Technology of whiskey production: 8 stages
The whiskey production process, regardless of the region of production, consists of eight stages.
According to this scheme, whiskey is made in Ireland, Scotland, the USA, Canada, Japan and other countries.
Preparation of malt for whiskey
Barley (rye, wheat, corn) is cleaned from debris and illiquid, dried.
Grain is poured with water, laid in a thin layer until sprouts appear. After 7-10 days, proceed to the next stage.
If the grain does not go through the mashing stage, the whiskey produced from it will be called grain. It is practically not sold in its pure form, but is used to create blends.
Drying malt for whiskey
Malt is dried in different ways in different regions. In Japan and Scotland, smoke from burning peat, charcoal and beech shavings are used for this purpose.
The result is the so-called "smoked grain". It gives the finished product a smoky-peaty character with notes of iodine.
It is noteworthy that the Japanese buy peat from the Scots in an effort to get closer to the standard.
In Ireland and other countries, drying is carried out without the use of smoke. The exception is Cooley Distillery.
Production of wort for whiskey
The dried malt is ground to a state of coarse flour (grist), combined with hot water and allowed to brew for 8-12 hours, stirring regularly.
In this way, malt wort is obtained, which is a sweetish light white slurry with a strong grain aroma (wort). After the flour is properly dissolved, the mixture is cooled.
Fermentation of the future whiskey
To activate the fermentation, specially cultivated strains of pure yeast are added to the wort, the mass is mixed well until it is evenly distributed and the mixture is sent to the fermentation tanks.
Fermentation lasts on average 2-3 days at a constant temperature of 35-37 °C.
The result is a low-alcohol mash (wash) - a beverage resembling beer with a strength of about 5%.
Whiskey distillation
The mash is distilled twice (or three times) in copper pot stills, similar in shape to retorts.
Copper is used to make cubes and coils for a reason:
The material has excellent ductility, which makes it possible to make equipment of any shape from it.
It is characterized by high thermal conductivity, which ensures accelerated heating of the distillation tanks (and thus reduced costs) and their rapid cooling, which is necessary for high-quality condensation.
If open flame is used for distillation, even heat distribution is of particular importance: it prevents burning of mash particles (yeast sediment, malt flour lumps).
Positive effect on the quality of the final product.
Copper ions effectively bind sulfur, which, when interacting with alcohols at high temperatures, can form foul-smelling organic compounds (mercaptans).
For the same reason, the production of strong alcohol (cognac, tequila) is prohibited from sulfitizing the raw material.
During distillation in copper vessels, in contrast to distillation in tin or steel cubes, many aromatic compounds are formed that are necessary for a quality drink: aldehydes, esters, furfural, furan compounds.
In addition, a number of complex reactions (dehydration of pentoses, polymerization of sugars, melanin formation, etc.). д.), which results in the appearance of a dark amber hue and a whole range of flavors: nutty, vanilla, chocolate, caramel, spicy.
After distillation in the first tank (wash still) with a volume of 700-2300 dal, a liquid called "low wine" is obtained. Its strength: 25-30%.
Distillation in a second still (spirits still) with a volume of 600-2100 dal after separation of "heads" and "tails" gives whiskey with a strength of up to 70%.
The starting and ending fractions are merged into "low wines" and sent back to distillation.
The design of the stills significantly affects the taste of the product. In each distillery, the stills are made according to their own design, observing a certain shape and volume.
It is believed that the taller and narrower the container, the lighter and thinner the whiskey it produces.
When replacing the equipment, they try to reproduce the exact shape of the worn-out cubes, up to copying the smallest dents and bulges, so as not to "lose" the taste of the produced drink.
The main load during distillation falls on the upper part of the still ("swan neck") and the coil, which are in more contact with hot steam.
Whenever possible, they try to make a partial replacement, not dismantling the cube completely, but renewing the segments that have thinned out. Identify problem areas with ultrasound.
In addition to the classic "pot still", continuous distillation apparatus ("coffey still" or "patent still"), invented in 1831 by the Irishman Aeneas Coffey, are used for distillation. Such designs speed up the process by 15-20 times, but are used mainly to produce light grain spirits that are part of blends (blended whiskey).
