The gradual development of analytical means for the assessment of flavour and quality may be used to monitor the process of maturation and/or to provide assistance for the blending of spirits, whether this be cognac or whisky. Analytical methods are also necessary for the detection of fraud and adulteration. A number of compounds from oak extract have been proposed as indicators of oak maturation, while the adulteration of distilled beverages, by adding vanillin,may be detected by the lack of correspondingly high levels of other wood-derived aromatic aldehydes or phenolic compounds [38, 39].