A Narrative Review of Sulfur Compounds in Whisk(e)y

Abstract

The production process of whisky consists of malting, mashing, fermentation, distillation and maturation. Sulfur volatile compounds generated during this process have long attracted interest because they influence quality in general. More than forty compounds have been reported: they are formed during malting, fermentation, and distillation, but some may decrease in concentration during distillation and maturation. In sensory analysis, sulfur characteristics are described as sulfury, meaty, cereal, feinty, and vegetable, among others. Their contribution to overall quality depends on their concentration, with a positive contribution at low levels, but a negative contribution at high levels. Chemical analyses of sulfur volatiles have been developed by using sulfur-selective detectors and multi-dimensional gas chromatography to overcome the numerous interferences from the matrix. Formation pathways, thresholds, and contribution have not been elucidated completely; therefore, methods for integrating diverse data and knowledge, as well as novel technical innovations, will be needed to control sulfur volatiles in the future.

The Elemental Fingerprints of Different Types of Whisky as Determined by ICP-OES and ICP-MS Techniques in Relation to Their Type, Age, and Origin

“…In this work, an interesting relationship between the sulphur concentration and the age of the analysed alcohol beverages samples was made and deserves attention. Sulphur volatile compounds generated during the production process of whisky, to a large degree, influence their quality [ 27 ]. On the basis of the research carried out so far, alkyl sulphides such as DMS, DMDS, and DMTS have been recognized as alcohol maturation markers [ 28 , 29 ].…”

Assessment of the Authenticity of Whisky Samples Based on the Multi-Elemental and Multivariate Analysis

“…Among the elements listed in Table 3 , for which the existence of statistically significant differences has been demonstrated, the presence of sulfur should be commented on. As reported in the literature data, sulfur volatile compounds generated during the whisky production process influence their quality to a large degree [ 68 ]. The selected alkyl sulfides (dimethyl sulfide (DMS), dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS)) have been recognized as age markers for whisky, as the level decreases with the time the alcohol spends in the barrel [ 69 , 70 ].…”

Provocation: prolonged maturation of beer is of unproven benefit

“…Moreover, aging periods involved in whisky production are generally far longer than would be involved in even the lengthiest maturation protocol in a brewery. Thus changes to sulphur compounds in whisky such as 3-(methythio) propanal, dihydro-2-methyl-3(2H) thiophenone, ethyl 3-(methylthio)propanoate, 3-(methylthio) propyl acetate, 3-(methylthio) propanol, DMS, dimethyl disulfide (DMDS), DMTS, 2-thiophenecarboxaldehyde, 5-methyl-2-thiophenecarboxaldehyde, benezothiophene, and benzothiazole occur over a timescale of years (usually at least three) rather than weeks or a few months (Masuda andNishimura, 1982, Wanikawa andSugimoto, 2022). Wang et al (2023) have recently published a review of the changes occurring during the ageing of several distilled beverages.…”