Distillation

Distillation

Alcoholic distillation is a process in which a fermented liquid is heated to separate the ethanol from water thereby increasing the alcoholic percentage of the beverage.

History

The art of distilling was known centuries ago to the Chinese and early Egyptians who used it to produce perfumes.

The art was probably known in Europe by the tenth century.

Christian Monks were some of the first to perfect distilling in Europe, and they developed a potable spirit called, ‘aqua vitae’, translated means ‘water of life’.

Distillation of alcohol

—  A liquid that has been fermented to produce alcohol is put into a closed vessel and boiled.

—  The alcohol boils at a slightly lower temperature than water, and is driven away from the vessel in the form of a vapour, which is carried along a closed pipe into a cold-water tank, where it is cooled, and reforms into a liquid.

—  This liquid comprises the spirit formed from the alcohol and some water, gases and oils that are picked up on route from the closed vessel.

—  These gases and oils are important because as various spirits mature, they give to it their own particular flavour and characteristics, and if this distillation process is repeated several times, pure alcohol is obtained.

—  There are two types of still use in distillation, and the choice of still will effect the final taste and style of the spirit produced.

—  Pot still

—  Patent still

POT STILL

—  A pot still is a type of still used in distilling spirits such as whisky or brandy. Heat is applied directly to the pot containing the wash (for whisky) or wine (for brandy). This is called a batch distillation(as opposed to a continuous distillation).

—  Pot still is older in origin as compared to Patent still. It’s a rounded pot commonly made of Copper.

—  The still has got a tapering funnel at the top (with a bent in the pipe called the swan’s neck) where rising vapours are collected and then carried off to the condenser or the worm.

—  After each distillation cycle the still must be emptied of spent material and cleaned before being reused. Since the process of distillation is not continuous (distillation being done in batches), this kind of still is also called as batch still.

—  The still can be directly heated by open fire or indirectly heated by steam pipes constructed inside the pot.

—  The alcoholic vapours produced by heating and by the successive concentration, are subsequently cooled and brought to the liquid state, giving rise to the distilled product.

Heads, Heart and Tails:

—  The distillate is divided in three parts according to its components and its quality: the head, the heart and the tail
1. The heads: This will be the first products from a distillation and consists of very volatile liquids that we do not want to collect. These include liquids such as methanol and acetone. They condensate at fairly low temperatures and get discarded as they are unsuitable for human consumption.

—  2. The heart: They are  really good .This gets produced at temperatures around 78-84 degree centigrade,  This is mainly ethanol with little flavouring depending on the original wash. As a general guide, the less pure alcohol, the more flavouring will be included. The purer the alcohol, the less flavour it will have.

—  3. The tails: This includes some aromatic flavours. These get produced in the temperature of 84 - 95 degrees centigrade. As the tails include some good flavorings and  unpleasant smell  , it is advisable to take many cuts (collect the product it in a number of small bottles) of the tails to allow flavour blending at a later stage.

                    CONTINUOUS STILL

1-ANALYSER

2-RECTIFIER

3-WASH

4-ALCOHOLIC VAPOUR

5-WASH SPRAYED IN THE FORM OF DROPS

6-HOT STEAM

7-REMAINS OF THE WASH

8-HIGH VOLATILE ALCOHOL

9-PURE ALCOHOL

10-LESS VOLATILE ACOHOL

—         Most of the spirits made today are distilled using the continuous still as this still is much faster and cheaper than the pot still.

—  A steady stream of “wash” enters the still and alcohol continuously exits the still. Since there is no “break” in the production of alcohol, the still is called as continuous still.

—  A continuous still comprises of two separate columns called as the Rectifier {2} and the Analyzer {1}.

—   Cold wash continuously enters the rectifier column at 3 and as it passes down through the pipes it is heated by rising hot vapours. The heated wash still in the liquid form exits the rectifier near the base and enters the analyzer at the top from 5.

—  It is sprayed down in the form of drops. Hot steam entering from 6 meets it and causes the volatile component {alcohol} to evaporate. Alcoholic vapours exit the analyzer at 4.

—  Meanwhile the water part of the sprayed wash collects at the base and is removed through 7.

—  The alcohol rich vapours enter the rectifier near the base. These vapours are at a temperature of 100°C.

—  As they rise up they meet cold wash, which is flowing downwards through the pipes. The hot vapours get condensed. The less volatile components condense first near the base of the rectifier.

—  They are called as “feints”. They are again introduced into the analyzer for further distillation. As we go up in the rectifier column the alcohol strength keeps on increasing.

—  Near the top, a cold radiator condenses the pure alcohol vapours which are collected separately at 9. Only the very volatile components of the distillation which have a high percentage of alcohol {other than ethyl} do not get condensed by the radiator and pass out through 8.

Alcohol Proof  System

—  The concentration of alcohol in a beverage is usually stated as the percentage of alcohol by volume (ABV) or as proof.

—  Alcohol by volume (abbreviated as ABV, abv, or alc/vol) is a standard measure of how much alcohol (ethanol) is contained in an alcoholic beverage(expressed as a percentage of total volume).The ABV standard is used worldwide.

—  In some countries, alcohol by volume is referred to as degrees Gay-Lussac (after the French chemist Joseph Louis Gay-Lussac).

—  Alcohol proof is a measure of how much alcohol(ethanol) is contained in an alcoholic beverage. The term was originally used in the United Kingdom and was defined as 7/4 times the alcohol by volume (ABV).

—  Another way of specifying the amount of alcohol is alcohol proof, which in the United States is twice the alcohol-by-volume number while in the United Kingdom it is 1.75 times the number (expressed as a percentage). For example, 40% abv is 80 proof in the US and 70 proof in the UK

—  The European Union follows recommendations of the International Organization of Legal Metrology (OIML). OIML's International Recommendation No. 22 (1973) provides standards for measuring alcohol strength by volume and by mass. A preference for one method over the other is not stated in the document, but if alcohol strength by volume is used, it must be expressed as a percentage (%) of total volume, and the water/alcohol mixture must have a temperature of 20°C (68°F) when measurement is done. The document does not address alcohol proof or the labeling of bottles