Process
During fermentation, yeast cells convert the sugar in the grape must into ethanol. When the sugar food source for the yeast and necessary nutrients such as nitrogen run out, or the alcohol level of the wine reaches such a point to where it is toxic for the yeast, the cells die and sink to the bottom of the fermentation vessel. These dead cells, or "lees", are normally removed by racking the wine into a clean vessel. If the wine is left in contact with the lees, enzymes start to break the cells down producing mannoproteins (mannose-containing glycoproteins) and polysaccharides that are released into the wine. In sparkling wine production, a wine is made "sparkling" or "bubbly" because a secondary fermentation is introduced when the wine is contained within a sealed wine bottle. During this time the wine is deliberately kept in contact with its lees inside the bottle for a period ranging from a couple months to several years. Studies have shown that the chemical reaction of autolysis, and its impact on the wine, starts to become noticeable after 18 months and will continue to impart traits for at least 5 years. The sparkling wine is eventually separated from its lees through a technique known as riddling and disgorgement.
Read more about this topic: Autolysis (wine)
Famous quotes containing the word process:
“A process of genocide is being carried out before the eyes of the world.”
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