Introduction. I wanted to have a versatile still that could be used to make a variety of spirits from vodka to rum. My previous stills - (Version 2 and 3) were simple pot stills that I used to make rum, the latter version producing excellent results. However, I wanted to be able to make vodka for coolers. Not being a vodka drinker, I didn't need to have 95% purity, just needed a still so I didn't have to distill through my pot still three times.
Design Criteria. Living in an apartment space is a premium. The most important design criteria was space - this still has to be easily stored, setup and taken down and stored again. The second design criteria was safety of materials. I wanted a still made of only stainless steel and copper with no questionable materials - such as telfon tape or does the brass fitting have trace amounts of lead, etc. And finally the last design criteria was this still should be durable and last for years to come.
Description of still. The still uses a 12 quart stainless steel stock pot as a boiler and is heated on an electric stove top that has a maximum power setting of 1500 watts. A stainless steel bowl is mounted on top of the pot to provide 'head room' to prevent foam overs or 'puking'. A small 16" copper column (diameter 1 1/2") is attached to the bowl and raises straight up. Inside this column I can put structure copper packing when operating the still in fractionating or reflux mode. A copper tee is connected to the column to allow the vapors to exit and condense in a liebig condenser and mounted at the top of the tee is a small cold finger condenser to create reflux. The top of the column is closed as opposed to regular reflux columns (such as the bokabob) and the 'open to the atmosphere' safety feature of a still is done like a conventional pot still (no restrictions - open at the output).
Theory of Operation. The vapor path is marked by the red arrows. Vapor flows out of the boiler, goes out the tee and condenses (the dotted red arrow) in the liebig condenser. The cooling water flows from the bottom, through the liebig condenser and out the top as marked by the green arrows. With the reflux valve closed (circled in blue) this is the normal operation for pot still mode.
I can run the still in pot still mode with or without structured packing. By adding some packing to the column a bit of natural reflux will occur and this kind of still is known as a fractionating column.
When the reflux column (blue circle) is open then water flows through the cold finger condenser at the top as shown by the blue arrows. Alcohol vapor will condense at the top and drip down to the packing shown as the dotted yellow line. Purity increases (% alcohol content) and flavor reduces. The still is operating in column mode - great for making vodka and light flavored spirits.