The next stage in the work of Pasteur was the discovery that certain substances, such as glycerine, are products of fermentation.
"Notable Events of the Nineteenth Century" by Various
In the fermentation process for making alcoholic liquors a little glycerin is produced as a by-product.
"Creative Chemistry" by Edwin E. Slosson
Glycerine retards fermentation and decomposition to a remarkable degree.
"Practical Taxidermy" by Montagu Browne