We don’t condone the use of Continuous Stripping stills as a method of running 24/7 as this is a commercial setup only .
Home distillers should never leave any still run unattended and Continuous strippers should not be operated for longer periods than a Batch stripping session would typically be run to minimise operator fatigue..
With a quick glance at the drawing I can see that you could not making anything for drinking with this setup. Your constantly introducing new wash to be boiled off, new wash with methanol, ethanol as well as higher alcohols and what not all. You wouldn't have the ability to make any cuts at all. For stripping maybe.
... I say God bless you, I don't say bless you ... I am not the Lord, I can't do that ... Dane Cook
Rum and vodka are commercially produced in continuous stills. That was my understanding from my own reading and a tour of the baccardi distillery.
I agree that there is no way to separate out heads but they don't seem to care. Perhaps they control methanol by not producing much of it with their wash formulation.
I was wondering how a continous still controls the quality. Grain whisky is also produced using a continous still. Other than not worrying about it or redistilling the product, it ought to be possible to tune the condensation temperature to allow methanol to escape whilst retaining the rest.
All the continuous stills I know of are the big commercial ones with 40-60 internal plates. The "heads draw" is at the top, and the "product draw" is lower down. Fusel oils still lower. You think equilibrium is important in a valved reflux setup? Multiply that be a couple of thousand, and that's how important it is in a continuous system. I really don't think its feasible in a home system.
Yes, it is a type of fractionating column. The plates have some means of allowing distillate to rise (sieve, bubble-cap, wain&wier, etc.) through the condensate at that level, effectively "redistilling" at each plate. Live steam is fed near the bottom, and the wash is fed about a third of the way up. The fusel oils come off about halfway up, product a little below the top, and the heads (ever wonder why they're called that?) come out the top. Most producers, even most Bourbon makers, use this arrangement. Pot stills are much less cost effective.
For the home distiller, I think everyone would agree that a column with plates would be a gigantic PITA. But you can see some cool pictures in the gallery section at Vendome's website:
Years ago at a distillers convention, they were giving away copper paperweight which were the circles they had cut out to make the bubble trays. Pretty cool, think I've still got it around somewhere.
Lest talk about that continuous striper. I've been thinking about do one myself. It would consist of a single ¾” pipe that would coil in side a sealed water bath. There would be an input pipe at the top and outlet at the bottom. Once the water bath is up to temp the wash would trickle in to the coil and the alcohol would vaporize and go up in to the condenser while the backset would flow out the bottom. The advantage is that it wouldn’t matter how big the container of wash is. So you can make enormous batches and not spend a lot of time setting up and braking down a traditional still. Now of course there are no cuts that can be made but that’s ok. The idea is to reduce the volume from 30-40 gallons to 10-15 gallons that can be put into a keg and distilled in a more traditional way. The trick is to control the flow rate into the coil. So I’d have to come up with a flow valve that would adjust to the changing pressure coming from the wash container. There is more pressure when the wash is full compared to when it is empty. I included a crude picture of what I was thinking. What are you thoughts on that?
This is interesting. Stoker and jmc91199, your construction might work. The spiral could be working as a crude stripping column, and the large area it has compared to a column, can help it work jacketed with bolinig water. You might want to add a liqiud lock in the lower end of the column to prevent vapour exiting this way instead of through the condenser.
And youre right, controlling the feed is one of the most difficult parts in building a continuous still. I have only succeded with two types of feed:
1) A peristaltic pump
2) By feeding the wash through a tube in the middle of the stripping column, and having that tube go through the interior of the column up to the top. This causes the wash to boil where the tube enters the column and the vapour bubbles will push the wash up through the tube. If the feed is too fast, the column will cool down, the boiling will end and the feed will stop, thus regulating the feed to a level the column can handle.
And I agree to the opinion that a continuous still is too comlicated to run as anything but a stripper in a home environment.
Stoker, did you try to build that construction of yours?
I found a drawing of one ow my strippers:
The wash has to be fed to the leftmost vessel to keep an exact level, some 10-30 mm below the opening of the internal pipe inside the column.
There was a guy here the modified one of those old fractionating column water distillers. I wrote to him and he said when he finished it stripped a 5 gal of wash in about 2 hrs depending on abv. He said it was a New World brand distiller. Anyone know what happened with him? I lost his email and can't find the posts or pictures.