Brewing is the first step that will launch the elaboration of the whisky. Indeed, the grist (= the crushed malt) will be mixed with hot water in order to extract the starch. The enzymes contained in the grist (proteinases and peptidases) will then transform the starch into less complex sugars (dextrose and maltose) that can be assimilated by the yeasts during fermentation.
The brewing is done in 3 successive waters :
The spent grain, a waste product of the brewing process, is generally intended for livestock.
Fermentation is the step that will roughly serve to transform sugar into alcohol by a reaction called alcoholic fermentation, which is made possible by yeast.
What is yeast? It is a unicellular micro-organism of the fungi family and is capable of causing the fermentation of animal or vegetable organic matter. Fermentation is a transformation, in general, of carbohydrates into acids, gases, or alcohol to extract part of the chemical energy while re-oxidizing the co-enzymes reduced by these reactions.
Fermentation will therefore serve to transform our sweet wort into a light alcohol, a malt beer.
Two types of yeast can be used: natural yeast or cultured yeast.
Natural yeasts are those naturally present in our environment, they have a strong aromatic potential; however, they are nevertheless very fragile, which makes their use very risky. Some brewers use them, however, the majority of breweries and distilleries prefer to rely on cultured yeasts which are more reliable and often used in a complementary manner. Cultured yeasts will make it possible to know the alcohol yield in advance, but also to be able to develop an aromatic palette specific to the types of whiskies sought after.
The wort is then placed in fermentation tanks and the yeasts are added. The yeasts will then begin their work and use the sugars to transform them into alcohol molecules. The fermentation heats up the wort, which then starts to bubble and the temperature rises. In order to prevent the temperature from rising too high, stirrers are started. The rise in temperature could inhibit the yeasts and the fermentation could then stop.
After fermentation, the resulting liquid is a malt beer that usually has a strength of between 6% and 8% vol. This liquid is called the wash and will be transported to vats to be stored there while waiting for distillation.
Yeasts are largely used to enrich the aromatic palette of whiskies,which is why the types of yeast used by distillers are often jealously guarded secrets.
Indeed, it is during fermentation that the esters (aromatic molecules) are created, and characteristic notes of apple, pear, banana, but also floral notes, or cereal odors appear.
Distillation, a primordial step for any whisky making, starts with the choice of the still (type, shape).
There are different types of stills, indeed, we have :
This type of alembic still is widely used in the elaboration of grain whiskies.
Why are the stills made of copper? The stills have not always been made of copper. In fact, a few centuries earlier, stills were made of so-called malleable materials such as ceramics or glass. However, copper proved to be the most suitable material for this type of process because copper is relatively easy to model. In addition, it conducts heat very well and is very resistant to corrosion. Copper also insulates the volatile sulphurous substances inside the still and thus promotes the development of esters, aromatic molecules.
Indeed, the more contact there will be between the vapors and the copper during condensation, the more fruity and aromatic the distillate will be.
Distillation is the step that will concentrate and purify the alcohol contained in the wash. The wash will first be put in a first alembic still called wash still. This is a large capacity still that will first allow to go from a wash of 6% vol. to 8% vol. to a liquid that we call low wines titrating between 25% vol. and 35% vol.
Once the wash is introduced, the liquid is heated, which will create vapors, these vapors will then be condensed and stored in an alcohol box called spirit safe, which will allow the distiller to measure the density of the alcohol.
The low wines are then sent to a second still, the spirit still, of smaller size, and a second distillation is then started.
The condensed vapors are separated into 3 parts: the head, the heart and the tail. The head and the tail are impure and will be redistilled with the next distillation of the low wines, in order to make the most of the low wines.
The heart is the limpid part, the most interesting for the production of whisky between 68% vol and 75% vol.
Generally, whisky distilleries proceed in double distillation, however some proceed in triple distillation. The triple distillation brings lightness and fruity and floral notes in finesse.
The toasted toast is then aged in oak barrels in order to acquire the final aromatic and chromatic (color) palette of the spirit.
Different types of casks can be used for ageing :
Depending on the type of cask, the aromatic bouquet of the whisky will develop differently. Indeed, thanks to the chemical reaction between the alcohol and the wood, this will allow the release of aromas that will contribute to the taste but also to the color of the final whisky.
The art of assembly is specific to each house. The blending allows to obtain a constant taste and this is done thanks to the mixing of different barrels. One can thus blend several casks from the same distillery (=genesis), or mix single malt with grain whiskies (= blended scotch), or blend single malt from different distilleries (= blended whisky), or mix whiskies of different ages. In the latter case, it is the age of the youngest cask that determines the age of the product (for example, on the label, 16 years old means that the youngest cask used for this blend has 16 years of cask ageing).
Dilution is the last step before bottling. This is done with pure spring water added in alcohol. This dilution makes it possible to lower the alcoholic degree of the spirit after ageing.
The cask crudes refer to spirits that have not undergone this dilution, i.e. after leaving the cask, they are directly bottled.
In French, the word whisky or whiskey is differentiated by the places of manufacture of these malted spirits. Indeed, the word whisky, spelled without the "e", designates a production coming from Scotland, Canada, Japan, and other countries of the world. The word whiskey, spelled with the "e", refers to Irish or American production. However, this rule cannot apply to all languages.