Bok plans - Yer input needed

[knucklhed]

So I've settled on building a bok and have the plans laid out but still have a few unanswered questions and a few things I'd like to get confirmation on before I start hacking up copper...

Primary use (I hope!) will probably end up being rum/whiskey/brandy, but the wife is gonna be looking for some wodka production outta me... So I'm looking to get a 2fer outta this still.

What I'm working with -

-2.5" copper for the column - got it used for scrap price
-Planning on a 100cm scrubber packed column that can be reduced down to 50cm for potstill use - It seems like 100cm is kinda on the small side for 2.5" dia from what I've read, but I'm kinda limited to ceiling height in the garage so...
-tri-clamp & adapter ordered to attach it to the 15.5 gal keg
-Condenser plan is to use a 13mm cold finger with at least 1 wrap of 1/4" around it - looks like 20-25cm is pretty common - see question below.
-on a well, so cooling water consumption isn't a concern.
-1/4" take off with brass needle valve
-Propane for heat

The questions I have:
1) is the 50cm column too much/not enough for pot still use? What else should I consider?
2) with regards to the condenser, I'm wondering if a single wrap is enough to knock down the volume of vapor that a 2.5" column is going to produce, I have the space inside the pipe dia, should I just do a double wrap?
3) The brass needle valve I got has a rubber seal above the t-handle valve threads, as long as I mount it "T" side up, do I need to be concerned about the seal coming in contact with distillate? I also realize that I'll need to pickle the valve before use.
4) Is 1/4" take off going to be large enough when running in pot still mode?
5) the 2" tri-clamp adapter will be threaded into a female copper NPT-to-solder connector, I'll use PTFE tape on the threads, but do I HAVE to solder that joint where the column connects to the female copper? Would a flour paste work for sealing that joint? The reason - Since I plan on using the still as a reflux and pot, it would be nice if I didn't have to buy 2 of the threaded female copper connectors, I could just slip the fitting off and use it on either the long or short column. Over thinking it?
6) Obviously I need to leave some head space in the boiler, how many liters are guys usually running at a time? Seems to me that I saw 38-40L somewhere, I plan on running wash batches of 120L, if I could run 40L at a time, that would give me 3 runs per batch of wash.
7) Not a build question, but - first few batches are going to be Hook Rum (after clean out runs of course) and the recipe calls for baker's yeast - any recommendations of brand? Fleischmann's? Redstar? any others I should consider? I have a commercial distillery nearby that produces a pretty decent rum and the fella there is willing to sell me enough of the yeast they use... I believe it is Lalvin V1116, says his wash ends up at about 14% - that seems like a good yield (better than baker's (8-10%?) right?) without being too high (produces off flavor from more fusels right?) like a turbo...


That's about all I can think of for the moment, Thanks for the help!

[Usge]

The questions I have:
1) is the 50cm column too much/not enough for pot still use? What else should I consider?

In general, the shorter it is..the more flavor you are going to bring over. That's the consideration/trade-off. Taste it taste. Some people like a little lighter, some people like all the flavor they can get.

2) with regards to the condenser, I'm wondering if a single wrap is enough to knock down the volume of vapor that a 2.5" column is going to produce, I have the space inside the pipe dia, should I just do a double wrap?

It might be. Hard to say...just depends on how well it fits inside the column and how much water flow you got. But, in general, I'd recommend either using a cold finger with that single wrap or doing a double wrap.

3) The brass needle valve I got has a rubber seal above the t-handle valve threads, as long as I mount it "T" side up, do I need to be concerned about the seal coming in contact with distillate? I also realize that I'll need to pickle the valve before use.

Good question. I don't really know how much exposure there is for this seal (it varies depending upon manf/construction). I do know stainless with PFTE seals cost a good bit more than standard brass ones.

4) Is 1/4" take off going to be large enough when running in pot still mode?

Another good question. It depends on how much heat you throwing down. Frankly, if it were me...this is just one "more" reason to build an entirely separate head/liebig just for running potstill mode. It's never going to be the same thing. That said, I use my shorter column boka wide open in potstill mode and it works ok (packing and all). But, it's not the same as dedicated potstill head. You may prefer one way or the other. Up to you.

5) the 2" tri-clamp adapter will be threaded into a female copper NPT-to-solder connector, I'll use PTFE tape on the threads, but do I HAVE to solder that joint where the column connects to the female copper? Would a flour paste work for sealing that joint? The reason - Since I plan on using the still as a reflux and pot, it would be nice if I didn't have to buy 2 of the threaded female copper connectors, I could just slip the fitting off and use it on either the long or short column. Over thinking it?

