What is distillation?
Distill- Dis*till”, v. t.
1. To let fall or send down in drops.
2. To obtain by distillation; to extract by distillation, as spirits, essential oil, etc.; to rectify; as, to distill brandy from wine; to distill alcoholic spirits from grain; to distill essential oils from flowers, etc.; to distill fresh water from sea water.
3. To subject to distillation; as, to distill molasses in making rum; to distill barley, rye, corn, etc.
The Distillation Process
In the most basic sense, distillation is a process used to separate a composite mixture into base elements. It involves a change of state, usually from liquid to gas, and then subsequent condensation to return the now separated elements to liquid state.
The basic distillation apparatus (still) has three parts:
(1) A flask with an outlet tube,
(2) A condenser, and
(3) A vessel.
Distillation has been and is used to separate alcohol from various fruits, grains, wines and beers. Once the raw material (fruits, grains, etc) has fermented it is heated. Since different base elements in the material, such as water, alcohol, and fusel oils have varying boiling points, the elements separate. The distilled material is then collected in a vessel – with care that the heads and tails (undesirable elements) are excluded from the drinkable alcohol.
Types of Stills Used in the Spirit Industry
Alembic Pot still – The oldest and most recognized still design. The flask or kettle is typically copper and resembles a huge onion shape, which liberates the alcohol from the mixture. The vapors rise and pass through a narrow pipe and then through a serpentine coil, a cold-water bath condenses the vapors in the coils, converting them back to liquid form.
Reflux or Column still – A ‘technological’ advance over the pot still. It is more efficient, requiring only a single distillation done in one continuous operation. This type of still allows for exact separation techniques. Also, changing the reflux rate provides great flexibility to create the style and quality of the type of spirit produced.
Origins and History of Process
Distillation, the process of separating a liquid into different parts by evaporation and condensation, is an age-old process that may have began as early as 2000 BC. Some say that the first use of distillation occurred in China, Egypt, or Mesopotamia for medicinal purposes as well as to create balms, essences, and perfumes. Over time, the secrets of the distillation process traversed thousands of miles, moving over Europe, crossing England, Scotland and Ireland, and settling in the Americas.
Water consumption per batch: For every 600 liters of batch, estimate about 1200 liters of water needed. The water is required for cooling and should not exceed an inlet temperature of less than 20 °C. The water outlet temperature is ~ 70 °C. If the costs for water are high, there are technical solutions to circulate chilled water. The temperature of the output distillate should be about 20°C.
Steam consumption: about 100 kg/hr is the standard value for a capacity of 600 liter, assuming 1-hour time to bring the mash to boil. To finish the process, you need about an additional 1.5 hours consuming approximately 70 kg steam per hour.
For the calculation of the energy consumption the following basic numbers are valid: Net 170,000 BTU is required per hour. For gas fired steam boilers this means a 220,000 BTU on input. Based on the BTU value of your natural gas or propane, you can calculate to cost of fuel.