The flavour of whisky is influenced by the soil, climate and natural features of the area where the barley is grown, a new study suggests.
The research indicates that the concept of terroir, which is usually applied to wine and cognac, can also be applied to barley and the single malt whisky spirit distilled from it.
This principle is well established in the wine industry, but has not been significantly studied in other alcoholic beverages.
In the study terroir is described as the set of all environmental factors that affect a crop’s phenotype, including unique environmental contexts, farming practices and the crop’s specific growth habitat.
The first paper from The Whisky Terroir Project examined two barley varieties grown on two farms with separate environments in 2017 and 2018 – Athy, County Kildare and Bunclody, County Wexford in south eastern Ireland.
Each sample of barley was micro-malted and micro-distilled in laboratory conditions to produce 32 different whisky distillate samples.
These were then tested by experts using the very latest analytical methods, as well as highly trained sensory experts.
According to the study, published in the scientific journal Foods, more than 42 different flavour compounds were found, half of which were directly influenced by the barley’s terroir.
The sheltered inland Athy site had predominantly higher pH levels with increased amounts of calcium, magnesium and molybdenum in its limestone based soil.
Researchers said it had consistent, higher temperatures and lower rainfall.
The spirit from this barley was characterised by toasted almond notes, and a malty, biscuity, oily finish.
However, the more exposed Bunclody site had lower pH levels with increased amounts of iron, copper and manganese in its soil, which is based on a shale or slate bedrock.
The farmland is closer to the coast and was typically subject to more volatile weather.
The taste here was lighter and floral, with a flavour of fresh fruitiness, according to the research.
Researchers say the study highlights the potential to produce single malt whisk(e)y with characteristics that are influenced by more than barley variety, production and maturation processes.
This creates the possibility of producing regionally specific whiskies in the same vein as wines.
Waterford’s Whisky Terroir Project was undertaken by an international team of academics from the US, Scotland, Greece, Belgium and Ireland.
They included Professor Kieran Kilcawley and Maria Kyraleou of Teagasc Food Research Centre, part of the Irish Department of Agriculture, Food and the Marine, Enterprise Ireland, Minch Malt.
It also featured cooperation from Scotland’s leading whisky laboratory.
Prof Kilcawley, principal research officer at Teagasc, said: “We utilised gas chromatography olfactometry which enabled us to discern the most important volatile aroma compounds that impacted sensory perception of the new make spirit.
“This research not only highlights the importance of terroir, but also enhances our knowledge of key aroma compounds in whisky.”
Mark Reynier, founder and chief executive of Waterford, said: “Barley is what makes single malt whisky the most flavoursome spirit in the world.
“This study proves that barley’s flavours are influenced by where it is grown, meaning, like wine and cognac, whisky’s taste is terroir-driven.
“Critics claimed any terroir effect would be destroyed by the whisky-making process, saying there is no scientific evidence to prove that terroir even exists.
“Well, there is now.”
Dr Dustin Herb, lead researcher and post-doctoral research at Oregon State University, said: “This interdisciplinary study investigated the basis of terroir by examining the genetic, physiological, and metabolic mechanisms of barley contributing to whisky flavour.
“Using standardised malting and distillation protocols, we preserved distinct flavours associated with the testing environments and observed year-to-year variations, indicating that terroir is a significant contributor to whisky flavour.”
The research was funded by Enterprise Ireland Commercialisation Fund in collaboration with Waterford Distillery.