The process of Scotch Malt Whisky making

        Malting               Fermentation        
      The Kiln             Distillation      
      Milling and Mash             Maturation      

The malt whisky production process begins in the malt barn. Barley, which has previously been steeped in water for 2 days, is spread out over the floor and allowed to germinate for 5-7 days. During germination, the starch in the barley becomes soluble, thus preparing it for conversion into sugar. Throughout this period the barley must be turned at regular intervals to control temperature and rate of germination.

The starch in the barley is now converted, via a natural process, into soluble sugars.

Today there are only a few distilleries that have their own malt barns, Bowmore Distillery being one of them. The majority of the distilleries have their malted barley produced commercially to their own specifications.


The Kiln


Once the barley has reached the desired stage of germination, the green malt is transfered to the kiln mesh floor where it is dried to halt the germination process. Heat and smoke billow up from beneath the kiln floor and filter through the green malt. When this drying is complete, the barley is said to be malted. Peat is burnt to impart the unique smoky flavour into the moist green malt. The malt takes on a wonderful smoky smell and taste.


Milling and Mash

At the end of kilning, the malt is ground to a powdery substance called grist. Around 8 tonnes of grist is poured into a mash tun where it is mixed with hot water at a temperature of 63.5˚C. This infusion allows the soluble starch in the grist to be converted into a sugar solution. The solution, known as worts, is drawn from the mash tun and transferred to the washback for the next process. A further two waters are added to the mashtun to complete extraction. The third water is used as the first water for the next mash.

The remaining husks of barley, known as draff, are removed and used as cattle feed.

The sweet wort is transferred into a wooden washback. The total amount collected is 40,000 litres. Yeast is added which starts a natural process converting the sugar into alcohol. Fermentation takes approximately 48 hours. The fermented wort, now known as wash, has an approximate strength of 7% alcohol, and tastes like a sweet, smoky beer.

At Bowmore the six washbacks carry the names of former owners of the distillery:
Simpson (1779-1836)
Mutter (1837-1892)
Holmes (1892-1925)
Sherriff (1925-1950)
Grigor (1950-1963)
Morrison (1963-1994)


Malt Whisky is traditionally distilled twice, the first distillation taking place in the wash still. The wash is transferred from the washback into the wash still. Steam filled coils heat the liquid until the alcohol becomes vapour and rises up the still, over the swan neck and into a condenser, where the vapour is then condensed back into a liquid known as low wines.

The low wines are directed through the spirit safe, where the strength and temperature are monitored by the stillman. It then passes into receiving vessels. The collective low wines average strength is 20% alcoholic volume.


The low wines then pass onto the spirit still for a second distillation. The top fractions of the spirit (known as foreshots) and the end (known as feints) then pass into the feints received, ready for the next distillation to take place. Only the 'heart' or the middle cut of the spirit is collected as new spirit to be drawn off into casks for maturation.

The spirit and sample safe is the only means by which the stillman can monitor the strength and temperature of the spirit, allowing him to determine when the spirit is of a suitable quality.


The new spirit is then drawn off into casks for maturation.
There are different sizes of casks.


Quarter 125-Litres

    Bourbon Barrel 200-Litres     Hogshead 250-Litres
Puncheon 500-Litres     Sherry Butt 500-Litres     Port Pipe 550-Litres

The use of these photos: curtousy of Whiskyworld Van Wees, Amersfoort, The Netherlands (Thanks Mark).




The new spirit is drawn off into oak casks, which have been specially selected by the master blender.

These casks are stored in cool, dark warehouses where they breathe, taking in some of the characteristics of the enviroment in which they lay. At Bowmore, the seawater, battering against the cellar walls, is strong determinant in the flavour of our whisky. A proportion of the whisky in each cask evaporates annually. This is known as the "Angels' share".

Whisky can only be called Scotch Whisky if it is distilled and matured in oak casks for a minimum of three years in Scotland, but many of the casks that are filled at Bowmore lie in the warehouse for many more years before bottling.



Click and watch a YouTube video (3:42 min.) of Morrisons Bowmore bottling plant
(courtesy of Erik de Vries, The Netherlands)


Former Bowmore distillery manager Ian 'Percy' McPherson (untill 2006)
Bowmore distillery manager Eddie MacAffer (2006-2015)
Whisky Distillery Manager of the Year 2013 (click to read more)
Bowmore Distillery manager David Turner in the famous Bowmore No.1 Vaults
Read more about Bowmore Distillery manager David Turner


  Updated 16-12-2018


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