45634Re: Internal Reflux in a Pot Still - Need Help
- Aug 1, 2009--- In Distillers@yahoogroups.com, "jamesonbeam1" <jamesonbeam1@...> wrote:
>Hey Jim, I'll throw my 2 pennies in the ring here.
> Hi All,
> This situation has been causing me a bit of grief for some time now.
> I've built several pot stills - some with flat covers, but my first
> still used an aluminum Bundt cake pan that looks like this:
> I cut down the center a bit and fitted a 1/2" copper riser to my copper
> lyne arm. I started using this with an aluminum boiler then switched
> over to 15 liter SS boiler with a flat lid.
> I recently found that that bundt pan fit fine on the SS boiler and tried
> some runs with it. The still looks like this: [My First still]
> The riser is 24" high and necks down at a 45 degree angle for about 2
> and 1/2 feet to the condenser - a copper, double barrel shotgun style,
> in a 24 quart plastic beer cooler (I know sounds kinky lol), but works
> the nuts.
> Anyways when using this bundt pan with a 14% sugar wash, i am
> consistantly getting around a 75% ABV (150 proof) on the heads. Now
> according to Tony's Pot Still Purity chart I should be getting around a
> 58% ABV on the Heads like this:
> Input your Pot still characteristics
> Initial Volume of Wash L
> Alcohol Content % by volume
> Initial Temperature C
> Power during Heat-up W
> Power during Distillation W
> %Internal Reflux %
> Time Temp Collected Purity Total Collected Total Purity
> Now when using a flat head, It get closer to these figures. I
> understand about inernal reflux in a pot still, but does just the fact
> im using a domed head account for such a drastic increase in ABV (17% or
> I know Whisk(e)y makers, and many professional stills use domed heads,
> but when I key in the different internal reflux percents in Tony's
> calculator, it still shows a 58% ABV comming out.
> Is it me or is it Tony Ackland's programming???
> Thanks for any help.
> Vino es Veritas,
> Jim aka Waldo.
Reflux Rigs are somewhat easy to calculate purity if you know and can do the math. They are also, for the most part, of the same design. Column diameter, length of column, insulated column, packing. Pot still are totally different animals and although some of you guys kid with the "Simple Pot Stiller" and "Purist" titles there is nothing simple when it comes to a pot still. To me those calculations are worthless just because of the sheer number of different Pot Still designs out there. Z Bob runs a Keg with 2 feet of uninsulated 2" pipe on top and says his brandies lack flavor, Other guys try to de tune reflux rigs to run them as pot stills. Your design is especially interesting because you have that "pocket" up top and I bet the creates an enormous amount of reflux. Add to that a 2 foot uninsulated riser and you got yourself an efficient pot still. Consider this change I recently made to my pot rig. I too, like Z Bob am looking for more flavor in my whiskeys. My pot rig is a 32 qt boiler with a mixing bowl on top. It HAD a 6"L x 1"Dia riser tee'd to 3/4" then over 24" and elbowed straight down to the Liebig. The change that I made was cutting off the riser and capping it off. I then cut a hole in the mixing bowl about 3/4 the way up the side and brazed 1" pipe in there and then adapted it to 3/4" to the liebig.. That seemingly simple change dropped the ABV on a strip run 6%. Insulating the bowl should reduce efficiency as well. Insulation is cheap. Get you some of that silver bubble wrap stuff from lowes and insulate that riser to the downturn.
Here is another short example. Using 2"x 24" column under my X flow head, Unpacked and un insulated at 1440watts will put the Heads from a strip run (10-12% wash) at about 85% and the overall run will be in the 60's.
There are just too many variables.
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