Boka Evolution

Vapor, Liquid or Cooling Management. Flutes, plates, etc.

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fatjohn
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Boka Evolution

Post by fatjohn »

Hi, I wanted to share some success I've had so that others might benefit. I could go thru all the trials, errors, and theoretical thoughts but that could bore so I'll keep it short as I can.

1) I had a pretty typical 2" Boka head about 3 feet tall. I soldered a 10' wrap of copper tubing on the outside of the upper head to help with the cooling. Its attached to the internal condenser flow and I find I don't have to run the cold water that fast to keep it cool; mainly because I don't drive the boiler that hard. I keep the flow just cool to the touch, not cold.
2) I have another typical Boka head condenser mounted in-column a few inches -below- the thermometer and takeoff. There is also another 10' of copper soldered around the outside of the boka head in this area below the take-off. The lower external tubing and lower condenser are connected in-line with some plastic tubing. *Hot* water is recirculated thru the lower condenser. I'm pushing the water with a little $20 high temp pump and my water reservoir is a little Igloo cooler. The biggest problem I've had with the experiment is when the recirculating water gets hot (ie.175 degrees), the plastic tubing wants to slide off all the fittings; this seem fixable with some sturdier tubing. I also shove a couple of copper scubbers in the lowest area of the head pipe for good luck.

I always run the takeoff wide open and I have all the little cracks taped with teflon or smeared with flour. No vapors should be escaping.

My theory behind this setup is that the hot lower condenser is removing water from the vapor but is hot enough to let more volatile vapors pass to the upper condenser for collection. I let the rig warm up fairly slowly like is always suggested. The lower condenser can be primed with some hot water to help the process along. Keep an eye on the thermometer... once its starts moving above room temp it goes pretty quick. Early foreshots might start coming in the 150 degree range.

Once the foreshots are off you're good to run slowly up the temp spectrum from like 178 to 198. Stop the hearts collection around 60% or when it starts to get bitter. If you try to run too slowly the takeoff will spit bubbles and the product will taste overworked. If you go to fast, then it will smear and get a bitter aftertaste. Try to stabilize the initial temp in the mid 170's, let the parrot run a thin matchstick; then when production slows, give her just a touch more heat and let it run till it slows again; then a little more heat and repeat. As you add heat, check the upper condenser is still cool. Keep drafts away from your flame; the flame is pretty low and anything affecting the flame will make it harder to hold the temp steady. The hot lower condenser system keeps the rig quite stable from a quality perspective.

For the mash I'm using apple cider. I ferment 13 gals and keep 1 gal on the side. To the cider add 6 lbs sugar, pectic, yeast nutrient, and prepped S-04 yeast. I put the buckets of ferment in an insulated box in a cool basement for a long week and it seems to stay in a happy temp range on its own. After ferment it tastes pretty flat because the sugars are gone so I put the reserved gallon of cider back in (along with any tails); the un-fermented cider brings a hint of sweet ester to the end product.

I think this design will scale and should eliminate the problem of hot channels in the lower head pipe.
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bearriver
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Re: Boka Evolution

Post by bearriver »

To properly describe the first bit, you added a dephlegamater below the slant plates making it a CM/LM combo.

The tubing wrapped around the outside of the column is creating some passive reflux, but certainly very inefficiently. If there is packing on the other side of the pipe wall, it is messing up you column's equilibrium at the top. Not a good thing...

You are addressing a fictional issue here. Channeling isn't a real concern in a generic boka. Several members such as Odin and Skow with glass columns have shown this to be the case. Go watch a YouTube vid of it yourself, and you will see the refluxing alcohol being sucked into the center of the packing like a wick.

May I ask where you got this design from? All I'm seeing is a simple boka devolving into a poorer design at additional costs... Adding the CM coil just makes it even more cornfusioning....
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bearriver
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Re: Boka Evolution

Post by bearriver »

Ive read it 3 times, but maybe there is something I am missing here with your description....

Will you please post a picture of this still?
fatjohn
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Re: Boka Evolution

Post by fatjohn »

The head is on the shelf right now but I could set it up and take a pic soon.

