Fractional distillation

The slower one distills the mash, the purer the alcohol will be. To obtain as pure spirit as possible one should use a still with a distillation column. A column is a vertical tube that extends 590 mm or more from the boiling vessel. The column is usually filled with an unsymmetrical filling with as large a surface area as possible. The vapour passes up through the column until it is cool down to a liquid alcohol. Boiling takes place all the way up the column. Because of the differing boiling points of water and alcohol a separation of these occurs in the column and which is termed fractionization. The temperature at the base of the column becomes the same as that of the boiling vessel (towards that of water, 100°C) and the temperature at the top is regulated by the heat source to 78°C. Passing from the bottom to the top the temperature drops off all the way up. So the mash (water) with a higher boiling point condenses and runs back down into the boiling vessel, whereas the alcohol gets through without condensing. One can further improve the column by fitting 2-3 thin tubes through it, through which cold water is passes through. The tubes cool down the column filling, and by this through-cooling, water and fusel oil are separated extremely effectively by faster condensation on the cooled filling. By regulating the speed of the cooling water one can

95%

78,15°C

94%

93%

91%

79 °C

89%

79,2°C

80%

79,9°C

47%

83,1 °C

7%

94,5°C

ash 0,6% \ 99,5°C \

regulate the temperature in the top of the column. With more powerful cooling (increased water flow) the temperature cools and lowering the cooling effect raises the temperature. This means that one is independent of a stepless heater for the still. One sets the heat source roughly, and adjusts with precision using the amount of cooling water running through the column. The taller the column the more effective is the fractionalisation. But for home distilling only a 590 mm (2 foot) long column is needed. A longer column only fractionally improves the results, but one needs considerably more heat for the vapour to make it through the column. One distillation with a distillation apparatus provided with a column corresponds to eight ordinary distillations. After the column is located a condensation cooler where the alcohol is condensed to liquid form.

Distillation gives best results with the distillation temperature set 1 to 2 tenths of a degree under boiling point. The boiling point of alcohol is 78.319°C is the temperature that produces the best distillate. 95% alcohol has a boiling point of 78.15°C. If one uses a boiling plate connected directly to a power source for the distillation apparatus, one can, with advantage, use a stepless power regulator (triac) between the socket and the boiling plate. This gives a "volume control" of the heat, and the boiling plate can be set on maximum. During the initial heating up stage, the regulator should not be used. It should be connected when the column has become hot about 150 mm above the still. If one only has recourse to limited cooling water and a low heat the apparatus will be affected quite easily by such factors as draughts (drafts), when opening doors, etc. If this should occor, increase the heat and water supply slightlye so that the distillation becomes more stable at the same head temperature. Distillation apparatus should be located in a draught-free place. The first drops of distillate to emerge (fore shots) are primarily comprised of acetaldehyde. Acetal is also present, a product very similar to acetaldehyde. So-called aromatics are also present. They are not toxic but taste will be considerably improved if they are discarded.

When we have finished the distillation process, the apparatus should be allowed to cool and the mash should be emptied down the lavatory (toilet). Hot mash has an foul smell. If the apparatus is allowed to stand and cool one must never block the outlet for the distillate. It is easy to get a kink in the tube from which the distillate emerges. If this outlet is blocked, during cooling a vacuum is formed in the boiling vessel. This is because the warm air and mash shrink as they cool and takes up considerably less volume. If the boiling vessel is of glass this underpressure will cause it to implode. If it is of stainless steel it will be screwed up like a steel rag. To avoid this the thermometer and the connection between the column and boiling vessel should ALWAYS be undone after distillation process to allow air to enter and equalise within the still and the column.

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