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Why Do Old Books Smell? Matija Strlic, professor UCL Centre for Sustainable Heritage,  gave a great lunch hour lecture at the British Museum on June 21, 2012. A Book by any other name would smell as sweet concerned the importance of smell to heritage scientists, archivists, museum staff, and conservators, focusing specifically on the connection between measuring specific odors and the degradation rates of paper.

He began by showing a Dr. Who clip, when the time traveller, despite being in the 51st century, deeply inhales and relishes the aromas of a library. Strlic noted that “we’ve all enjoyed the smell of a library,” and cited an anecdote that while commissioned for St. Paul’s Library, he was asked to please preserve the smell during a restoration project. Why would a library like to smell like old books?

M. Lindstrom Brand Sense (2005) (cited by Strlic) noted that after sight, smell was the most important sense for consumers (although over 80% of advertising is still ocularcentric):

  • 58% sight
  • 45% smell
  • 41% hearing
  • 31% taste
  • 25% touch

That is, a library should and must smell like books, because our happy memories of going to the library as a child are olfactive memories.  Strlic points out that odor memory is so primal, located so deeply within the rain that it is intricately and intimately connected to memory. Our “odor memory” remains 64% accurate after one year.

The sense of smell is intimately linked to memory and emotion, but as my sister claimed (via Facebook chat) when I told her I was attending this talk, “I have a horrible sense of smell; they say that it’s the next thing to go since we don’t need it anymore…” This is a common misperception perpetuated by Freud (amongst many others) in Civilization and Its Discontents that when man stood upright, he became a visual creature and his sense of smell diminished. A lot of my research is an attempt to reclaim the importance of the lower sensorium (aesthetically, culturally, etc.), and Strlic’s talk demonstrated that even for the scientist, the lower senses can be just as, if not, more useful than sight.

Strlic passed around three sealed jars (one to each row of the audience), each containing a scent, which he “scientifically” created by baking the object in an oven for two hours and then capturing the scent in a jar. The three jars contained the aromas of either 1. Old wood-paper book, 2. Old newspaper, or 3. Old Barbie doll. Most of us were able to properly identify the smell of our jar. The old newspaper smelled harsh and acidic, vinegarish. The Barbies obviously smelled of plastic. My jar smelled distinctly woodsy and vanilla-like, that is, the smell of an old book.

So what is it that makes old books smell like, well, old books? Because one of the major two components of paper, lignin, releases a vanilla scent during degradation. (The other major component is cellulose, more on that below).

In Perfumes: the Guide, the smell is compared to high quality vanilla absolute.

‘Lignin, the stuff that prevents all trees from adopting the weeping habit, is a polymer made up of units that are closely related to vanillin. When made into paper and stored for years, it breaks down and smells good. Which is how divine providence has arranged for secondhand bookstores to smell like good quality vanilla absolute, subliminally stoking a hunger for knowledge in all of us.’

– From Luca Turin and Tania Sanchez’s Perfumes: The Guide (cited in Strlic’s talk)

Strlic didn’t discuss the smells of and degradation rates of older writing materials—papyrus, vellum, even linen—nor did he spend any time discussing binding materials and book covers. That wasn’t his concern.  Anyone who has worked in older archives already knows this from handling old books, that linen-based paper is pretty hardy (minding occasional wormholes) and doesn’t discolor too badly. The linen rags used to create this type of paper had long binding fibers, resulting in high quality and long-lasting paper.

During the 18th and 19th century, however, the demand for paper increased, leading to the movement toward wood pulp based paper. The wood paper, consisting mostly of cellulose (shorter binding fibers) needs to be bound with rosin, and alum, which is quite acidic. The combination of shorter, less stable fibers and high acidity leads to a quicker degradation state for wood-based, or cellulose, papers versus linen. (Here, you can think about all the musty and yellowed paperbacks you can find at yard sales & secondhand book stores, in comparison to the relatively unchanged Renaissance materials). Most paper from the mid-18th century through the 1990s* was made from the degradable, acidic, aromatic, wood pulp papers. This was the paper that Strlic is worried about as a conservationist and wishing to learn more about its degradation/aromatic connection.

Basically, the jar experiment was a very low-fi version of “headspace analysis,” the extraction of surrounding molecules of a rare book to measure the traces of volatile compounds. Basically, the more volatiles=more aromatic, and “the more intense the smell, the less stable the paper.” Not only does the intensity of smell matter, but the taxonomy does as well. Lignin is a complex compound and as it degrades it releases different aromas depending on which aspects are breaking down most quickly.

Old book smells are commonly compared to vinegar or rotten fruit, in addition to vanilla.  As lignin, a complex chemical compound, breaks down you can tell by the smell which component is breaking down most quickly.  It degrades into vanillin (obviously the source of the lovely vanilla odor), acetic acid (vinegar scent), short-chain aldehydes (dry grass, hay smells) and/or benzaldehyde (which releases a bitter almond aroma). Or as Strlic, noted, all together, not unlike “vanilla ice cream with toffee nut topping”!

The lovely vanilla smell, however, means that the lignin’s decomposition has made it photosensitive, exactly the sort of thing conservators and exhibitors need to know before causing irreversible damage.

Strlic’s talk was informative and entertaining. He even passed around a Kindle with an attached “book smell” Little Tree air freshener. As someone who thinks about smell and old books in the archives a lot, but not always in connection to the scientific significance of their odor, I found his talk both fascinating and useful for my research.

* Starting in the 1970s, the recognition of the environmentally unsound paper-producing process led to developments to create greener paper sources. From that time, but especially in the 1990s when papers’ components were altered to contain less acidic (alum-based) materials and instead 20% calcium carbonate, leading to paper that is almost neutral, but leaning toward alkaline.

Related viewing: Why we love the smell of old books