Bokakob Still Question

[mistergrieves]

So I have finished my noisily still but have a general question about the runoff pipe. Many plans don't seem to use a condenser coil, but some have a condenser colar. I know that you want to minimize pressure for the output. Does anybody have any opinions on this. I was considering coiling the output tube and running it through an ice bath on it's descent to the collection container.

[Bull Rider]

I've never driven a Boka, but I think you'll find that a lot of users have a small leibeg (condenser) on the outflow. Just enough to knock some of the heat out of the product as it exits the column.

After I finish my second pot still I'd like to build a Boka.

Bull.

[aqua vitae]

I have a still where the product is already condensed in the still, but still hot, similar to LM columns.
I use ambient cooling. A 2 meter long 10 mm copper pipe in spiral cools it to near room temperature at my output ratios, around 1 litre/hour.
Just be sure the spiral is leaning down at all times.

[Braz]

I have a small liebig jacket condenser on my takeoff tube. The water runs through the liebig then to the main condenser coil. My product comes off at around 60F which is perfect for getting accurate ABV readings from an alcometer in a parrot.

[NcHooch]

A bok will typically output distillate at close to 72c since the collection pool is right in the vapor path ... It's a good idea to chill it before it hits the collection jar.
I haven't really seen anyone else use a air-cooled coil to chill the distillate (other than me ) but i works perfectly fine. it's room temp by the time it gets to the bottom. There's usually a 8 inch extension attach to the end to give it a little reach away from the boiler..



Hope that helps,
NChooch

[aqua vitae]

I haven't really seen anyone else use a air-cooled coil to chill the distillate (other than me )

Read two posts up...

[Braz]

That's pretty, Mr. Hooch.

[mistergrieves]

Awesome. Appreciate all the help. Anyone have any thoughts on where to place the thermometer? 1.5 inch is a pretty small column. Was thinking between the 2 slant plates. Different designs seem to have different approaches.

[Braz]

Awesome. Appreciate all the help. Anyone have any thoughts on where to place the thermometer? 1.5 inch is a pretty small column. Was thinking between the 2 slant plates. Different designs seem to have different approaches.

Yes, between the plates. Specifically, under the top plate so the tip of the thermo probe will read the rising vapor temp but be protected from the returning cooler liquid. Vapor temp is the one you are interested in. On my avatar you can see the thermo tube on the left side of the column sticking up at about a 30* angle. Pay no attention to the big dial thermo. It is mostly there for effect but it does seem to read returning reflux temp, or some average of vapor and liquid temp. During a run it reads 12-15F lower than the other thermo.

[axle1960]

Awesome. Appreciate all the help. Anyone have any thoughts on where to place the thermometer? 1.5 inch is a pretty small column. Was thinking between the 2 slant plates. Different designs seem to have different approaches.

I placed my temp probe in a thermo well just below the bottom plate. It is in a tube that protects it from the falling liquid.
My Boka is a 3" SS with the plates set at 25 degrees and 3/4" apart, I have 18 SS scrubbers in 48" of packed column.
This configuration works very well.

Axle

[Caprimulgus]

It is in a tube that protects it from the falling liquid.

Wouldn't that result in a cooled thermo well?

[axle1960]

It is in a tube that protects it from the falling liquid.

Wouldn't that result in a cooled thermo well?

Not really. I control my cooling water so as to just condense the vapor and no more then that. A reflux tower is most efficient if the returning liquid is not "super cooled" and is re-vaporized in the upper part of the column, this is necessary to maintain a well balanced and equalized still. My product is quite hot coming out (I need a product condenser/cooler).
I'm using a digital thermometer that does not display less then whole numbers, so I use it in the Fahrenheit scale as this gives me a finer scale. It does have an adjustable alarm that is handy.
With my setup, the still will reach equilibrium and settle in at 171 F, this is where I start to draw off foreshots at a slow rate. When the temp raises to 172 F, I am into the heads ( I continue to collect "foreshots" until I have 60ml ).
I draw the heads at a slightly faster rate until the temp raises to 173 F, smell and taste confirm that the hearts are starting. I draw an extra 10ml just to be sure.
When the temp goes up to 174F, the tails are starting. I use a parrot so I have inadequate time to change to my tails collection.

My last run was a triple batch of simple sugar wash that I stripped out first in 3 separate runs down to < 20%. I had about 22 L of stripped wash. To this I added; a little more then 4L of feints and several bottles of spiced rum that I wasn't happy with. I added water to bring all this down to 40%.
It took 40 minutes to reach temp and I turned the heat down and let it equalize for an additional 20 minutes before starting to slowly collect foreshots. I collected heads until slightly beyond the next temp increase, smell and taste confirmed that I was into the hearts.
I Do Not use my parrot when collecting fores and heads.
I collected a little beyond the first temp increase for a total of 220ml of foreshots, then started collecting heads.
The next 4.5 hours gave me slightly less then 7 - "60's" (1.75ltr bottles) that should average 94 to 95% with temp correction. I had to fiddle with the collection rate a little towards the end of the run, even putting it back into full reflux for 10 minutes and then collecting at a reduced rate.
When I could no longer control the temp at 173F, I opened it up and collected the rest as tails, down to 20%. This only took about 20 minutes and yielded about 600ml.
I was very happy with that run. I'm going to continue do do stripping runs first and then spirit runs after.
Right now I've got a batch of DWWG that has been doing it's thing for a week and hasn't stopped yet. I'm looking forward to running this before doing a triple batch molasses wash.
I hope this is of some help and that you could find some useful info in my ramblings.

Axle

[Caprimulgus]

Ramblings can be both fun and informative

[axle1960]

Ramblings can be both fun and informative

Yes indeed. I feel better for doing it.

[exon]

Those are good driving instructions, Axle.
Tnx!
exon

how big is your kettle ?

[axle1960]

Those are good driving instructions, Axle.
Tnx!
exon

how big is your kettle ?

I have a 55 ltr keg with a 4" opening. I made a 6.5" SS flange from 1/4" plate, uses 6 SS bolts and a cork gasket.

Axle

[exon]

Wow!

4" ho !!!
GREAT takeoff capability!

U need a bigger pot!
exon

[axle1960]

Actually, I have been keeping an eye open for a bigger boiler. I haven't found anything yet but I can afford to wait. The setup that I have now works great. I used to be able to over drive my 2" LM column but not the 3" Boka. The 2" (rashing rings) would give me 95+ % but it was slow, the 3" (scrubbers) gives me 94 % at about double the speed. I might be getting some channeling in the 3", I will be adding some centering collars soon. I love playing around with this stuff.

Axle