How Are Spirits Made?
Behind the bottle of fine spirits that you enjoy are centuries of skill, culture and tradition.
That skill, culture and tradition are poured into the three stages that go into making of a spirit: fermentation, distillation and post-distillation (aka maturation, filtration, blending, packaging).
Fermentation is how consumable alcohol is created. It's the process during which yeast converts sugar into alcohol and carbon dioxide. Put very simply, yeast and water are added to raw organic material and the yeast converts natural sugars from the plant into alcohol.
Yeast + Sugar = Alcohol + CO2 (+ Congeners)
Raw organic material (think grapes or other fruits; cereals such as wheat, barley, rye or corn; potatoes; sugar cane) is ground to remove its husks or skins. It's then mixed with water to produce a mash and finally yeast is added to begin fermentation. When the fermentation process is complete you're left with the wash – a mixture of weak alcohol, water, mashed raw material, waste products and congeners.
The next step is distillation. This is the process of heating the wash to separate and concentrate the alcohol – and it all comes down to temperature. While the boiling point for water is 100°C, alcohol boils at 78.4°C so when the wash is heated the alcohol turns to vapour before the water does. The vapour is collected and cooled.
Basic distillation apparatus consists of three parts: the still for heating the liquid, the condenser for cooling the vapour, and the receiver for collecting the distillate.
After distillation we are left with a clear, colourless liquid and a number of ways of adding colour and flavour to it. Storing (or ageing) the spirit in oak barrels will not only impart additional flavours but also colour. The longer the spirit is stored in the barrel the deeper the colour will be (although sometimes the colour is helped along by the addition of caramel colouring). The choice of cask material will play a large role in the flavour and colour of the resultant spirit – whether the cask is new or reused, charred or uncharred, heavily charred or lightly charred, large or small.
Another way to change the flavour of the spirit is through filtration, e.g. filtering the spirit through activated carbon. This is usually done on neutral based spirits like vodka or gin.
Flavouring can also be added to the spirit. Liqueurs usually have their flavouring added after distillation but some flavoured spirits are flavoured during distillation by adding the flavour (e.g. lemon) to the mash.