Every book lover knows that there is nothing, absolutely nothing, that can beat the aroma of a book in this whole wide world. It doesn’t matter if the book is old or new. Books smell great.
Old books tend to smell like vanilla flowers and almonds. This is because of the breakdown of certain chemical compounds in the paper. Similarly, new books smell like they do because of the chemical compounds used in making them.
But why do books smell?
The reason is that books, old and new, give off hundreds of volatile compounds (called VOCs for short). These compounds have different origins. Some are the result degradation, and some originate from the type of paper, binding adhesive and printing ink used in the book’s manufacture.
When it comes to old books, the aroma is a result of the gradual breakdown of cellulose and lignin (complex polymer of aromatic alcohols). Lignin is the same chemical that makes the color of old paper yellow, as it becomes oxidized over an extended period to break down into acids, which in turn break down to cellulose. The paper that is even more delicate contains less lignin than cheaper materials, like the paper used in newspapers. Type of paper and age of the book affects the compounds produced and their concentrations. For instance, ancient books contain more lignin than modern novels.
When it comes to new books, their aroma is highly variable. Three factors determine the smell: the paper itself, the ink used to print it and the adhesives used in the process of bookbinding. Modern binding resins are often based on copolymers. In the papermaking process, the paper is treated with a variety of chemicals, to achieve desired properties. Some of these are odorless, and others react and contribute to release of VOCs. The petrochemicals used as solvents for inks can also be contributors.
In short, no single chemical is responsible for the aroma of books. It’s a result of numerous complex, volatile compounds. Teamwork is everywhere!