Whisky and Terroir - Scientifically studied

Not all Whiskies are the same. For you as a Whisky connoisseur, this is not a novelty. There are many processes in the production that influence the taste and aroma of Whisky, such as the maturation in various casks (Sherry, Wine, Bourbon, etc.), the shape of the pot stills or the use of peat smoke to dry the malt. An often discussed and controversial topic among Whisky experts is the question of whether the 'terroir' of the barley, similar to the production of wine or cognac, also influences the taste of the resulting Whisky. The frequently voiced counter-argument is that the Whisky production process (distillation) destroys any influence by the terroir of the barley.

An international team of scientists from the USA, Scotland, Greece, Belgium and Ireland recently investigated this issue in detail. The so-called 'Whisky Terroir Project' published a study in February 2021, proving that 'terroir' has influences the taste of Whisky new make spirits.

 

What is Terroir?

Before we delve deeper into the scientific context, let us first clarify the question of what the term 'terroir' actually means. The French term cannot be translated one-to-one into English, but we can paraphrase it. The French principle that natural factors such as the microclimate of the soil and the weather together can influence flavour characteristics has long been accepted in other beverage categories such as Wine and Cognac. In the Whisky world, it has been a source of disagreement for years.

The Whisky Terroir Project has now addressed this controversial issue by publishing a scientific study in Foods magazine. Foods has been publishing studies from all areas of food research since 2012. The terroir article proves that terroir can also be found in barley, and - more importantly - even be tasted in the Whisky new make spirit distilled from it.

For this purpose, two different barley varieties (Olympus and Laureate) were studied, each in two different Irish regions: Athy, County Kildare and Bunclody, County Wexford. For the analysis, samples were taken from yields of two consecutive crop years (2017 and 2018). The samples were micro-malted and micro-distilled under laboratory conditions to produce 32 different Whisky spirit samples. These samples were then chemically analysed using gas chromatography mass spectrometry olfactometry (GC/MS-O) to detect olfactory active compounds. In addition, trained sensory experts tasted the samples.

Terroir in Whisky?

The project concluded that the samples contained 42 different flavour components (compounds), half of which were influenced by the terroir of the barley. Among them, eight compounds were very influential and 15 were 'only' influential on the taste of the spirit. Moreover, the evaluation showed that the combination of barley variety and its growing environment had a greater influence on the flavour of the distillate than the barley variety alone. There were also greater differences in the flavour of the distillate in relation to the year of cultivation of the barley variety than in relation to the variety alone. Thus, the study concludes that there is a 'terroir' influence on the new make spirit. In detail, this developed as follows:

  • The protected inland region of Athy has higher pH levels and higher amounts of calcium, magnesium and molybdenum in its limestone soil. There were higher average temperatures and less rainfall. The Whisky spirit produced from the barley grown in Athy is characterised by aromas of toasted almonds and a malty, oily finish with cookie notes.
  • The Bunclody region is more exposed to environmental influences than the protected inland region. The barley grown there has lower pH levels and higher amounts of iron, copper and manganese in the soil, which lies on a shale base. Located closer to the sea, Bunclody is exposed to more inconsistent weather conditions. The barley harvested there produces a lighter new make spirit with floral aromas and a fresh, fruity flavour.

It has thus been scientifically proven that different terroirs produce different flavours in new make spirit. For only the genetic physiological properties of the barley and their influence on the flavour of the distillate were studied here.

However, the study focuses only on the Whisky new make. But as we know, a Whisky is only officially 'Whisky' when it has been allowed to mature in oak casks for at least three years. During the maturation in the cask, the aroma changes substantially. Not only are certain flavours removed from the distillate during the so-called subtractive maturation. Additive maturation also ensures that the spirit absorbs aromas from the cask wall. In the case of casks with previous ageing (Sherry, Wine, etc.), these are also aromas from the Wines or spirits they previously held. During cask maturation, the interaction of the spirit and the wood also creates chemical compounds that contribute greatly to the aroma. Some Whisky producers even estimate that cask maturation accounts for 60-80% of Whisky flavour - Perhaps this is a topic for another scientific study.