There are several methods of producing gin. The European Community Regulation 110/2008, which governs spirit drinks, defines three:
- The first and most important is London Gin which is produced by the traditional method described below. Plymouth gin is made in a similar manner.
- Secondly, gin can be made from any spirit alcohol made from an agricultural product which meets the neutral alcohol requirements laid down in the spirit drink regulation. The neutral alcohol must be distilled to a minimum of 96% abv and the residues must not exceed those stated in the neutral alcohol definition. The finest raw materials for this ‘neutral’ spirit are either grain (normally barley or maize) or molasses. The best neutral alcohol has no flavor at all.
- Thirdly, gin can be produced by simply flavoring suitable alcohol with flavoring substances which give a predominant taste of juniper; this method is technically known as ‘compounding’.
The flavoring ingredients are all-natural and are referred to as ‘botanicals’. The type and quantity of each producer’s botanicals vary according to their own closely guarded recipes; all are carefully selected and tested for purity and quality. All gins include juniper as an ingredient: other botanicals used are coriander, angelica, orange peel, lemon peel, cardamom, cinnamon, grains of paradise, cubeb berries and nutmeg. Typically a fine gin contains six to ten botanicals. Like all gins, London gin should have a predominant juniper flavor.
The detailed processes for the distillation do vary between producers. In most cases, the spirit is diluted by adding pure water to reach the required strength of about 45% ABV. This is pumped into a still normally made of copper and the flavoring ingredients are added to it and it is then left to steep. Some producers place the botanicals in a tray over the spirit.
The still is heated, using a steam coil or jacket, to remove from the botanicals the essential oils (less than 5% of the weight) which give the flavoring to the spirit. The first distillate ‘runnings’ are re-circulated until an appropriate standard and strength (over 90% ABV) is reached. The lower quality early part of the run (‘foreshots’) and end of the run (‘feints’) as judged by the skill and experience of the ‘Stillman’ are run off to be redistilled.
Only the ‘middle run’ is used to produce high-quality gin; this is run off at about 80-85% ABV. The product then goes through a quality control ‘Tasting Panel’ and may also be analyzed by gas chromatography to ensure that it meets the required specification. This ensures product consistency. Only further neutral alcohol, water, and a minute amount of sugar can be added after distillation.
Distilled gin is made in a similar way to London gin. Production differs from London in that it is permitted to add further flavorings, both natural and artificial.
The gin is then brought to the required EU legal minimum alcohol level – at least 37.5% ABV to meet EC regulations, although some gins have a higher level – by the addition of pure demineralized water. It is now ready for bottling as it does not require any period of maturation.
The last method is a cheaper method of producing gin. Essential oils are either extracted from botanicals by distillation or pressed out. These are added to the appropriate water. The product of this ‘cold compounding’ may be called ‘gin’ under EC rules but not ‘distilled’ or ‘London’ gin.
This process used to be used to ensure that the quality of the alcohol was satisfactory before the distillation process took place. Advances in the production of neutral spirit have made this process unnecessary.