All I can do is give you some advice based on experience. If things are refluxing down that column, it will find a way out if it's not really sealed up good. In general, if you have a pretty good overlap on your join....you might be able to get away with paste. The problem is..when things "wiggle" it breaks the seal sometimes. I had a shorter bubble cap that I used paste between sections on..and it worked fine in lower sections, but up by the dephleg...leaked like a sieve. It would soak the paste seal till it got wet, then start seeping through.

6) Obviously I need to leave some head space in the boiler, how many liters are guys usually running at a time? Seems to me that I saw 38-40L somewhere, I plan on running wash batches of 120L, if I could run 40L at a time, that would give me 3 runs per batch of wash.

I'm not running that big. I have an 8 gallon pot, I usually run between 5-6 gallons in it.

7) Not a build question, but - first few batches are going to be Hook Rum (after clean out runs of course) and the recipe calls for baker's yeast - any recommendations of brand? Fleischmann's? Redstar? any others I should consider? I have a commercial distillery nearby that produces a pretty decent rum and the fella there is willing to sell me enough of the yeast they use... I believe it is Lalvin V1116, says his wash ends up at about 14% - that seems like a good yield (better than baker's (8-10%?) right?) without being too high (produces off flavor from more fusels right?) like a turbo...

I've tried both Fleischmanns and redstar and didn't find anything worth mentioning different between then two. V1116 is wine yeast I think. Does have higher tollerance, but also tends to produce fruity/wine notes.


That's about all I can think of for the moment, Thanks for the help![/quote]

[knucklhed]

Thanks for the great replies Usge!

I appreciate any input I can get, hopefully it will keep me from making any mistakes that I'd regret!

[Usge]

Thanks for the great replies Usge!

I appreciate any input I can get, hopefully it will keep me from making any mistakes that I'd regret!

Ah....I wouldn't worry too much. Ain't much you can't fix.

Boka is already a well thought out and refined design...using last iteration/templates. It will work even as it is (packing and all) run in potstill mode. It just tastes a little different that's all. Who knows...you might even like it better! than running straight off the pot! I run mine off stove top gas so I don't have that much heat/power to put through it. I'm using 1/4" tube and it seems to work fine for the amount of flow I get in potstill mode. But, if you have propane and a really powerful burner, you can of course..push it beyond it's limits. One important thing is just make sure your outlet tube that goes to needle valve slopes "down" all the way. Otherwise, it could back up into the plate.

[knucklhed]

I've got 120l of hook rum wash fermenting right now - coil condenser is done, parrot built, 2" keg flange adapter due to arrive today, hopefully will have the slant plates done before friday so I can run my clean outs... House smells like molasses... a smell I could get used to!

[knucklhed]

Quick question, for the atmospheric vent, is there any need or any harm in using say, a 3" long piece of 1/4" copper tube and soldering it to the cap (to hold it in place) and to the side of the 1/4" condenser coil? It would be unvalved - no restrictions

My thinking is that the copper tube would be cooled enough that if there was any vapor that would escape, it should condense as it passes thru/into this short piece of tube.

I realize that if the condenser is doing what it should be and my heat input is set right, there shouldn't really be any vapor escaping, but since I'm learning and prolly gonna make mistakes, will it hurt anything to have it?

[Braz]

It won't hurt anything but it is totally unnecessary. All you need is a couple of holes (3/8" is good) in your cap. If you are blowing ANYTHING out the top, vapor or liquid, you got a problem. So there is no need to add extra condensing capacity to your vent.

[knucklhed]

Thanks bro!

[myles]

I am going to disagree with braz, I like to put a condenser on the air vent. All it needs is a small liebig connected into the coolant supply for the reflux condenser. Even just passing a small tube through the supply hose.

It is a tiny point, but it is easier to see condensed liquid dripping where there should not be any, compared to trying to see escaping vapour, at the top of the column

[seaguy]

I have a 2" bok and I put a 3" long 3/8 cu tube for the cap vent and I put a clear tube on it going into an old milk bottle. I have pushed it a little too hard before and puked out the top. Now if it happens it goes in the bottle. If its vaporing it drips in the bottle and is easy to see letting you know your pushing it. I use more condenser than you described so at 2 1/2" using propane it won't be too hard to crowd your condenser.