She Blinded Me with Science 9/27/14

She Geek Eris drops a knowledge egg on dat ass via her segment on local radio show The Week in Geek. Here are this week's topics:

In Honor of Banned Books Week: The Science Behind Our Love of Books

There are few scents as distinct and beloved as that of an old book. If you're like me, that musty, earthy smell seems to trigger something in your brain that makes you feel at home and comfortable. Nothing else smells quite like the pages of your favorite book, and you can thank chemistry for that.
Specifically, the smell of books can be attributed to volatile organic compounds (VOCs), which are essentially carbon based chemical compounds that can evaporate at room temperature. Books in particular can give off several hundred VOCs, usually associated with their paper, ink, and binding adhesive. Each printing of a book will likely have its own unique smell based on its particular combination of the type of paper used, how the paper was treated, what kind and color of ink was used in its printing, and the adhesive chosen to bind it together. Since there are so many factors and possible combinations of chemicals that can be used to print each book, it's no wonder that they each seem to have their own, distinct smell. 

Espresso Book Machine - small scale, modern printing press.

Older books carry an even more distinct and undeniable scent that seems to evade artificial replication. This is because the final, and possibly most important, factor in how a book smells, is time. As books age, their chemical compounds begin to breakdown and release even more VOCs. The paper, specifically, is a large contributor to their scent over time. Most paper commonly used in book printing is derived from wood chips and contains lignin. Lignin is a complex polymer that helps strengthen the cellular walls in plants and is closely related to vanillin. So, as the lignin in a book's pages begins to breakdown over time, that chemical reaction produces the underlying hint of vanilla present in most aged books. 

16th Century Printing Press at the Museum Plantin-Moretus, in Antwerp

Much like a fine wine, the scent of an old book cannot be traced back to a single source and keeps getting better as it ages.