Junkahol Brew Day

[Anavrin]

I'm running my boka for the first time, it's got 22 litres of wash at 11% ish, I've got no packing in but column cooling on full so it's just a strip to start with



It's still warming up at the moment, switched the boiler on at 5pm

[Anavrin]

The temp in the column seemed to shoot up from 40°c to 85°c in a matter of seconds! I've now turned down the power to the boiler, and the temp probes reading a stable 84°c and I've got a constant dripping, the first 100ml measured 84% before I tipped it away

[Anavrin]

I'm well on my way now, I've collected three 300ml jars and two 400ml jars so far, the temp on my probe has become stable at 89°c for a while now, not sure if it's picking up heat from the column, I suspect it is and that's why it's reason higher than expected, here's a pic of the collections so far showing the alc % on each bottle.




This is certainly more fun than all grain beer, especially as it's a home made boka

[Anavrin]

I'm starting to wonder if my reading are correct, I'm now onto my 10th bottle, I've not measured it yet but my 9th was at 59%

It's coming out slow now but I'm thinking how can I be pulling such high ABV with no packing in the column??

Is it the fact that it's a boka and not a pot still?

Also it's coming out cold due to the lebig

[Anavrin]

9:45pm finished, here's my cuts
1, 300ml @81%
2, 300ml @77%
3, 300ml @75%
4, 400ml @74%
5, 400ml @72%
6, 400ml @70%
7, 400ml @68%
8, 400ml @63%
9, 400ml @59%
10, 300ml @53%
11, 300ml @40%

It took ages to finish the last few bottles, maybe I pushed it too far, I was expecting to get down to 20% after reading several posts over the last few weeks, maybe that only applies to pot stills as I took 3.9 litres off this wash!

Any ideas anyone?

[YHB]

CONGRATULATIONS!!

The temp in the column seemed to shoot up from 40°c to 85°c in a matter of seconds!

You are measuring vapour not liquid, one second there is no vapour, then the wash boils and there is lots of vapour to measures. Think boiling a kettle, switch it on and you can hold your finger over the spout, one second later when it boils, try the same manouver and it hurts. Boiling a wash is no different, if you want to see gradual rise you need to measure the liquid in the boiler.

If you are getting these numbers you do not need a thumper they bode well for the future when you add the packing.

I think that I agree with you, From the temperatures it looks like you are getting some reflux, perhaps your slant plates are not catching all of the condensate and allowing some of it to travell down the side of the column?

When you quote temperatures you only quote degrees, is that because thats all your thermometer gives, or does your thermometer give you decimals of a degree but you are bored and do not type them?

I ask because I tried working a Bok with whole degrees and it was not a success, you definatly need to be able to read 0.1 of degree. The difference between hearts and tails is only 0.2, I have been sat there thinking I am pulling lovely hearts butin reality grotty tails.

You are on the way - best of luck for the future, and have a great holiday.

Brian

[Voddy]

YHB, you and your ilk are amazing. Thanks for your continued help and efforts here. ;-) I love to read your posts; I wish you were my neighbour!

[Anavrin]

+ 1 on the above, although I like my neighbours the way they are, one of them just brought these for the kids

[Anavrin]

Just done a run with the 6mm raschig rings packing, I put 1.8 kg of them in the column, I previously filled the column before I soldered it all together and it took 2kg to fill it up.

So I poured all my bottles I collected the other day into about 18litres of water and fired it up, it seemed to stabilise at about 84°c after I turned the power down, the first 300ml come out at 90%
Which I was quite happy with but the next 300ml was only 78%, seems I'd took my eye off the ball a little and the temp had creeped up to 88°c

I decided to lower the power until it was just coming out a few drops a second, seemed to be coming out painfully slow but I stuck with it and it measured 88%

Just for the hell of it I then cranked up the power to collect the next lot and as suspected it was much lower at 68%

I'm thinking around 90% might be the max I can achieve with the packing I'm using.

Got a feeling it would take quite a while to collect a full run at a high percentage, it's certainly proving more complicated in reality than it first seemed when all I was doing was reading about it.

[YHB]

This is the way I do it, others may have better ways, its up to you to find your way.

Full reflux maybe 1.0 kw for 30 minutes, or untill the temperature has not changed for 5 minutes, We are talking about it not changing by 0.1 degrees.

Take off the fores at 1 drip per second.

Take the heads off at 2 drips per second-yes it is slow but speed it up an you will be throwing good stuff down the toilet.

When you are into the hearts you can speed up the take off, but the temperature should remain stable, if it goes up by over 0.2degree, close the valve and let it stabilise again and try taking off the output more slowly until you find the rate that suits your rig. You should at this point be able to increase the power slightly which will increase the reflux ratio which will improve the quality.

Try and take it too quickly with the temperature rising slowly will give you a bottle of spirits smeared with tails.

When you get to the point that you cannot hold the temperature you will probably be well into the tails.

I have deliberatly not mentioned temperatures as they will be totally different on your rig to mine insulating the column will help and cold draughts will not.

Running a bok can be a bit tedious and frustrating at first but once you find the power levels and take off speeds that suit you then you will be able to dial them in quite quickly,

Until you get the results you want keep notes with regards to take off and temperature, once you do then find some good music and take a good book into the shed.

