Cocoa, wood, rusks every book has a distinctive smell. And each smell says something about how and when it was attained, and where it has been

What does it mean to experience a book? To a bibliophile such as Alberto Manguel, smell plays an important part. In a talk at the British Library this week, the one-time protege of Jorge Luis Borges and director of the National Library of Argentina said he was particularly partial to age-old Penguin paperbacks, which he enjoyed for their odour of fresh rusk biscuits.

Audience members responded with their own sense impressions. Peter, a pensioner, said he experienced volumes as smelling of salt and pepper that dryness when you open the cupboard with a touching of the sea, while 46 -year-old Donna was recognized that she had recently bought a book for her young son partly because it reeked of the rain.

To curators and historians, smell has always played an important role in assessing the descent and condition of historic volumes, and in working out how to look after them. I have no vocabulary to define this, but there is a curious warm leathery smell to English parchment, unlike the sharper, cooler scent of Italian skins, wrote the Cambridge University don and librarian Christopher de Hamel in his bestselling Meetings with Remarkable Manuscripts.

But that absence of vocabulary could be about to change, thanks to a groundbreaking project by researchers at UCL Institute for Sustainable Heritage, who have devised a style of pertaining such apparently subjective descriptions immediately to the chemical composition of volumes. In a paper published this week in the publication Heritage Science, Cecilia Bembibre and Matija Strli describe how they analysed samples from an age-old book, picked up in a second-hand shop, and developed an historical book odour wheel, which connects identifiable chemicals with people reactions to them.

Using fibers from the fiction, they produced an extract of historic book, which was submitted to 79 visitors to Birmingham Museum and Art Gallery. Chocolate, chocolate or chocolatey were the most frequent terms used to describe the smell of a copy of French novelist Bernard Gassets 1928 fiction Les Chardons du Baragan, followed by coffee, age-old, wood and burnt.

From the analytical perspective, and given that coffee and chocolate “re coming out” fermented/ roasted natural lignin and cellulose-containing product, they share many VOCs( volatile organic compounds) with decomposing paper, wrote the researchers, who mixed research results with those of earlier research projects, such as studies of a 1940 s visitors book at the National Trusts Knole House in Kent. Their survey also took them beyond volumes themselves, to the places in which many of them are read: libraries. In another experimentation, they asked visitors to the Wren Library in St Pauls cathedral to describe what the library reeked like to them. Everyone described its smell as woody, while 86% likewise experienced it as smoky, 71% as earthy and only under half( 41%) reported the scent of vanilla all fragrances associated with particular chemicals in age-old books.

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The smell of heritage researcher Matija Strli with his nose in a book Photo: Supplied

The project originated in Strlis observation of the best interests of smell to curators and librarians. Librarians have told us that its the smell that makes readers first. Its the style libraries transmit, before people even get to the books; but what the books transmit through smell is also interesting. The notion is to propose a large theoretical framework of which reeks hold culture value for us as national societies, he says.

Strli, a professor of heritage science at UCL, is a chemist by training. We know very well how to analyse the chemicals, but what they signify, and the emotions they trigger, is a completely different matter. For that, you need a multi-disciplinary survey, he mentions. It wasnt until the arrival of Bembibre a PhD student with a background in communications that the project began to acquire an anthropological and cultural breadth.

Libraries such as St Pauls, dedicated to historic volumes, smell different to those housing more recent literature, mentions Strli. We know that volumes produced before approximately 1850 have a different smell to those produced between 1850 and 1990, and thats because late 19 th- and most 20 th-century publication was is characterized by acid sizing the process to which pulp was subjected to reduce the water-absorbancy of paper, so that it could then be written on.

The living for individual volumes likewise affects their smell: how far they have travelled; whether they have been kept in damp or dry surroundings. As De Hamel points out, some manuscripts had neither conjured from their original shelves since the working day they were completed; others have zig-zagged across the known world in wooden chests or saddle bags, swaying on the backs of horses or over the oceans in little sailing ships, or as aircraft freight.

The medieval manuscripts De Hamel was dealing with were created by hand on long-lasting parchment made from animal skins which likewise have their own distinctive smell. Industrialised publishing from the mid 19 th-century created less-hardy volumes, prone to a fate that every secondhand book collector dreads: foxing, the brown blotches that appear on so many age-old volumes. Foxing occurs when small impurities left by the metal beaters used to process the paper pulp combination with fungal growing on the ageing paper.

Many people assume the blotches themselves commit age-old volumes their familiar musty pong. In reality, mentions Strli, the smell is due to the release of chemicals such as furfural and hexanol as the paper itself decomposes. Hexanol is often described as smelling farmlike or of old clothing or age-old room, which the odour wheel entrusts to a category labelled earthy/ musty/ mouldy.

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Bembibre analyse the science of book fragrances in the lab. Photo: National Trust/ James Dobson

But foxing itself is likely to be less prevalent as manufacturing changes. In the 1980 s, the technology changed because of environmental concerns about the chlorinated chemicals emitted through the manufacture process. The happy consequence of that was that the paper became more stable again, mentions Strli.

The researchers belief the historic book odour wheel could become a useful diagnostic tool for curators across a wide range of areas, helping them to assess the condition of objects through their olfactory profile. If a book reeks chocolatey, its likely that it is liberating vanillin, benzaldehyde and furfural three chemicals associated with the degradation of the cellulose and lignin in paper. But such studies also has wider implications, as the heritage industry grapples with a new those who are interested in the historical importance of smell. By documenting the words used to describe a heritage smell, our study opens a discussion about developing a vocabulary to identify odor that have culture meaning and significance, mentions Bembibre.

So what can the odour wheel tell us about Manguels description of Penguin volumes as smelling like fresh rusk cookies? Biscuits is a word that often comes up when describing volumes. Two compounds in particular: furfural( smelling of sweetness or bread) and vanillin( smelling of vanilla) could be responsible, mentions Bembibre. His terms might indicate that the books themselves are degenerating, but they likewise reveal his pleasure in them. The endowment industry has long wised up to this. The British Library shop, a few metres from the theater where Manguel was speaking, sells a candle that purports to smell of library.

This is not just about the composition of smell itself, but about human sensibility, Bembibre mentions. By reconstructing the smell and assessing the human reaction to it, we will be able to work out what it is that we want to preserve.

Read more: https :// www.theguardian.com/ volumes/ 2017/ apr/ 07/ the-smell-of-old-books-science-libraries