My partner Julia owns a 1965 paperback edition of Hemmingway’s A Moveable Feast. It lives on our bookshelf in a special section, asleep atop Dickens, Faulkner, and Allan Sichel’s The Penguin Book of Wines. It is creased and cracked, the back hangs on by a quarter-inch of yellowing paper, and a dog’s ear adorns the cover (yes, the cover). Not eighteen inches away lies the 2004 edition of de Tocqueville’s Democracy in America, also published by Bantam, also horizontal, also a mass-market paperback.
Each book smells like a different world.
A Moveable Feast: overpowering. Musty and sweet, like fruits just barely starting to rot. Hints of ocean, sand, salty air, and long-ago-charred forest. One deep breath and I’m fifteen again, sunk into century-old furniture in my grandmother’s apartment, nose in P. G. Wodehouse’s Right Ho, Jeeves, reading by candlelight during one of Beirut’s many power outages.
Democracy in America: subtle, elusive. Week-old sawdust, but the smell fades just as you start to place it. Put the book down, wait a few minutes, try again. Maybe… wet ash? Summer rain?
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When you bury your nose in a book, you’re smelling the products of a chemical transformation: the transformation of solid paper into a gas—or, rather, multiple gases. Some might say it’s ironic that smells we love so much tell the tale of a book’s slow-motion self-destruction. Others—myself included—think it necessary and proper that the disintegration of beautiful words should produce enchanting smells.
The transformation starts with the solid chemicals that make up paper, the most abundant of which is cellulose. Cellulose is a polymer: a gigantic molecule made from repeating subunits (in this case, the sugar glucose). Many polymers dissolve in water, but cellulose does not. Plants take advantage of this, building cell walls based on cellulose from the sugar they photosynthesize. In addition to helping keep water in, cellulose helps plant cells maintain a rigid structure. Both of these traits are useful for paper. Cellulose can be pulped, shaped, and colored. It can be chemically treated to absorb just the right amount of ink without bleeding. (Confusingly, this is called “sizing” and has nothing to do with cutting the paper down to size.)
In the 15th century, cellulose was derived from cotton or linen and sized with animal gelatin. Paper made this way is durable, but expensive. The next few hundred years brought innovations that made paper cheaper and mass-produceable, but at the expense of durability. In the early 19th century, paper began to be sized with alum-precipitated rosin, which rendered it acidic. Many chemical reactions are acid-catalyzed, meaning they occur faster in acids than they do in plain water; the chemical breakdown of cellulose is one such reaction. When parts of a book start turning into gas, that seriously impacts the structural integrity of the book. Disintegrating, yellowing, and browning pages—as well as enchanting smells—are the hallmarks of old books printed on acid paper.
Non-acid paper degrades too, though more slowly. And book smells don’t all come from cellulose degradation: though it’s the main constituent, there are others, and those also decompose into a library of chemicals. Aldehydes and ketones can smell fruity, grassy, or like almonds, caramel, cookies, or chocolate; vanillin can smell like its namesake bean; short-chain fatty acids are responsible for some of the funkier odors of decay and decomposition. Toluene and xylene smell sweet. These chemicals and others can occur in an uncountable number of mixtures, depending on what the paper was made from, how it was produced, how it was stored, and how much it was touched (or wasn’t).
Like everything else these days, you can order the smell online; it’s available in perfumes and candles. But I recommend the old-fashioned approach… spend a few bucks and buy a used mass-market paperback. Not only will you get the comforting scent of childhood memories, you’ll get a few choice words, too.
Featured image: @jamesc.lark via Twenty20