Scientists uncover source of ‘tropical’ malt whisky flavours

By Oliver Catchpole

Published: 12 August, 2026

Researchers working at Heriot-Watt University have identified some of the chemical compounds behind the mango-like aroma found in some Scottish and Irish whiskies.

PhD student Takehiko Hiura analysed 14 different whiskies from both countries, finding that aldehydes and acetals – common substances in such drinks – can increase these ‘tropical’ aroma properties.

These compounds are produced during both the fermentation and ageing processes.

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Commenting on the paper, professor Annie Hill from the university’s International Centre for Brewing and Distilling (ICBD), said: “Fruity notes like banana, apple and pear have long been linked to esters, which are produced during fermentation. But we didn’t know where the mango flavour was coming from - and now we do.”

This will be of interest for whisky makers – in his introduction, the researcher, Hiura, noted “demand from spirits producers for an increased understanding of the flavours influencing product aroma profile”.

This is because “distinctive product characteristics aids brand recognition, which is of particular importance in growing and crowded markets”.

Tropical fruit aroma has not been the focus of whisky research previously, although similar scents in both wine and beer have both been investigated.

The study revealed that one whisky contained particularly high levels of three key chemicals – isoburyraldehyde, isovaleraldehyde and isovaleraldehyde diethyl acetal.

When added to another low-mango-aroma drink, the level of scent increased significantly – potentially giving producers the ability to increase or tone down this feature of their whiskies.

Under the conditions of the experiment, this impact appeared to be to the mango scent, with little impact on other aromas.

Dr Calum Holmes, also of the ICBD, added: “The compounds that we found contributing to tropical notes, the aldehydes and acetals, aren’t new to whisky, they’re well understood.

“For whisky producers, that’s good news: it means they can hopefully dial up or tone down tropical aromas by manipulating existing process steps.”

The research was reported in the Journal of the American Society of Brewing Chemists, which ‘aims to bridge the gap between fundamental and applied research in the fields of brewing, distilling, winemaking, fermented beverages, and other closely interrelated disciplines’.

It was conducted in collaboration with Japanese drinks giant Kirin, which produces beers, wines and whiskies, among other things.

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