What Do Old Books Smell Of?

Our sense of smell can have a strange effect on us. One whiff of pineapple can send you rushing back to your tropical holiday, while the tang of vinegar on chips can make your mouth water.

The smell of old books is particularly distinct – one step into a second hand book shop and you know where you are, even if you are blindfolded. If you have ever wondered why books have this wonderful smell, now is the time to find out. A team of scientists, led by Dr. Matija Strlic, a chemist at University College London, have analysed the smell of old books into its component parts. Within the post, we'll be taking a look at the results. You can read about this study in depth at: Material Degradomics: On the Smell of Old Books.

Going organic

The reason that these smells are present is all down to the fact that books are composed of organic materials. For example, the paper pages could be derived from cotton or wood pulp and the glue used in the old fashioned binding may be made from animal skins or from milk protein. Over time, these organic compounds are broken down into several hundred volatile and semi-volatile organic compounds (or VOCs), which are released into the air. So, when we are in a library breathing in the air, these VOCs travel up our nose and are detected as that familiar and comforting smell we associate with old books.

Divide and conquer

In the study, a small amount of paper was taken from 72 well-characterised 19th to 20th century historic papers in total, each chosen based on their variability. To analyse and identify the VOCs of complex materials like paper, ink and adhesives takes serious scientific knowledge and skill. It also requires several pieces of specialist equipment. Headspace sampling coupled to GC-MS were used after a 24 hours pre-degradation procedure, as this was particularly appropriate for the non-destructive, non-evasive method needed. From the resulting graph, known as a chromatogram, the team were able to identify the types of VOCs present and also quantify the amount of each. 

So, what exactly did Dr. Matija and her team conclude from this analysis? Apparently, the smell of old books is, “A combination of grassy notes with a tang of acids and a hint of vanilla over an underlying mustiness.” Nice! 15 compounds were detected repeatedly in the study, and are therefore considered to be consistent indicators for a book’s deterioration. 

Is paper degradation analysis useful?

The study of the degradation of old books helps the preservation of important historic documents. This means that future generations can enjoy the simple pleasure of taking an old book from a shelf and browsing through its contents, all whilst taking in the unmistakable and evocative smell that emanates from its binding and pages. Life would just not be the same without the smell of old books. 

If you would like to learn more about headspace GC, read this article: Headspace Gas Chromatography as a Green Analytical Technique.

Image Source: Old Books