Tips for running bok-mini in potstill mode

[digitalhippie]

So I built a bok-mini using 3' of 2" pipe for the column. Works great in reflux mode... made 5gals of turbo yeast / sugar wash for testing and everything went pretty smooth.

Now I have a batch of molasses wash that will be ready to make into rum this week. Looking for tips on how to run the bok-mini in potstill mode. Obviously I need to remove the packing material... but any other tips? Should I run with the valve all the way open the whole time (0 reflux)? Tips on where to make cuts? TIA

[rad14701]

Pull out the packing and run with the valve wide open for pot still mode...If you still get unwanted reflux you can insulate the column and/or remove the needle valve... Cuts would be made like any other pot still...

[digitalhippie]

Would it help any to close the valve and let it reach equilibrium before letting off the foreshots? Or just run the valve open the whole time?

[rad14701]

You won't really be able to reach equilibrium without scrubbers, but you can try pulling foreshots... I've done it with my rig...

[digitalhippie]

Well I guess I'm getting unwanted reflux.... first attempt was too pure with little to no flavor.

[Husker]

Insulate, insulate, insulate. Also, be SURE your takeoff valve can handle the flow, and does not return anything back down the column, and also, do NOT try to run slow. Run at a nice steady boil.

If you are able to get your column hot enough (and keep it that way with insulation), then ideally, there should be little reflux at all. The tube should simply be like an extension of the boiler (if it gets hot enough).

There is SOME reflux you can never get away from. That is the bottom slant plate. It WILL be cold enough to condense some vapor, which will fall. Also, the bottom edge of the top plate will also be cold enough to condense. This in of itself, is probably equivalent to another 'plate' (possibly even more). Thus, it is likely the best you will ever get with a bok, is the same as a 2 plate design.

When I started distilling, the first still I built was an offset head. I was able to replicate a pot still pretty well, by running hard, not having ANY reflux, and insulating the column AND the cross over tube WELL. 100% of the vapor was condensed and removed (my valve could easily handle the flow). When I built the still, I built it with a removable column (boiler had a connector, the still head had a connector, and the column had a male connector on one end, and a female on the other). In running, with or without the column (if it was WELL insulated), did not make a huge difference in the ABV% of the output. I even could put 3 scrubbers under the return, and run slow at the start, and bleed off and pretty much compress the heads, and then open up the output 100%, and start right out in hearts, getting a larger hearts cut than 'normal'. I still do not have a bok inline (but may build one this spring), so I really do NOT have practical experience running one as a stripper or pot still. It is possible that a boka might not be an 'ideal' type still in this situation.

Question: How much of a gap do you have between your plates? It it is pretty tight (say 1/4"), then that will make it all the harder for vapor to pass without condensing.

H.

[digitalhippie]

I added some foam pipe insulation and did a second run. Still pretty colorless/flavorless.... towards the tails some of the color came thru on this run. Guess the only other thing I can do is remove the valve...

[Husker]

Note, when distilling, the output is ALWAYS clear. Color (and much of the 'finished' flavor), comes from the aging process.

H.

[digitalhippie]

Good to know. I guess I was expecting more of the color to come thru in potstill mode....

[olddog]

Whiskey, Bourbon and Rum etc all come of the still clear, the color comes from oaking.

[digitalhippie]

So... in the case of rum, you're saying the color/flavor comes from oak and carmalized sugar that are added after distillation?

If that's the case... why bother with fancy washes (fruits, grains, etc)? Sounds like white sugar / turbo wash is the best bet... then you age/flavor as needed after distillation.

[digitalhippie]

Sorry if it's a newbie observation... but... I am a newbie to the hobby lol

[digitalhippie]

Oh and to answer your previous questions...

my plates are about 1.25" apart (height between them)

and I typically run the heat so that the water out of the condenser is just barely warm....

[olddog]

If that's the case... why bother with fancy washes (fruits, grains, etc)? Sounds like white sugar / turbo wash is the best bet... then you age/flavor as needed after distillation.

The makeup of the wash, grain/fruit etc, is responsible for the flavour, the color and oakiness comes from aging in oak.
If you have not done it yet, try making UJSSM or rum and you will get the flavour come through in your distillation, oak then adds to that flavor to produce the finished product.

[digitalhippie]

Well, here's what I've done so far....

I ran a turbo/sugar wash in reflux mode..... came out pretty well (for neutral spirits).

I have a brown sugar / molasses wash that I was planning on running (as I said in my orig post in this thread) but it hasn't finished fermenting yet.... so I'm giving it a couple more days.

Instead... I had 5gals of pomegranate mead that was 4wks in, ferment was pretty much done and I had to re-rack it. So I racked 2gals off into sep jugs to clear up as mead... then I ran the rest thru the still. The result was pretty clear, slight yellow/orange tint to it, but almost no flavor. After I made the cut to tails, it got a little more orange... but the flavor still seemed pretty weak.

The brown sugar / molasses wash should be done in the next day or two... so that's the next run...

[Maynard]

Well this is how I run my Bok, the full column separates into 2 pieces. The top part has about a foot of column before it hits the plates and then condenser. This is what I run in "pot still mode". I run it real slow once it heats up. The temp usually settles around 82*C at the take off point and gradually rises after a couple hours. The valve is open all the way during the entire time. Make proper cuts, I learned the bad flavors through neutrals. I have my first rum ageing now and there is pleanty of flavor.

[digitalhippie]

I see what you're saying... I'd be better off if I made it more modular so I could run just the head on top of the boiler w/o much column.

[rad14701]

I see what you're saying... I'd be better off if I made it more modular so I could run just the head on top of the boiler w/o much column.

Yes, that makes the design much more versatile with only a few dollars of extra expense... Some folks go that route and others don't based on personal preference...

[digitalhippie]

I just got back from the hardware store... picked up a few parts so I can make it modular.

[digitalhippie]

Done and done. With a few threaded 2" couplers I made the head removable from the column. Now I can run the head directly on top of the boiler... about 4-5" from the top of the pot to the bottom plate... can't get it much shorter.

Also added a small 7" lebig to the output tube... because I, like other bok users, have noticed the output in potstill mode is VERY hot (comes out steaming).

Hopefully give it another run tonight with the molasses / brown sugar wash and see how it goes...

[digitalhippie]

Ran half the brown sugar / molasses wash last night with the shortened column. Got better results... still think there's room for improvement. So I insulated the lower part of the column again (only about 5", everything below the output tube) and I wrapped some insulation around the boiler pot itself... also replaced the needle valve with a 1/4" union so there's no restriction there anymore. Going to run the rest of the brown sugar / molasses wash tonight and see how it goes.

[rad14701]

I'm planning on removing my needle vale for my next pot still mode run as well... Even with the needle valve wide open I get too much reflux...

[digitalhippie]

Been too busy the last cpl days to post up results. I ran the shortened column with no needle valve and the insulation around the lower column and boiler.... results were definitely better. Got more flavor coming thru to the spirits now. Probably about the limit for what I can do with this design.... since I can't shorten the column any further. I think the only other place for improvement would be some good insulation for the lid of the boiler. If I can find some spare foam housing insulation I'll cut out a circle and give it a shot.

Thanks for all the advice!