Distillers always strive to make the best possible spirit products and deliver the optimum taste and aroma experience for consumers. It’s a meticulous art where everything from the raw materials to the final matuation can dramatically affect the final quality. However, despite their best efforts, spirit producers sometimes encounter taints and faults in their final products. These unwanted flavours or aromas can significantly downgrade the product’s appeal for the consumer.

Common faults that derive from production issues include excessive oxidation (leading to flat or dull flavour), sulfides that add an undesirable ‘vegetal’ or ‘eggy’ aroma and high fusel oil content (compounds such as propanol, butanol and amyl alcohols that create harsh, solvent-like flavors and aromas). Taints often refer to the introduction of unusual and/or unwanted compounds from external sources, often through poor hygiene practices, impurities in raw materials or inadvertent contamination of the spirit during processing. Common examples include ‘musty’ or ‘mouldy’ characters from poor storage conditions or cork taint (e.g. geosmin, trichloranisole) and sourness due to bacterial contamination during the fermentation process.

It is important to remember that individuals have different abilities to perceive taints and faults, meaning that some tasters will find it much harder to detect and identify certain compounds compared to others. Some may also have an inherent (genetic) inability to smell or taste certain taint or fault compounds, so relying on the abilities of one distiller, or even a small group, to spot these problematic compounds can pose some risk to product quality.

Often a combination of chemical and sensory analysis techniques are required to provide quality assurance for spirit samples and to ensure that no unwanted aroma or flavour compounds are evident. Sensory analysis, in particular, is an extremely useful approach for identifying an unusual or undesirable aroma or flavour in a spirit. At Affinty Labs, we use trained panels to provide consistent and objective asessment of products and to define the unique aroma and flavour profile of each spirit. A range of chemical analysis techniques can then be used to quantify the concentrations of any taint or fault compounds, which is particularly useful for troubleshooting and product remediation.

Selecting high-quality raw materials and meticulous attention to detail, especially during fermentation and distillation, can help in minimising the frequency and impact of these unwanted compounds. It’s about making smart choices at every step of the process and using targeted quality control measures to maintain the spirit in optimum condition, until that first sip.