Prior to the 19th century little was known about the process of fermentation or the
causes of spoilage. The Greeks stored wine in earthenware amphorae, and the Romans
somewhat extended the life of their wines with improved oaken cooperage, but both
civilizations probably drank almost all of their wines within a year of vintage and
disguised spoilage by adding such flavourers as honey, herbs, cheese, and salt water.
Wooden barrels remained the principal aging vessels until the 17th century, when mass
production of glass bottles and the invention of the cork stopper allowed wines to be aged
for years in bottles.
In the mid-19th century the French chemist Louis Pasteur and others explained the
nature of fermentation and identified the yeasts responsible for it. Pasteur also
identified the bacteria that spoil wine and devised a heating method (later called
pasteurization) to kill the bacteria. Later in the century, methods were developed for
growing pure strains of specific yeasts in culture. Advances in plant physiology and plant
pathology also led to better vine training and less mildew damage to grapes.
Mechanized innovations in the 20th century have mainly contributed to quality control.
Stainless steel fermentation and storage tanks are easily cleaned and can be refrigerated
to precise temperatures. Automated, enclosed racking and filtration systems reduce contact
with bacteria in the air. Beginning in the 1960s, the use of mechanical grape harvesters
and field crushers allowed quick harvesting and immediate transfer to fermentation tanks.