Have you ever wandered into an old library or dusty bookshop and paused to breathe in that familiar vanilla-coffee-grassy scent wafting off the aged tomes? That nostalgic olfactory experience is thanks to a bouquet of chemical compounds.

Modern books smell different because of changes in manufacturing, while old books release distinctive volatile organic compounds (VOCs) as they slowly decay. Scientists are sniffing out these VOCs to reveal secrets about a book’s age, condition, and history.

The Chemistry of Paper

Paper is made of cellulose fibers bound by lignin, while inks and bindings add other organic compounds. Cellulose is a polymer made of long glucose chains, while lignin is a complex polymer found in plant cells.

Over time, light, heat, and moisture cause the paper and compounds to break down, releasing VOCs that vaporize into the air. The manufacturing process also affects the VOCs released as the book ages.

Telltale Scents

An almond scent comes from benzaldehyde in the paper. Vanillin, the main compound in vanilla, is responsible for a sweet vanilla fragrance. Ethylbenzene, used in inks and paints, has a sweet plastic smell. 2-Ethyl hexanol, found in solvents and scents, smells lightly floral.

New books use modern chemicals like hydrogen peroxide and alkyl ketene dimers, so they give off different VOCs. The VOCs can also indicate exposure to smoke, water damage, or other aging factors.

Reading the Chemical Clues

Scientists can analyze the VOCs from an old book to determine its age and condition. The mix of compounds can reveal if a book came from an