Bokakob 2" mini-still column

[Barney Fife]

Pik, I can pull well over a liter/hour(very close to 2 L/hr in fact) with my 2" Bok style head when running wide open in pot-still mode, and haven't run into the vacuum issue at all. What are the signs that make you believe this is happening?

[Pikluk]

in potstill mode you wouldn't since you collect everything that goes up.
but if you trying to get some reflux and the output siphon the reservoir you get no reflux.

with the thinking cap on i think i got a solution like a big T with one arm going higher then the valve.
gonna make it this weekend gonna take pics before and after.

What are the signs that make you believe this is happening?

collecting at 3-5 drop(rough approximation) a sec then start going at a continuous stream rate and temp jumping up.

[Barney Fife]

Okay, I see what you mean. I don't have that issue either; I can choke it down to a drop/sec and anywhere in between, and it's always behaved well. Just shows that each still is indeed a little different! I wonder if you don't have a slight restriction(solder, maybe?) right where your offtake tube is affixed to the column/angle plate? I made sure mine was very smooth and ground it down very flush before soldering the plate in place.

Yes, your idea of the T will act like the plumbing stack on our homes; yours just has to be a touch taller than your angle plate.

[Hawke]

As long as you put the vent after the valve it doesn't need to be that tall. On mine I used a compression 90* right after the valve with an 1/8" hole drilled in the top. (did have to straighten the tube between the column and valve a bit)

[absinthoman]

How long is the 2" head?

[schacht]

Two questions, one, how long in total are the coils and approximately how long was the 1/4" pipe used to make them? thanks!

[Hawke]

Most try for 8" length. I did a test with some tubing, took 1 foot of tube to make 1 inch of coil around a 1 inch mandrell.

[schacht]

Hi,
So I'm pretty new at this, I had a Nixon Stone and I took it all apart on friday and turned it into a bokakob mini with a double spiral + finger condenser. I only ran the nixon twice so I still don't really know what I'm doing when it comes to actual distilling. One problem I found with this bokakob design is that I changed from using a glass thermometer with a rubber gasket at the top of the column on my nixon to a thermocouple stuck in a 1/4" underneath the top plate in the bokakob. The thermocouple now heats up too much because it's touching the copper which is conducting a lot of heat, it stayed at a pretty consistant 81 the whole time exept for a few times where it moved a bit and showed 85 or so. Either that or it's just not a great thermocouple, it is from ikea after all. I think I'm going to find a way to use my glass thermometer.

Apart from the thermometer issue the still was running great I was probably only collecting 500ml/hour at 1000W so I think I could have turned it up a bit. Once I had collected about a litre and a half of distillate at 94% (I wasn't utilizing the whole column length for packing, I hadn't picked up enough copper scrubbies on friday afternoon) the distillate flow seemed to slow down, I tried turning it up but it wouldn't go up so I assumed there was something wrong with my needle valve and let it keep distilling. I measured the alcohol content a while later and it was only at 70%!! It clearly wasn't refluxing. Can somebody explain to me why there was barely anything being condensed later on in the run after not changing the heat or the cooling?

Another thing, I'm using prestige turbo pure 48 yeast and I only open the carboy once to put the clarifier in, but both times I've run my still the alcohol has a lot of banana ester in it. Is anyone else experiencing this?

Thanks a lot

[Hawke]

Bet if you get the rest of the column packed, the temp will drop and the ABV will increase.
A mini will run pretty rock-steady until it hits the tails. If mine climbs by 0.2*C, I switch to a tails jar.

[schacht]

I've got about 40 inches packed there's only maybe 8 left. I think the thermometer reading was just wrong because my nixon with less packing gave me rock solid 78-79 with a proper thermometer.

I'm more worried about the fact that nothing was really coming out and it wasn't refluxing at all near the end. does that just happen when the ethanol is running low in the pot? that wouldn't really make sense to me.

[Hawke]

Mine slows considerably toward the end and the hydrometer almost jumps out of the parrot.

[tracker0945]

I'm more worried about the fact that nothing was really coming out and it wasn't refluxing at all near the end. does that just happen when the ethanol is running low in the pot? that wouldn't really make sense to me.

Only thing I can think of is that you did not have enough heat in the pot.
You should be able to collect condensed vapour with only plain water in the pot. The column temp at this stage should read 100C or 212F


Cheers.

[Northern1]

Which Bokakob plan set did you use for this unit?
I'm considering building one in the next few months, but was trying to decide what one would be the best balance in performance vs construction complexity.

[fred45]

What is the angle of the slant plates and is there a new template around for them/
THanks

[Hawke]

Plates should be 30 to 35 degrees. With 3/8 to 1/2" gap between them.
Haven't seen any new templates.

