A book has got smell. A new book smells great. An old book smells even better. – Ray Bradbury
You know the smell. It’s nothing you can buy to use as a perfume, though I’m a bit surprised no one has ever tried, and it is uniquely identifiable to anyone who has ever handled an old book. It’s easy to understand that the smell of a new book is a combination of fresh paper and ink (mostly), but what gives old books their unique, slightly acidic odor?
A team of scientists from major European and UK universities wondered about that and did an extensive study. This is what they came up with:
Using supervised and unsupervised methods of multivariate data analysis, we were able to quantitatively correlate volatile degradation products with properties important for the preservation of historic paper: rosin, lignin and carbonyl group content, degree of polymerization of cellulose, and paper acidity. On the basis of volatile degradic footprinting, we identified degradation markers for rosin and lignin in paper and investigated their effect on degradation.
Uh huh. That was helpful wasn’t it? Well, what they were saying in their own inimitable scientific jargon was that among the old books used for testing, a number of compounds appeared over and over with names that I can’t spell and won’t burden you with. Since books are made of organic materials we can guesstimate that those chemicals relate to things more familiar to us like vanilla, mold and tangy acids.
Books pick up odors from their surrounding environment and might also harbor things like smoke and coffee smells. Perhaps wine and scotch afficionados would be best at sorting out the details.
There was a higher purpose to the research than just having fun around the chem lab however. Apparently, odors can determine age and condition of books and paper documents by using special “sniffing” equipment. That in turn could be enormously helpful to libraries, museums and archives in monitoring the condition of their collections, and ensuring items are stored and maintained properly for maximum preservation.
The next time you are in a library and hear loud sniffing from somewhere, don’t get annoyed. Be patient, it might just be coming from a machine.