Everyone is familiar with the scent of old books, but few know where that smell comes from—or why some people become so captivated by it that they find themselves “glued” to libraries or second-hand bookstores. As the saying goes, the older the treasure, the more valuable it becomes. Books, often described as the repositories of human civilization, are no exception.
Volumes that have been preserved for decades or centuries not only carry immense intellectual worth, but also a kind of historical weight that defies quantification. And if you’re someone who frequents libraries or archive rooms, you’ve likely noticed that old books carry a distinct aroma. According to Matija Strlic, a scholar at University College London, the smell is “a combination of mustiness, vanilla, almonds… plus a few acids thrown in.” It may sound unpleasant, but it’s strangely addictive—almost like part of the book’s very identity.
So where does that smell come from? The secret lies in volatile organic compounds (VOCs)—hundreds of them—embedded in the paper, ink, and binding glue. Over time, these VOCs break down and release a mix of chemicals that form the iconic scent of old books.
In fact, every book smells slightly different depending on the type and quantity of VOCs used during production. A printing company survey once linked almond-like smells to benzaldehyde, sweet scents to toluene or ethyl benzene, and floral tones to 2-ethyl hexanol.
New books don’t smell the same, partly because their materials are less degraded, and partly due to the fact that paper quality has declined over the past century. Most modern books are made using cheaper, wood-based paper that doesn’t preserve aromatic compounds well.
Depending on when a book was printed, additional chemicals may have been added—chemicals that can even help date a book when other indicators are missing. For instance, high concentrations of furfural are often associated with books published before the 1800s. This finding was confirmed in studies published in ACS Sensors, Analytical Chemistry, and Heritage Science.
In some cases, that scent also reflects external influences—smoke, mold, or even dried flowers pressed between the pages. But beyond nostalgia, this aroma serves a very real and practical purpose.
It turns out that seasoned librarians can “smell” which books are in danger. It’s a skill developed over years of handling rare and fragile volumes. Books emitting certain decaying VOCs must be prioritized for restoration or digital replication. A 2009 study in Analytical Chemistry identified around 15 key VOCs that degrade faster than others, signaling early deterioration.
Books decay—this is a fact of life. Humans have been making books for over 4,500 years, beginning with scrolls and evolving through hand-bound volumes to today’s digital formats. According to Dr. Karl Kruszelnicki, a science commentator from Australia, old books smell the way they do because the chemicals in their paper, ink, and adhesives transform over time and emit gases.
He explained, “Old books smell a little sour, sometimes moldy. People have described their scents as chocolate-like, burnt, musty—even like smelly socks. During manufacturing, various chemicals were introduced to the paper and many never fully broke down. Their odor depends on the type of paper, the chemicals used, and the era in which the book was made.”
That’s why a glossy hardback used for reading over coffee smells completely different from a cheap mass-market paperback.
The time in which a book was published—and the production method used—greatly affects its lifespan. Dr. Karl added, “You could read a 150-year-old book or even one from 1,000 years ago. But books printed in the early 20th century? Many of them are unreadable today because they were made with low-cost, acid-filled paper to keep prices down. That acidity has caused them to break down rapidly over time.”
But why does the smell of old books evoke so much emotion?
For many, the scent of an old book floods them with memories, nostalgia, and comfort. Dr. Karl attributes this to a fundamental biological reflex: the sense of smell bypasses the front brain and goes directly to the limbic system, the seat of memory and emotion. All living beings, down to bacteria, have chemoreception—and in humans, scent can trigger memories more vividly than any other sense.
One whiff of an old book might conjure your mother’s perfume, a childhood trip in a family car, or hours spent buried in a novel under the covers.
Even if it’s your first time holding a specific book, its smell might involuntarily trigger emotions from past experiences, or remind you of completely unrelated things—from lost eras, forgotten places, or people you once knew. And that, in itself, is a kind of magic.
