|Richard Seale - Foursquare Distillery|
(2) the Caribbean pot still with retorts and some plates
(3) the Caribbean Creole 'single' column continuous still (say 24 plates, 15+9 strip+rect)
I would guess that the still that has the most likely rich congener counts would be the one with the least ability to control the output. So a simple pot still with a short neck for the least separation.
The question is really about the discussion and not the answer. The purpose is to clear up some generally held myths and misunderstandings.
The "correct" answer is (3). The single column will in practice have the most congeners. It is common to believe that anything from a column is "lighter", more "purified". This is not correct. Surely you do need a multi column to make neutral and the coffey double column will make a light spirit. But in this single column, the rectification i.e. the separation of the "undesirable" heads and tails is low and no cuts are taken. This gives a very "heavy" i.e. high congener spirit. Think Caroni. Think Rhum Agricole.
Now if you took no cuts from the pots they too could make a very heavy spirit but in practice the distiller will find it very easy with the time driven output of the batch process to take some nice heads and tails cuts. The spirit will then have lower congeners compared to the single column. Now I have simplified a bit. High contact time with copper and heat will create and remove congeners versus the column but lets keep things simple.
But which of (2) and (3)?
Well in theory they can make the same level of congeners. The congeners are in the wine/beer and it is the cuts, not the plates that drive the nature of the distillate. See my earlier piece of plates. The plates cannot make the congeners vanish into thin air. It is very common again for people to believe once a column/plates is involved, somehow things will be more "pure".
But that is to fundamentally misunderstand the difference between the column in continuous distillation and the column in batch distillation. Again, refer to my earlier piece on plates. In a continuous system, the column separates physically and given enough plates we can isolate and remove heads/tails with draws at physical positions. In the batch system, our plates only affect the timing of the heads/tails and so we can still choose to keep as much as we want.
The Caribbean pot still with the retorts/plates will afford the distiller greater control over the timing of arrival of all congeners. The additional plates/retorts give greater separation by time over the arrival of the congeners. The distiller can then simply be more selective in what he takes and what he rejects. So IN PRACTICE a rum from the Caribbean pot still may have slightly lower congeners i.e. (2) lower than (1) because the distiller has been able to carefully extract more undesirable congeners.
It is the best of all configurations.