Single Malt

The words can be therefore better expressed as “single-sourced” malt whisky (much like when wineries say “single-vineyard”). Malt refers to the process of Malting Barley (see below). Thus, all Single Malts have in common that they are made by malting barley in a single distillery. See also blended (or vatted) malts, Scotch single malt and blended scotch whisky. There are several basic steps to the process: malting, mashing, fermentation, distillation and maturation, although the minor elements may vary from one country or distillery to another.

Generally, whiskies of varying proof strengths and ages from different casks are mixed together, ensuring a consistent distillery product (as the product of any one distillation will inevitably not be identical to any other), although the age which appears on the label is always the age of the youngest distillation in the bottle. Single malts tend to be more expensive than blended whiskies since they offer the best that the distillery has to offer in terms of quality. Although blending has its advantages, single malts are unable to hide some imperfections and therefore producers usually put forward their best produce.

Barley is a native grain to Scotland and grows extremely well and plentiful in Scotland’s maritime climate. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Barley thrived better than other cereal crops in Scotland’s more challenging growing conditions. It was also easier to malt than other grains. Barley was also chosen over other grains (Rye, Wheat or Corn – Bourbon) because the early distillers in Scotland and Ireland preferred the end resulting taste over other grains, although a lot of these other grains have found their place in other whisky growing countries. There are a multitude of barley varieties, though the whisky industry tend to use the two-row variety over the 6-row (used in some beers, for example). Two-row barley, has a lower protein content than six-row barley, thus a more fermentable sugar content. However, the most important and defining characteristic is that the types of barleys used contain a mutation that blocks the production of compounds known to be harmful in food in the end product. There is a recent trend to use more “locally grown” barley (especially in Scotland) and more bio-diverse varieties to avoid mono-culturing.

Malted barley, or malt (Old English/Germanic), is barley that has been allowed to germinate (or sprout). On its own, a barley grain will malt, or sprout, as part of its natural life cycle. Whisky makers need this malted barley year round, so outside of the two months of spring where it happens naturally, the barley is therefore tricked into sprouting by being soaked in water. By doing this to the grain, the starches are converted into fermentable sugars. The process ensures that starch in the grain can be made into alcohol. Malted barley came to define the style and flavour of ‘malt whisky’.

The process begins when the barley is transferred to soak in tanks of water called barley steeps; this process takes two to four days. In the traditional process, the barley is then spread on a malting floor, to be turned by hand daily for the next twelve days or so, allowing it to sprout; now, however, most distilleries use mechanical devices for turning the sprouting barley. As the seeds germinate, the starch in the barley releases some of its sugars. At the appropriate moment, germination is stopped by drying the cereal in a malt kiln over a peat furnace or fire. The peat smoke which flavours the drying barley at this stage can, depending on its intensity, be tasted in the final whisky itself. The malt kilns traditionally had the pagoda-style roofs which were such an instantly recognizable characteristic of the malt distilleries; these can still be seen on older distilleries.

A sub-group of single malt whisky is the single-cask malt. These are whiskies which, as the name suggests, are the produce of one distillation, bottled straight from the cask and not vatted with any other produce from the distillery. This process, together with the absence of chill filtration before the whiskies are bottled, ensures that the particular character of a distillery’s whisky — and, indeed, of a specific distillation — is unmasked, and greatly emphasized. Supplies of a particular variety or distillation are, by nature, finite. This is often one of the the most expensive types of whisky, often costing at least double the price of a normal, distillery-bottled single malt, but felt by many whisky drinkers to be well worth the expense.

Another variation on single malts is cask-strength.. As the name suggests this is a whisky that has not been diluted with water. Sometimes this is a sub-group of the single-cask malt, however it does not necessarily have to be. Cask strength malts are gaining popularity as customers favour the unadulterated taste. Not for the faint hearted, as the expression goes.

A vatted malt is the final of the malt whisky sub-groups. This type of whisky has a long pedigree, having formed the basis of the first blended whisky in the mid nineteenth century. Vatted malts are normally produced by blenders and big companies who have a variety of malt distilleries from which to take their product. It could be regarded as a half-way house between a blend and a single malt, although the flavours in some vatted malts can be just as well developed as those in a single. Single malts of different distilleries and different ages are mixed together, the age (if any) on the label being that of the youngest whisky in the mixture.

References :

https://en.wikipedia.org/wiki/Barley
https://www.wordsense.eu/malt/
https://www.whiskyadvocate.com/why-and-how-barley-matters-in-whisky/
https://thewhiskeywash.com/whiskey-styles/american-whiskey/whiskey-flavor-by-grain-part-i-the-big-four/
https://distiller.com/articles/whiskey-grains/