Heritage scientist Cecilia Bembibre samples the odor of an 18th-century bible. Credit: National Trust / James Dobson.

Old books have a distinct odor that some people just adore. In fact, depending on when and where the paper was made and printed, books age differently; so much so that trained paper conservators can learn about the history of a book’s printing just by smell alone. With this in mind, researchers at the University College London examined all sorts of smells from old books and libraries to classify their odors. Most people seem to think old books smell like ‘chocolate’, but other descriptors also included ‘coffee’ or ‘dirty socks’.

Heritage of smells

“We don’t know much about the smells of the past,” the authors write in Heritage Science. “Yet, odors play an important role in our daily lives: they affect us emotionally, psychologically and physically, and influence the way we engage with history. Can this lead us to consider certain smells as cultural heritage?”

That might sound like an odd hypothesis, but chemist Matija Strlič and colleagues from UCL rolled with it and headed to a local 18th-century library whose shelves contain some books that are centuries old. They sampled air from various locations in the library then ran the samples through a gas chromatograph and mass spectrometer. These instruments identified the various volatile compounds or odors trapped in the air at St. Paul’s Cathedral, the library in question which is famous for its smell. The head curator even insists any conservation measure must preserve the original odor.

The historic paper odor wheel. Credit:

The researchers later partnered with heritage experts to see how visitors at the Birmingham Museum and Art Gallery were subjectively experiencing the various book odors. As expected, the odors of old book elicited a varied response but some impressions were more common than others. For instance, most participants mentioned old books smell ‘woody’, ‘earthy’ or ‘smoky’. Most participants, about 70 percent, agreed that the smell is ‘pleasant’ while a minority thought it was ‘pungent’.

It was surprising to learn that the most common descriptor of old book smell was ‘chocolate’ and its variations. Worthy mentions included ‘coffee’, ‘burning wood’, ‘fish’ or even ‘dirty sucks’. You be the judge which kinds of people found the odor pleasant.

“Our sense of smell is very close to the memory center in the human brain, and therefore we very often associate memories with certain smells very powerfully and very strongly,” Strlič says. “Very often smell triggers old memories that we otherwise couldn’t trigger. It is one of the reasons smell plays such an important role in how we experience heritage.”

With the help of heritage conservationists, the researchers designed a ‘historic paper odor wheel’, the first in the world, which they hope conservators will use it in their efforts. The odor wheel, for instance, could be used by experts to characterize the odors of vintage books and old libraries more easily.

“By documenting the words used by the visitors to describe a heritage smell, our study opens a discussion about developing a vocabulary to identify aromas that have cultural meaning and significance,” said Cecilia Bembibre, a corresponding author and heritage scientist, in a statement.

She added: “The Historic Book Odour Wheel also has the potential to be used as a diagnostic tool by conservators, informing on the condition of an object, for example its state of decay, through its olfactory profile.”