Science of Distillation: Can Grain Variety and Environment Lead to Finer Spirits?


A man drinking a glass of whiskey. Image by Tim Sandle.

Terroir is a term derived from the French language, where it is used to describe environmental factors that alter the expression of a crop such as barley (phenotypic characteristics). These factors can be important as they allow the crop to adapt to different habitats. These factors also influence the agricultural practices needed to obtain an optimal crop.

Under these conditions, where scientific approaches are practiced, the word “terroir” also applies to the general character of the crop and its intended end product. With this, some winemakers refer to the terroir of a wine made with specific artisanal vines or mezcal distillers can apply it to agave.

With the development of alcoholic beverages, the terroir is most used with French wine, especially with the controlled designation of origin (AOC). Many French viticulturists consider that the land from which the grapes are grown confers a unique quality that is specific to this place of cultivation.

Not everyone accepts the use of the concept of terroir (especially those who consider terroir mainly as a marketing strategy), although there are a growing group of supportive scientific research within the wine trade.

It is uncertain whether the concept can be applied to other alcoholic beverages, although a recent scientific paper (2021) has studied the possibility in relation to whiskey. This was discussed during June 2021 at a Tomoka tasting session this journalist attended and there was a consensus, no doubt, that has merit in the approach and its application to whiskey.

The basis of the study is that barley variety and its geographical location of growth can shape the taste of a spirit. To explore this, brand new laboratory-scale branded liqueurs were produced using two different barley varieties (called Olympus and Laureate). These varieties were grown in two different environments in Ireland (one in County Kildare and the other in County Wexford).

The study was conducted for two consecutive years (2017 and 2018), led by the Teagasc Food Research Center with the support of the Waterford Distillery (Republic of Ireland). After distillation and a period of maturation, the chemical composition of the spirit samples was examined. by mass spectrometry by gas chromatography. This technique is used to identify different substances within a test sample.

The analysis revealed about 42 volatiles present in the samples, and of these eight were considered particularly influential in the aroma of the brand new spirit. These include chemicals that are essential to the taste and aroma of whiskey: ketones, aldehydes, terpenes, sulfur, and furan compounds. These correlated with barley variety, the environment, and their interactions during the two seasons.

In relation to the concept of terroir, the interaction of variety plus the environment had a more significant impact than variety alone.

The results therefore suggest a “terroir” impact on the taste of the newly created spirit and therefore a potential importance for the production of individual malt whiskey. This is something that will require further research, especially in relation to the degree to which the aroma, initial taste and sensation on the drinker’s palate are perceptually different from the degree to which more liquors can be produced until they have sufficient public appeal. .

The research appears in the magazine Food, that the research work entitled “The Impact of Terroir on the Flavor of Single Malt Whisk (e) and New Make Spirit”.

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