops. I can adjust the power to put more heat into it, just to scrub the tails. Usually, there isn't much more in the boiler by the time it stops producing. The output proof will drop like a brick.
Kiwi_phil wrote:Has it just not got enough power to push the higher boiling point stuff up the spout? Should I chuck another couple of kw in there?
Go ahead...whatcha' 'fraid of?

Climb on that pony and show it who's boss!
ss
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Kiwi_phil
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Re: Stalling distillation

Post by Kiwi_phil » Wed Feb 15, 2017 3:43 pm

[/quote]Go ahead...whatcha' 'fraid of?

Climb on that pony and show it who's boss!
ss[/quote]

Haha, I'm afraid of having to go and buy a bottle of argon to set up my tig and weld on a new element thread.

Sounds like I should just forget the miniscule amount left over, appreciate my still is running like a dream, and even stops the take unsupervised, and keep on shinin' ;)

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