[Freedave]

fred,

do you really need templates? cut the slots, slide the metal in and trace a line with a marker, cut them out, solder them in and file/sand till smooth.

[rabbit_]

Woo.

Just got all my copper sorted and torch + solder.

I'm using 65mm for the Piping and 9.5mm for the condenser.

I'm just looking for a needle valve (I've got some prices, they're all pretty pricey though...) So I wondering, has anyone had any luck with ball valves, they're much cheaper but I take it they wouldn't be as precise to control...

I'm looking at having a screw base on the boiler so I can screw all my pipes together (make it easier to pot still etc..) Will the reflux condenser work well for pot stilling, or should I just make a new potstill fitting....I've enough copper (4.5m of 65mm and 15. of the 9.5mm...)

Should be fun!

[Pikluk]

quick update while i have some net...
this is a nice easy to use design easy to make
does some really decent booze.
made a bunch of neutral with it also lot more "whiskey" and some nice rum.
those last 2 made in pot still mode with the 8 inch column...

[fatbloke]

A very interesting thread, with lots of info.....

I was still wondering where the threaded copper adapters/joiners came from, or what they were originally designed for..... so I could look see if I could obtain some locally (UK).......

I'm still researching the possibilities of making something like this, though the copper parts are either expensive or just hard to get......

thanks for the info and guidance...

regards

fatbloke

[Pikluk]

anyone got pic of a "oz" version
you know whit brass fitting or something...
im only asking because i got a few people asking where to get those copper fitting.
i from Quebec i got them from the local home depot.
from my understanding in australia or new zealand you cant get those
i can buy and send you those but the shipping is a killer like more then the part itself...
....
so you kiwi and ozzy can keep drooling just kidding...

[HookLine]

Hi Pikluk, how's things?

One small detail, Australia uses BSP threads fittings for most stuff. North America uses NPT for most stuff. Can you get BSP fittings, or only NPT?

And I think some here would be prepared to pay the freight cost for those threaded copper fittings. We only have to do it once (for each person).

Hook

[adama_bill]

We only have to do it once (for each person).

+1

[Pikluk]

im doing good thanks for asking, you ?
why would you want any 2" copper fitting with your super shiny stainless still?

i probably only can get the "regular kind" but if you get both
male and female part it's not really important does it?

[HookLine]

im doing good thanks for asking, you ?

Hanging in there.

why would you want any 2" copper fitting with your super shiny stainless still?

Not for my reflux column really. But I am going to do another pot still one day, and they could be very useful for that. Also good for for Liebig connections.

i probably only can get the "regular kind" but if you get both
male and female part it's not really important does it?

This is true.

Thanks.

[Putittogether]

What is the total height of the still? I see the 2" but it appears much larger when all parts are taken into consideration. PS I am a complete noob.

[bstinga]

What is the total height of the still? I see the 2" but it appears much larger when all parts are taken into consideration. PS I am a complete noob.

rad14701 wrote:
For a 2" column 64" is at the upper theoretical limit, but should work at that height... With a height:diameter ratio range of 12:1 to 30:1 some members are having good luck with 36" columns while others are using 48" - 60"... You can always cut it shorter than 64" but you can't cut it any longer... Remember, it's the packed column portion below the slant plates where all the magic happens...

source: http://homedistiller.org/forum/viewtopi ... o#p6803647

Plus whatever height your boiler is. However with this design you can start from as little as a 1 foot packed column and run it at 750w to 1kw and produce superior product to any "off the shelf" still IMO (If height is an issue).

P.S. in NZ and probably OZ imperial copper parts and fittings can be found at specialist refrigeration parts supply stores as all refrigeration and hospital O2 supply lines etc are standardised to these units. I will have to have a look if they have threaded unions next time I visit a supplier - not sure?

[piratesteve]

does one have to use a condensor on the outtake arm?? or will the condensor in the head be sufficient????

[rad14701]

does one have to use a condensor on the outtake arm?? or will the condensor in the head be sufficient????

You need both... From the sounds of your questions it is apparent that you need to do a bit more research regarding distillation theory as well as the theory surrounding the various types of stills...

We're willing to help you along but we won't spoon feed... The bulk of the research is up to you... We've all had to do it so nobody is singling you out here... During you research you're going to get answers to questions you haven't even thought of yet...


<spoon-feed>
The reflux condenser cools the vapor and sends it back down into the packed column where it gets re-distilled thus adding purity... The take off or product condenser cools either the liquid or vapor that enters the take off branch, depending on still type...
</spoon-feed>

[HookLine]

You do not need the small condenser on the output. Plenty do not use it. But it can be useful, especially if you want to take alcometer readings straight away.

[piratesteve]

thnaks for the information. I was pretty sure. I was just kind of double checking that i had this theory down right. Thanks for the feedback... Is greatly appreciated.