You know the deal, the more some folks learn about a topic, the more shortcuts/slang/acronyms/initials/technical jargon can be tossed around. I’m here to help you understand those sometimes mysterious words and phrases, thus – Wine Words Demystified!
The decomposition of spent yeast cells by enzymes they contain. When a wine is SUR LIE, or on the LEES, it is left in contact with the spent yeast cells that performed FERMENTATION. As the yeast cells break down, the impart, for reasons not fully understood, an extra dimension of flavor, VISCOSITY, and complexity to the wine
In other words, yeast cells which may be present on the grapes naturally or introduced by the winemaker, consumes the sugars in fermenting crushed grapes and converts it to alcohol and carbon dioxide (CO2). When the alcohol reaches a certain level it kills the yeast. After the yeasts die they begin to decompose. The dead yeast cells are referred to as lees. If a wine is left in contact with lees as they decompose, and add aromas, flavors and complexity to the wine. Depending on the wine, this may be desirable (in the case of Champagne, some Chardonnay, and other white wines) or undesirable.
While the decomposition of dead yeast cells doesn’t sound appealing, if you’ve ever enjoyed Champagne, or other sparkling wines made in the traditional method you can’t argue with the results!