Distillation - Part 2

I shared the distillation column photo from Maker's Mark yesterday. The photos today were taken at a 2013 tour of Bayou Rum just east of Lake Charles. The tour guide was very knowledgeable of the process and our tour group was small enough for me to ask a few questions. After the tour knowing I was a chemical engineer, he took my family group up on the column platform for a closer view and allowed me to take a few photos. All I had was an iPhone 4 at the time so this is the best I can offer! A more technical discussion is included with the photos if you are interested - otherwise, enjoy the pretty photos and construction of the column.

The two distilleries are different in that Maker's Mark is producing bourbon using a mix of wheat, rye, and malted barley. Bayou Rum is obviously making rum and uses sugar cane to provide the sugar for fermentation.

This is the upper portion of the column - where the real work/distillation/purification is taking place. Just below each sight glass is a distillation tray where vapor from below is stripped of water with ethanol vapor continuing up the column. The ethanol in the liquid from the tray above is vaporized to eventually be captured in the overhead product. Each tray going up the column obtains a higher and higher purity of ethanol. The vapor coming from the top is condensed to a liquid in the heat exchanger to the right of the column. A portion of that liquid is what is sent back to the column as reflux above the top tray (see the piping going back just above the top sight glass). The other portion of the condensed liquid is the product.

The photo below is the base of the column. They inventory the column with the mash - much like the old moonshiners. The mash includes the sugar cane bagasse. You see they have a mixer (motor to the left) to keep the water/ethanol mixture from settling with the bagasse. As heat is applied to this base, the water/ethanol mixture boils to produce vapor going up to the first tray. The first compounds to boil are lighter than ethanol and includes methanol (make you go blind if you drink it). The distiller uses the top temperature to know when the unwanted compounds like methanol have been boiled off and they can begin collecting the condensed liquid as rum. As more and more of the ethanol is boiled out of the batch in the base, heavier compounds will begin to vaporize. The distiller does not want those heavier compounds in the final product. So the art of this process is knowing when to begin and stop collecting the distillate as final product. They then have to empty the base of the remaining contents and start the process all over again.

Though I do not have a clear photo of the nameplate of the Bayou Rum column, it appears to have the same signature as the Maker's Mark column. There probably are not a lot of manufacturers of copper/brass columns!

The Maker's Mark column did not have this large base. It is not clear if that column is run as batch or as continuous (a whole other subject not for today) but my guess is continuous given what I see and know about the amount of liquor produced there. If I could see the top of their column, we would know for sure as the ethanol product would be taken off before the very top (side draw) of the column. It certainly appears they have already separated the fermented liquid from the grains before they go to the column.

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