Heads, Hearts & Tails

[Bobje]

My understanding of the whiskey distilling process is that in a pot still, the emerging distillate at the beginning and end of the process contains unattractive congeners, so this needs to be discarded or redistilled. Part of the skill of the distiller is deciding when to make these cuts, preserving the best heart.

 

I don't think I understand this in a column still, as the process is continuous, and there isn't a time in which cuts would be made. How do the congeners fall out in a column still, and don't make their way into the desirable distillate?

[tanstaafl2]

4 hours ago, Bobje said:

My understanding of the whiskey distilling process is that in a pot still, the emerging distillate at the beginning and end of the process contains unattractive congeners, so this needs to be discarded or redistilled. Part of the skill of the distiller is deciding when to make these cuts, preserving the best heart.

 

I don't think I understand this in a column still, as the process is continuous, and there isn't a time in which cuts would be made. How do the congeners fall out in a column still, and don't make their way into the desirable distillate?

 

Column stills are capable of being continuous, and certainly can run more distillers beer than a pot, but they really aren't run in a continuous way.

 

Maybe this will help. Most things have been discussed here. Just a matter of finding it!

[Don Birnam]

23 hours ago, Bobje said:

I don't think I understand this in a column still, as the process is continuous, and there isn't a time in which cuts would be made. How do the congeners fall out in a column still, and don't make their way into the desirable distillate?

 

See below.

 

18 hours ago, tanstaafl2 said:

 

Column stills are capable of being continuous, and certainly can run more distillers beer than a pot, but they really aren't run in a continuous way.

 

They are continuous, as opposed to batch.

Continuous as fresh mash is always being pumped through it, a pot still is filled, distilled, emptied, cleaned. Repeat, repeat, etc.

Also continuous as the distillate (alcohol) can be drawn off at the desired 'proof' and 'purity' (purity in this context means water and flavoring components) throughout the run.

Yes they occasionally are shut down for cleaning, but when running they are continuously producing the same quality booze.

In a pot still the proof is constantly changing and the purity is also different as it 'cooks', so pot still distillate is also batched so it contains all the flavors from the run as opposed to if you were to draw off and barrel at different times in the run.

 

As far as operation is concerned.

There are two columns, fresh mash is pumped through a pipe that runs through and winds around the inside of the rectifying (second) column top to bottom, where it preheats the mash as well as performs as a condenser. From there it goes up to the top of the analyzing (first) column, from there it pours out onto perforated plates that act as mini stills. Near bottom of the analyzing column steam is admitted and it rises up the column heating the plates as well as the falling mash. The heat drives off (evaporates) the alcohols, all of them, good and bad, as well as other compounds that evaporate at the temperature within the column. At the very bottom of this column is a drain for the spent mash.

At the very top of the first column (analyzing) is an insulated pipe that leads to the near bottom of the rectifying column, this carries the alcohol(s) vapor which in turn rises up the column. Throughout this column there are also perforated plates, but these plates (spirit plates) also hold some of the condensed liquid that had condensed and dripped off the mash inlet pipe, where, the different fractions can be drawn off due to increased condensation and the fact that at this level the vapor is the temperature needed to hold all the ethanol, some higher temperature congeners and the desired amount of water (a higher temperature volatile). The volatiles that condense at cooler temperatures, i.e. methanol, continue rising to the very top of this column where it too is condensed and return to the mash tank. The very bottom of the second column (rectifying) is a drain that leads to a pump to force the liquid into the near top of the first column where the 'tails' as it were rain down that column along with the fresh mash and 'heads'. Continuously processing until the plates need to be cleaned. This is done though hand holes along the columns at each plate level. There are also windows, (port holes) at these levels for inspection.

 

[Bobje]

Tanstaafl,

Reading Chuck Cowdery answering similar questions in the 2007 discussion of column stills was very helpful. Thank you.