An Interesting Facebook Discussion with Richard Seale of Foursquare Distillery

Richard Seale - Foursquare Distillery

     Here are some excerpts of a Facebook with Richard Seale.  It has a lot of very interesting information and is a great discussion of the working of these three types of stills.  I hope you find this to be as interesting and I have.

Here is a distilling question:

I have made some fermented molasses wine and I have three stills.

(1) the common pot still - French or Scottish
(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)

Which rum that I distill will have the highest amount of congeners?

Mathilde de Ramel Congeners are produced during fermentation...

Richard Seale yes, but after distillation which rum will have the most left

Roger Morenc All 3 can extract the same amount. It's a question of how well compressed/ isolated they are as they come off the still and then what the distiller chooses to keep.

Richard Seale yes they can but in practice will they? does the distiller have the same choice in all 3?

Christian De Tomate Should be easier to isolate congeners with 1 and 2 as it's discontinuous and you're covering a wider range of molecules

Richard Seale yes, and which of 1 or 2 will give the greatest control over selection?

Roger Morenc Is it really greater control or the opposite of control? The congeners just spill over the still top with less discrimination than with plates. I just go back to the idea that if you completely run out all the alcohol of a ferment then you're going to get the same congeners. It's only a question of what you want to keep and what level of precision capability you have to keep/discard.

Brian Rolls Hmm. The Savanna French column has a pretty high congener count, as does the modern Jamaican pot and the amateur Haitian homebrew. So all three types can do it.
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.

Richard Seale Indeed it is the one with the "least ability to control" that has the highest congeners, but you have chosen the wrong one - hint - it is the column still with the least control

You can find this discussion in its totality on Richard Seale's Facebook page.  Here is Richard"s summary of the discussion.

Richard Seale So answer time (well it is mostly above):

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.

Sean Nielsen Richard Seale Well put. Just like how American whiskey producers tout their proprietary yeast strains as a key component in their product, whereas most of the world outside of the US talks little about their yeast.

Richard Seale Precisely.

I hope that you take the time to go to Richard Seale's Facebook  Page and read the entire discussion, it is worth the time.