What does the term ‘complexity’ mean in the world of wine?

Many people talk admiringly about the complexity of wine. However, it is often unclear what exactly they have in mind when using the term. In this review, we summarize why the appealing notion of chemical complexity is presumably not what is being referred to. Instead, we argue that a more plausible explanation is in terms of perceived complexity. It would appear that some writers use the term ‘complex’ upon tasting a wine that exhibits a number of distinct, yet harmoniously-balanced, elements that may be experienced over the course of a single prolonged mouthful, over a glass, or over the lifetime of the wine as it ages in the bottle. However, another use of the term that has emerged from studies conducted on both experts and social wine drinkers relates to a single unitary perceptual experience of complexity. Perhaps, though, the latter account is better described as inferred rather than directly perceived complexity. Ultimately, according to the evidence that has been published to date, it would appear that different groups of consumers use the term ‘complexity’ consistently while, at the same time, describing something different in, or about, the wine. We focus, in particular, on differences in the usage of the term between wine experts and social wine drinkers.