When I first started looking at Stills and Distillation over the Internet I saw a lot of different styles. Upon further reading you discover there is really only 3 kinds of stills, The Pot still, the Reflux still and the continuous still (which sounds nice, but it is not really practical for the home distiller). The oldest is the Pot still, probably made of clay and a hallowed out branch. Pot stills have been made bigger than homes and as small as a teakettle. The small ones with less capacity heat up faster and your run time is shorter than when using a large still. They produce less volume, but when design’s taken into account for size and the shape of the still. It can produce with the same results as a larger still. So the question is “Do I need a large or a small still?” The answer is another question. “How much time do you have to devote to a distillation run?” If you have 4-5 hours = larger still, 2-3 hours = smaller still. These numbers change when doing essential oils. Pot stills large or small are the easiest to use. They just require you to heat it slowly and keep up on the heat of the worm water. The worm water is what the steam inside the coil pipe is traveling thru to condense and return to its liquid form.
Pots stills are usually made of copper. One reason is that copper is easy to form into different shapes. And another is when the hot steam is in contact with the hot copper pipe the copper takes out the sulfur in the distillate. This makes water taste better and makes liquids smoother. A pot still made for drinking water should have a copper column; a still that has a stainless steel pipe leaves the “tinny-ness” in the liquid. But if you do not mind a little sulfur in your drinking water the Pot still’s top can really be made of any material, from clay to stainless steel. I would not use steel for just drinking water. Fuel stills can and do use steel very well. Even a primitive still cleans water. If you can bring water to boil in a pot, you can use it as the base for your pot still, again I would not use steel except for Car ONLY fuel. What I am saying here is that in the future if the laws change to allow home distillation of alcohol. You do not EVER what to drink any alcohol that has not been distilled in steel or aluminum. Alcohol will pull out the impurities out of those materials and contaminate the distillate.
There are many examples of where people took and hung baskets filled with botanical from the “lid” inside of the still. They filled these baskets with plant material and the hot steam from the liquid below caused the plant to release its oils. The oil and water travel together up the pipe to be condensed and returned to the distiller oils and water that they later separate again to make essential oils. The left over water is a hydrosol (water/oil mix) and is used as a Perfume. The Distillation run time will be depending on how plant material you have. But it is as simple as 70% of your oils will come off in the first 1/3 of your run. Ok, you have 3 gallons of water, boil 1 gallon per hour, your run will last about an hour. When you do to long on a run your oil will become more and more liquidity or it becomes a Hydrosol and is very hard to separate. I will be covering how to make your own oil separator out of copper later. I hope that this helps your understanding of the Pot still. Questions?