The taste of barley

Most of us know that Whisky is made from barley. Anyone who has ever looked around in the knowledge section on our website also knows what happens to the barley before it can become Whisky: Malting, mashing, fermenting, distillation, cask maturation - the process is straightforward. Most of the Whisky taste is created during the maturation in casks - except for peated Whiskies, where peat smoke in the malting process plays a major role. It is not so clear, however, what influence the original barley has on the taste of the Whisky. After all, the knowledge of malt production is not very widespread. We explain the process using the example of the Speyside distillery Glenfarclas.

In earlier times, barley was denied any influence on the taste of the final product Whisky. However, all barley varieties contain esters which provide the Whisky with aromas. Analyses have revealed quite different contents of esters in the individual barley varieties. The cultivation period also has an effect on the quality of the grain: Winter barley (sown in autumn) has a higher protein content than spring barley (sown in spring), which is why the latter is used more often. In terms of taste, the protein content should not exceed 10.5%, otherwise the 'beer' will turn out too bitter. Spring barley is therefore the barley used in Europe for the production of alcoholic beverages, i.e. beer, Whisky or other spirits. Due to the longer vegetation phase and the effective use of winter moisture, the yields of winter barley are higher and its nutrients advantageous for the use as animal feed. Newer winter barley varieties with high protein and fibre contents are grown only for human consumption. Among other things, it is used for the production of Bourbon. Proteins give Whisky a slightly tangy taste, while starch makes Whisky sweeter.

The spring barley for Glenfarclas Single Malt is normally grown in Scotland and often in the Moray area, where most of the barley for Scotch Whisky comes from.

Malting (steeping, germination and drying)

The harvested barley is first soaked in water to start the germination process. Barley varieties such as Chariot and Optic are popular because of their germination rate of 98% and their low nitrogen content (less than 1.6%). The nitrogenous degradation products of the protein cause undesirable bitter flavours in the end product. During germination, the starch in the grain is converted into a soluble form and enzymes are released. These enzymes break down the starch into sugar during mashing.


The barley is soaked in water for 24 to 36 hours. In modern plants, the water is temporarily drained during the process and air is blown through the barley to remove carbon dioxide and restore the oxygen supply. Steeping increases the moisture content of the barley to about 46% and triggers the germination process.


The barley expands and enzymes, a group of complex proteins produced by living cells, are formed. These enzymes act as catalysts in specific biochemical reactions and are needed to break down the starch into fermentable sugars.

Tempered, humidified air is blown through the germinating barley. The air is used for temperature control, while humidification minimizes moisture loss to 3-4%. The moisture content of this 'green malt' affects the development of all important enzymes.

As the barley grows, the plant hormone Gibberellic acid induces the synthesis of hydrolytic enzymes. The enzymatic hydrolysis (a chemical reaction in which a compound reacts with water to produce other compounds) of proteins and beta-glucans, i.e. sugars, in the starch-containing endosperm (the tissue within the barley) converts the hard endosperm of barley into the soft endosperm of malted barley, which can easily be ground to grist during the milling process. In short, the barley becomes softer and sugary, making it easier to grind and ferment.

Drying or kilning

The 'green malt' is carefully dried over a period of 24 to 48 hours to stop germination and reduce the moisture content from 43% to the required 4.5%. It is important to preserve the enzymes released by germination during mashing. These are necessary to enable the final conversion of the starch into soluble, fermentable sugars.

During kilning, in turn, complex chemical reactions take place. Amino acids and sugars are broken down or react together to produce characteristic roasted, malty flavours in the barley.

Finally, malted barley contains more endosperm-degrading enzymes than unmalted barley, as well as more soluble proteins, amino acids and more colouring compounds. This results in a higher yield of malt sugars and amino acids during mashing and a higher yield of alcohol during fermentation.

Enough technical jargon: Opinions differ as to whether the barley really does have a major influence on the taste of the final product Whisky. It can probably be agreed that proteins and starch give the Whisky different flavours and that the content of esters also has an influence on the taste of Whisky. Later in the production process, during fermentation and cask maturation, more flavours are created in the Whisky. And in the end it is the Whisky in the bottle that counts!