Old books, new books, passed down books, textbooks, thick books, thin books—they all have a pretty distinct smell, and there's actually a ton of science involved in explaining why.
Andy Brunning, a Cambridge chemistry teacher, studied the chemical makeup of both old and new books and revealed his fascinating findings on his website, Compound Interest.
Basically, his research says that all books are made from a large variety of different papers, binding adhesives, and printing inks, depending on the manufacturer, which causes them to give off a unique combination of compounds. These combinations give the book its own interesting and unique smell.
Overall, there isn't a ton of research around the smell of new books, Andy said. But there is a lot research around the aroma of old books because this science can help access the condition and age of old books.
In regards to new books, certain compounds like hydrogen peroxide, which is a bleaching agent, and alkyl ketene dimer, which makes the book water resistant, contribute to a book's unusual smell. That and the fact that a large amount of paper is made from wood pulp, which explains why new books can smell like you just stepped inside the Home Depot.
For old books, other compounds found mostly in the paper, like toluene which has a sweet odor, vanillin, which smells like vanilla, and benzaldehyde, which smells almond-like, are created over time as the book deteriorates.
And you know how old books tend to be a yellow-ish color? That's explained by the presence of lignin, a chemical used in the paper of many books made more than 100 years ago. Over time, the chemical breaks down the paper and causes the color to change.
So there you have it—new books smell mostly like the woodsy pulp they're made from, and old books smell like all the chemicals they emit as they age. But the big takeaway is clear: books contain a lot of chemicals, so we should probably stop sticking our noses in the pages to smell them.
