Chromatography Investigates the Role of Terroir in Whisky

Peaty, woody, floral and fruity are just a few of the words that can be used to describe the flavour of a malt whisky. There are many factors that contribute to the taste of whisky; type of grain; how it is processed through the malting and mashing stages; the distillation process; and finally, the type of cask used in the maturation process.

But research published in the journal Foods indicates that there might be more to the flavour of whisky than was first thought. Research by scientists in Ireland suggests that geographical growth location make a significant impact on the flavour of whisky. The research, published in a paper - The Impact of Terroir on the Flavour of Single Malt Whisk(e)y New Make Spirit - used gas chromatography to show that terroir makes a difference.

What is terroir?

For years the wine industry has used terroir to describe subtle differences between wines and help to place prestige on certain vintages. A certain flavour or character of wine can be subtly different from a similar wine. And the researchers behind the paper referenced above believe the same to be true for whisky. And it is all to do with terroir.

Terroir is a French term that is used to describe the environmental factors that can affect the flavour of wine. A dictionary definition might include the term ‘the complete natural environment’ in which a wine, or other foodstuff is produced. The concept can be applied to coffee, cider, chocolate, and cannabis and includes the interaction between soil, climate, micro-climate, exposure, and orientation. It varies from place to place. Not just by region, but by farm and field too. It is the reason why some vintages of wine are more celebrated than others. And it applies to whisky too.

Sunshine and soil make the flavour

The study reports on two barley varieties grown on separate farms with different environments in County Kildare and County Wexford in South Eastern Ireland over a period of two years. Each sample was malted and distilled to make a total of 32 different whisky distillates. The samples were then analysed using trained sensory experts and one of the very best analytical chemistry techniques – gas chromatography-mass spectrometry-olfactometry. The following article discusses the use of gas chromatography, Gas Chromatography Troubleshooting Part I – Peak Shape Issues.

The study identified more than 40 flavour compounds with half of them influenced by the terroir of the barley. The sheltered inland site had soil with higher pH levels and increased calcium and magnesium. The environmental factors included higher temperatures and lower rainfall. It made a whisky characterised by toasted almond and a malty biscuit finish. The exposed site had lower pH levels and increased iron and copper in its soil, it was more exposed and had volatile weather. It made a lighter, more floral whisky.

So next time you taste a dram, see if you can taste the sun and soil.