You said, The tubing wrapped around the outside of the column is creating some passive reflux, but certainly very inefficiently.
I agree with you but I was really shooting for a more efficient pot still. In looking at the design at http://stilltutorial.com/pics.php" onclick="window.open(this.href);return false;" rel="nofollow , I saw they had an external coil. So I put that on my boka , below the plates, assuming that it would be beneficial. But with cold water running through the coil, I had to jack up the heat and got higher proof , nastier tasting output. Then I thought of running hot water through the coil, which was an improvement.

If there is packing on the other side of the pipe wall, it is messing up you column's equilibrium at the top. Not a good thing...
I agree. When I pushed copper scrubbers into the area where the lower coil was operating , it did not help.

Since hot water in the lower coil seemed to be an improvement (minus the scrubbers), I thought of ways to get hot-water-regulated copper tubing in-space with the vapor. Then I realized I was imagining a condenser running hot water. So I made another condenser like the one in the top of the boka and put it in the body below the takeoff (in the same area as the lower external coil). I'm recirculating the water of the lower condenser and external coil because I don't want the water in the dephlegamater(?) to boil but I want it hot.
{This rig is what I ended up with after the above brain farts and experiments} js
bellybuster
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Re: Boka Evolution

Post by bellybuster »

fatjohn wrote: but I was really shooting for a more efficient pot still.

as soon as you add reflux you no longer have a pot still.
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Re: Boka Evolution

Post by bellybuster »

regardless of the temp of the water in your lower coil, as long as its below vapour temp, you are refluxing. The same can be had by simply adjusting the flow thru the coil instead of the temp of the water in the coil. Simplicity.
Refluxing with no scrubbers only increases the length of your run, not the quality of your product. There will be minuscule amounts of redistillation but for sure not much
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firewater69
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Re: Boka Evolution

Post by firewater69 »

If your wanting to simulate a double pot run, a short cm is a good way to do it imho, because it isn't usually as efficient as an lm or vm especially with a short column ( mine is 16") you can pull of a single run in the 160pr range. i have an lm as well but i use my cm for whiskey.
Moonshine.... American as apple pie & it's part of our heritage, history & culture.
fatjohn
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Re: Boka Evolution

Post by fatjohn »

I can imagine in a big copper dome, pot still, that vapors rise, contact the wall and condense. You can say this is not reflux, that's ok. I was just trying to capture that effect in my boka. I have no reason to debate, I'm just reporting that the flavor of this latest setup is better than what my boka was putting out with just copper scrubbers in the column. The flavor is also better than my 2" column to lynearm. cheers, fj
bellybuster
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Re: Boka Evolution

Post by bellybuster »

Passive reflux on the big stills is indeed reflux but not induced. Hence "passive". This effect is minimal to nonexistent in our little hobby stills.

No ones debating your results, just pointing out that there may be an easier way that one or two fellas here may have tried before.
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Re: Boka Evolution

Post by Hound Dog »

fatjohn wrote:
My theory behind this setup is that the hot lower condenser is removing water from the vapor but is hot enough to let more volatile vapors pass to the upper condenser for collection.
FJ, I could be wrong but just as the wash in your boiler is a mixture that heats up together, not separately, the vapor is the same. It will all condense at one temperature, not separately.

Many come on board thinking they can heat a wash to 172 and just evaporate the alcohol out of it. This is not how it works. Your method with the vapors seems to be wanting to do the same thing in reverse. It will not do this either.

There are many more scientifically savvy members on this forum that could explain this better or even correct me if I am wrong but this is my take on the idea.
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myles
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Re: Boka Evolution

Post by myles »

bellybuster wrote:
fatjohn wrote: but I was really shooting for a more efficient pot still.

as soon as you add reflux you no longer have a pot still.
Sorry but this just isn't acurate. There are many traditional pot stills that do in fact use water cooled devices to add in an extra amount of reflux.

None of this is new and folks have been modifying their pot stills as long as there has been distilling. What do you think a wet cloth placed on the cap of a pot still is doing?

There is nothing wrong with "tweaking" a pot still. How you run it determines if it is in reflux or pot mode of operation.
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bearriver
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Re: Boka Evolution

Post by bearriver »

SoMo is happy with his pot still mods. Find a post from him, he should have a detailed thread in his signature.
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