The whiskey obtained during double (or triple) distillation is diluted with spring water to a strength of 50-63.5% and proceeds to the next stage.
Aging of whiskey
Distillates are aged in oak barrels for at least 3 years. The best containers are those that have previously been used to store sherry. The reuse of barrels used for importing Spanish wine was tested in the XVIII century in order to save money. The experiment proved successful and became part of the technology.
Nowadays, aging in sherry casks is a sign of high quality whiskey. Due to the lack of such vessels, American white oak barrels are used, which used to store bourbon.
An alternative option is to treat fresh containers with cheap sherry.
Interaction with wood gives whiskey its characteristic properties: it makes it darker, softer, and adds additional accents to the bouquet.
Tannins, lignins, vanillin and wood sugars contained in oak tannins, lignins and wood sugars formed during barrel firing give distillates a sweetish flavor and aroma.
The alcohols, aldehydes and esters that make up whiskey penetrate the wood pores, oxidize and form complex compounds.
The part of the distillate that evaporates during aging through the pores of the oak is poetically called the "angel's share" ("angel’s share", "la part des anges"). A similar process is observed not only during the maturation of whiskey, but also other alcoholic beverages: cognacs, rums, armagnacs, wines.
The amount of annual "divine losses" depends on the humidity and temperature of a particular area and is in the range of 1.5-7%. Based on these data, the recommended aging periods for different alcohol in a particular climate were determined.
In hot countries, beverages rarely mature in barrels for more than 10 years due to huge product losses.
Each area has its own whiskey aging traditions:
In America, alcohols mature exclusively in new containers.
In Ireland and Scotland, the distillate is aged only in used barrels (bourbon, sherry or port).
The vessels differ in size and shape. There are 6 categories of casks in Scottish distilling:
Butt - holds up to 110 gallons (approx. 500 liters)
Puncheon - the volume is the same as in the "butt", but the barrel itself is lower and wider
Hogshead - capacity: about 56 gallons (250 liters)
Barrel - with a volume of up to 40 gallons (approx. 180 liters)
Quarter - holds up to 30 gallons (127-160 liters)
Octave - the smallest cask, designed for 10 gallons (45-68 liters)
Spanish containers from Oporto are highly valued. Local port wine barrels are characterized by an elongated shape that resembles a cigar.
Blending whiskey
To create blended drinks (blends), 15-50 varieties of malt and 3-4 types of grain spirits of different ages are mixed separately. Two categories are combined into one and the mixture is kept for several more months.
Some blend recipes have a long history, while others are modern developments created on the basis of ancient technologies or from scratch in accordance with market demands.
The purpose of blending is to obtain a product of a certain quality by combining the best characteristics of different whiskeys in one drink.
The first blend recognized by the masses was compiled in 1853 by Andrew Usher. It was "Old Vatted Glenlivet".
A blending master has to solve two tasks at once when mixing different varieties of single malt and grain whiskey: to create a unique taste inherent in a particular brand and to monitor its constancy over the years.
Each spirit selected for the blend must be tasted not only after distillation, but also during the maturation process.
Two methods are used to produce blends:
Different varieties of malt and grain spirits are combined in special containers (egalizers), where they are aged for 1 day. The mixture is then poured into barrels, where it spends several weeks before being bottled. This is how cheap whiskey is made.
Several varieties of single malt whiskey are selected and combined with grain alcohols in egalizers. To improve the properties of the blend, a "marriage" ("wedding") of the components is carried out: the mixture is aged in oak for 6-8 months. This is how expensive whiskey of excellent quality is produced.
If the label of a blended drink indicates the aging period, it refers to the youngest spirit in the blend. Whiskey with a significant proportion of old single malt components is labeled "de luxe".
Bottling whiskey
Before bottling, the whiskey is passed through membrane or cellulose filters at a temperature of 2-10 °C. If necessary, the drink is diluted with spring water to the desired strength parameter.
Update: 05.05.2019
Category: Whiskey and Bourbon