Terroir in whiskey

New research has found evidence that the influence of soil, microclimate and topography on barley has an impact on the flavour of whisk(e)y.  

The concept of terroir – the French principle that the physical growing environment can influence flavour characteristics – has been a subject of much debate in the whisk(e)y industry, where often more emphasis is placed on production techniques over the spirit's principal raw ingredient. 

But a peer-reviewed paper, The Whisky Terroir Project, supported by Waterford Distillery, and published today in scientific journal Foods, claims that terroir can also be found in barley and, critically, the spirit distilled from it.

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 analysts and using gas chromatography–mass spectrometry–olfactometry (GC/MS-O), as well as sensory experts. 

More than 42 different flavour compounds were identified, half of which were directly influenced by the barley’s terroir.

The sheltered inland Athy site revealed higher pH levels with increased amounts of Calcium, Magnesium, and Molybdenum in its limestone based soil. It had consistent, higher temperatures and lower rainfall. Whisky new make spirit made from this barley was characterised by toasted almond notes, and a malty, biscuity, oily finish.

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. Whisky new make spirit made from this barley was lighter and floral, with a flavour of fresh fruitiness.

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The findings could lead to a new emphasis placed on the barley used for whisk(e)y production across Ireland and Scotland, which is not always grown locally. The East of Scotland and East of England grow most of the UK’s barley.

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.”

Mark Reynier, founder and CEO 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.”