Friday Weird Science: The good old book smell

Jan 04 2013 Published by under Friday Weird Science, Uncategorized

If you're the kind of nerd like me, then you're the kind of nerd that really liked spending time in libraries and old bookrooms as a kid. To this day I love having books around me, especially the old kind with nice leather covers. And of course, if you're spent time around old books, you know that old book smell. It's kind of musty, but evokes happy memories of wood and leather and soft lamp glows, and maybe a nice fireplace (if you're very lucky) by which to sit and dig through intellectual treasures.

And what with all the memories, you start to really love that old book smell. But do you love it so much you could wear it? Pascale at Whizbang alerted me to the fact that there is a "Paper Passion" perfume!

Couldn't make this stuff up. Pascale notes that it might be good to spritz on your e-reader for the authentic paper experience. I do love me some dead tree smell but not quite enough to wear it.

But it made me wonder: does the perfume really smell like old books, and what makes that old book smell? Luckily, Marc Abrahams came to the rescue with a paper that's perfect! And so I present today's Friday Weird Science:

Strlic et al. "Material Degradomics: On the Smell of Old Books" Annals of Chemistry, 2009*

You can tell the authors enjoy themselves some old books. The fondly describe the smell as :

A combination of grassy notes with a tang of acids and a hint of vanilla over an underlying mustiness, this unmistakable smell is as much part of the book as its contents.

I just had to grab a book and take a whiff to confirm, but I think they're right! But what is it from exactly?

And why would people even want to know? It's actually more important than just a musty smelling perfume. Knowing what volatile organic compounds (that will make the smell) are involved and in what stages could allow curators of museums and archivists to tell how degraded old manuscripts are, figure out what part is degrading (the paper itself or the binding), and give clues how to best preserve them.

And of course, you can't just take a chunk of, say, the Doomsday book and send it off to be destroyed for analysis. Some books may just be old by our current standards, but the ones we need to worry about? Those are precious. No books must be sacrificed in the making of this science.

So in order to figure out what is going on with aging books, the authors here describe the development of their own kind of -omics (please, not anther kind of -omics). While studies in living animals use "metabolomics", the study of all metabolics in the body, the authors here propose a "degradome", for dead objects, using a variety of methods to create a fingerprint for the decomposing item. Obviously, they are focused on books, but I have to wonder what will be next. Wood, maybe, but I have high hopes for a degradomics of roadkill.

Anyway, they took a large number of well characterized and known historical documents from the 19th and 20th centuries, and using "headspace" analysis (the analysis of the air immediately around the object) looked at the volatile organic compounds released to get an idea of what was degrading with gas chromatography. They found a few known degradation compounds, such as furfural (part of the sweet smell) and acetic acid (part of the sour smell), and also characterized things like rosin (a solid form of resin from pines that most people think of in the context of cello and violin strings or ballet shoes), and lignin (part of the cell wall of plants), and of course how much the cellulose had degraded (the primary ingredient in paper).

The authors were able to correlate a lot of the products. For example, rosin concentrations correlated with cellulose degradation and with higher acidity. They were also able to classify degradation to different components, with one component mostly acetic acid and the second compounds that are associated with rosin.

Keep in mind, though, not all paper is created equal. Especially historical paper, which wasn't always made of dead trees. Some was made from rags, some ground or pulped wood, and some on other substances entirely (such as vellum or parchment, both of which are in fact made from hide). All of these will give off different profiles of volatile compounds, and will probably need to be analyzed separately.

But the results of this study might help create a profile for paper degradation, allowing curators to identify how badly musty their papers have become, and what might be done to save them. And of course, it also gives rise to Paper Passion perfume.

Strlič, M., Thomas, J., Trafela, T., Cséfalvayová, L., Kralj Cigić, I., Kolar, J., & Cassar, M. (2009). Material Degradomics: On the Smell of Old Books Analytical Chemistry, 81 (20), 8617-8622 DOI: 10.1021/ac9016049

*Amusing side note: Annals of Chemistry is abbreviated Anal. Chem. This always makes me giggle. I'm 12.

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