Abstract

We don’t know much about the smells of the past. Yet, odours play an important role in our daily lives: they affect us emotionally, psychologically and physically, and influence the way we engage with history. Can this lead us to consider certain smells as cultural heritage? And if so, what would be the processes for the identification, protection and conservation of those heritage smells? In order to answer these questions, the connection between olfaction and heritage was approached in three ways: (1) through theoretical analysis of the concept and role of olfaction in heritage guidelines, leading to identification of places and practices where smell is fundamental to their identity, (2) through exploration of the evidence for use of smells in heritage as a tool to communicate with audiences; and (3) through experimental evaluation of the techniques and methods for analysing and archiving the smells, therefore enabling their documentation and preservation. We present this through the framework of Significance Assessment—Chemical Analysis—Sensory Analysis—Archiving. The smell of historic paper was chosen as the case study, based on its well-recognized cultural significance and available research. Odour characterization was achieved by collecting visitor descriptions of a historic book extract through a survey, and by conducting a sensory evaluation at a historic library. These were combined with the chemical information on the VOCs sampled from both a historic book and a historic library, to create the Historic Book Odour Wheel, a novel documentation tool representing the first step towards documenting and archiving historic smells.

Olfaction and heritage

The significance of olfaction in the context of cultural heritage, evidencing that smells can be fundamental in shaping who we are, where we belong and how we experience encounters with different cultures, has been recently examined in several case studies. They show that odour can be part of the local identity through history; that a central place for olfactory experiences in a culture results in a much wider vocabulary to discuss smells and that travel and tourism offer an opportunity to approach the world with our noses. However, the role of smells in our perception of and engagement with the past has not been systematically explored.

Odours are powerful triggers for emotions via the limbic system of the brain, which deals with emotions and memory. They are an effective way to evoke recollections; certain aromas can even act as part of the common memory of a generation. For example, people born before 1930 tend to display positive association with nature scents, and the fragrance of Playdough triggers nostalgia in those born after 1960. Scents can also influence behaviour: in shops, a pleasant scent positively impacts customers’ attitude towards the store, the evaluation of products and intention to revisit the place. A British company claims that treating customers with the smell of male sweat made them 17% more likely to pay their bills than a control group. Mood and cognitive function are also affected: although olfaction is one of the least considered senses in pedagogy, aromas can improve learning through their connections with memory, mood and productivity.

Smell as part of cultural significance

There is currently no strategy in the UK for the protection or preservation of smells. In heritage guidelines, odours are often recognized as a value associated with a place, or with certain practices. Currently, smells are viewed as an aspect of cultural significance, an overall measure of the value of a particular place to the public, as introduced by the widely adopted Burra Charter. Aesthetic value contributes to cultural significance and includes ‘aspects of sensory perception for which criteria can and should be stated’, and, as an example, ‘the smells and sounds associated with the place and its use’. In this sense, smell can be considered as an intangible property of tangible heritage and inextricably linked to it.

According to the guidelines published by the Historic Buildings and Monuments Commission for England (formerly English Heritage), the smells of a place are considered of value because they affect our experience of it. For this reason, they should be taken into account when defining the character of a historic area.

The connections between odours, locality, and identity are also a component of tourists’ experience. With globalization, we see that a location and the authentic experience of it are not always linked, because it is possible to have an experience that is perceived as authentic far from the original location. For this type of tourist, authenticity lies with the experience (existential authenticity), not with the place. Likewise, it could be said that reproducing historic or heritage smells without their original physical context would be looking to provide an existentially authentic experience.

Characterisation of smells

Since most odours are composed of volatiles organic compounds (VOCs), the analytical methods frequently involve headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC–MS). However, it needs to be stressed that not all compounds that could trigger the sense of smell can be determined using this technique. For inorganic compounds, and some organic compounds that are difficult to sample using SPME, other sampling and analytical techniques may be more useful, from direct detection to various types of separation techniques.

SPME was developed in the 1990s by Pawliszyn et al. and is used for extracting volatiles in the headspace over liquid and solid samples. It has been used successfully to extract and analyse VOCs from historic materials, including paper. GC–MS techniques are routinely used to analyse perfumes and cosmetic preparations.

The vocabulary we use to describe smells is important and it is essential that a methodology to describe odours for archival purposes includes a sensory description, in addition to the chemical one. In some industries, the human nose is the main tool to characterize odours due to its accuracy and sensitivity. Human olfactory experience depends on several factors, including genetic profile, ethnic background, gender, age, cultural background, and overall physical environment. The person’s mood at the time of sampling can also have an impact on description of the hedonic tone (pleasant/unpleasant) of the smell. Information on the evaluator and the evaluation circumstances can therefore be valuable metadata on the heritage smell.