If you will allow me one observation, the tube to your valve is very long. If the temperature spikes and you start pulling tails, close the valve re stabilise, but then you are stuck with a tube full of tails that you need to get rid of, the shorter the tube the smaller the problem. This problem will go away when you get your take off / power rates sorted.

[Easydrinker]

I will be honest and state that I occasionally read the the posts of you Boka//Reflux/Fractionating still type of people with envy,at the idea of azeotrope,or at least something stronger than my humble pot produces.
I guess one day I may try to build and follow the dark path,simply because I can.
For the most part, a pot,cuts and a carbon filter produce the neutral that I desire.
And it seems so easy and formulaic now,why would I wish to complicate things?
But I will see you on the dark side,- when life gets boring.
Just because I can.
Robert.

[YHB]

I have had a look through your posts and spotted another potential issue, the good news is that the fix should be relatively straight forward and will help with the long take take-off and associated smearing at the same time.

The tab on the bottom slant plate is supposed to encourage the distillate to run down the middle of the column, your,s is doing the opposite. The tab is higher than the top edge of the slant plate making the liquid run over the sides of the plate and dribble down the underside / walls of the column.

You missed out two important saw cuts that would make the tab bend below the top of the plate making a small weir for the distillate to run over and down the tab.

I have a very similar set up to this on my Bok, it works for me.



The theory being that when you close the valve, the distillate will continue to flow and wash out any tails left in the tube. So that when you open the valve again you have hearts.

The return tube at the bottom will ensure that the reflux distillate will be returned to the centre of the column for maximum effect.

Cool Eh?

[Anavrin]

Thanks for the info Brian, im already planning in my head how im gonna butcher my column for some modifications, Easydrinker puts it nicely calling it a dark path, it certainly is a dark art getting the most out of a self built boka, I have had several thoughts lately along the lines of

"why did I not just buy a T500?"

However im determind to improve on it and I've learnt so much more having a go and building one than I would have otherwise.

I'm going to split the column so I can detact the cooling section, at the same time modify the plates and add a return pipe as suggested.

My main concern is the controling the vapor temp by only varing the power to the heatng element, I feel I need a finer control mechanisum so the main modification im thinking of is to install some cooling in the main column, similar to the T500 I will have a few coils inside the top of the column with an internal pipe coming part way down and out the side, some sort of VM/LM hybrid!

[RumJohn]

@Anavrin: Your on the right track. One thing you might consider is insulating your column - it will help prevent cold spots that will cause turbulence. I let things equilibrate for an hour and then take off very slowly so as not to disrupt equilibration. Your temp will settle and stay constant while the good stuff comes off. As soon as it starts to climb - time to change collection containers.

There is no reason to gunk up your equipment on a beer stripping run by having packing in.

@EasyD: I am thinking of quitting the vodka and gin. If I do I will use my column as a pot still. Most of my sales are rum and cachaca. Apple Pie included in the rum.

But too hot here at the moment to do anything so my new project, "Gunfire Breakfast" (look it up) is on hold.

[YHB]

"why did I not just buy a T500?

That does not sound like much fun.

im already planning in my head how im gonna butcher my column

Don't do that - learn how to run the LM before you make any changes, having more things to fiddle with will just make things worse. You have just built a lovely still that will serve you well, you just need to understand how it works.

My main concern is the controling the vapor temp by only varing the power !

Hear we go,

You can not controll the temperature of the still by alterIng the power level and adding the additional cooling that you describe will really screw things up - I promise.

Basic physics.

The temperature of the vapour leaving the boiler is directly proportional to the alcohol content of the wash. As the run progresses the temperature rises because the alcohol content decreases not because you have turned up the power. If the boiler was filled with water the temperture of the steam would be 100 deg, turning up the power would only give you more steam at 100 deg. Turning the power up and down only increases the amount of vapour, not the temperature of it.

So the temperature of the vapour leaving the still is fixed and altering the power or adding more cooling does not help, what will?

The BOK is a liquid management (LM) still and is only controlled by the amount of liquid you take off.

When the boiler is doing what its supposed to be doing, i.e. boiling the column is also doing what it is supposed to be doing i.e. -refluxing.

The reflux action will cause the different elements of the wash to stack up with the lowest temperature vapour at the top and the hottest at the bottom. There are many compounds in the wash but for this description we will only call them heads and hearts.

After leaving the still equalise for half an hour or so you will have some heads at the top, hearts at the bottom and a mixture in between that have not got themselves sorted out yet.

The liquid in the take-off system will be a condensed version of the vapour at the top of the column in this case heads. The temperature on the thermometer will be the temperature of boiling heads.

If you open the valve slowly - 1 drip per second - the reflux column will have time to isolate more of the heads at the top of the column before the hearts work their way up the column to the valve. If you remove the liquid too quickly then the column will not have time to isolate more heads and a mixture of heads and hearts will reach the top. You will then be measuring the boiling point of a different vapour and not an increase in the temperature of the same vapour.

You will soon establish how much liquid you can take off and maintain equilibrium, i.e. when the take off rate is less than the amount of vapour that the column can reflux.

My belief is, keep the power level low, turning it up increases the activity in the column and disturbs the stacked vapours.

That's enough for now. I will start another thread - "how to drive a BOK" it is a question that gets asked very frequently.