Why Do Old Books Smell So Good?

Walk into an old library or secondhand
bookstore, you’ll be surrounded by that comforting old book smell. You know the
one: some people describe it as a little musty, with hints of vanilla, or coffee, or
even newly cut grass. Or maybe you prefer the smell of new books, which can seem
crisp and fresh. But what causes books to have such distinctive scents? Well it comes
down to a handful of chemical compounds found in the paper, ink, and bindings of
the book. See, paper is made up of wood pulp, so it has a lot of organic
compounds, which are just chemicals that contain carbon. Specifically paper has a
lot of the polymer cellulose, which is a long chain of the molecule glucose, and
that’s bound together with the help of lignin, another complex organic polymer
found in plant cells, and over time these chemical compounds react to things like
light, heat, and moisture in their surroundings and start breaking down. In
the process they release volatile organic compounds, or VOCs, which easily
vaporize and enter the surrounding air. There are different kinds of these VOCs, and which
ones are released depends on how the manufacturer made the paper and bound
the book. If you detect a hint of almond, you’re probably smelling benzaldehyde,
a ring of carbons connected to another carbon that’s double bonded to an oxygen.
It’s naturally found in almonds which explains the scent. A vanilla like
fragrance is thanks to vanillin, the main compound that gives vanilla its smell and
flavor. If you smell something sweet, it’s likely because of ethylbenzene, a ring of
carbons connected to a short carbon chain that’s often used to manufacture
plastic. It’s also in things like inks and paints. If you’re detecting a light floral
aroma, you’re probably smelling 2-ethyl hexanol, a kind of alcohol
that’s often used in solvents, but also in flavors and scents. New books released
different kinds of VOCs because modern manufacturing processes use different
kinds of chemicals like hydrogen peroxide to bleach the paper and alkyl
ketene dimers to make people a little water resistant. Scientists and
historians can use these volatile organic compounds to learn more about
the age and condition of older books, or to reveal parts of their history like
whether they’ve been exposed to smoke or had water damage. And learning more
about old book smells can help historians determine which ones are
degrading and need to be better preserved and protected. So it turns out
we can learn a lot from the smells in books, not just the words in them. Thanks
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