Come to find out the sweet part of the “old book smell” comes from the molecule, lignin, which is present in all wood-based paper. The structure of lignin (as shown in the image) is closely related to vanillin, the primary component of the extract of the vanilla bean. As it breaks down, lignin releases vanillin, which gives old books that faint vanilla scent.
Lignin is a complex polymer of aromatic alcohols with molecular weights in excess of 10,000 g/mol and is one of the most abundant organic polymers on Earth. Lignin constitutes roughly a quarter to a third of the dry mass of wood.
In fact, commercial vanillin (for vanilla extracts) was synthesized from a lignin containing byproduct produced during the making of wood pulp. Today most vanillin is produced from the petrochemical raw material guaiacol.
© 2015 Steve Farmer
