March 14, 2011

Sedimentary Journey

Lees *
    Grape solids and dead yeast cells that have precipitated to the bottom of the tank or barrel during ageing. Can contribute to complexity, and facilitates malolactic fermentation.
During the first few days of fermentation, the new wine will throw off quite a bit of grape material as well as spent yeast cells – the gross lees. After racking, the wine will contain very few grape solids, and the fermentation will then produce mainly yeast cells. Lees contact is an important component to the wine’s character and in some cases is absolutely essential. For example, a ‘sur lie’ chardonnay may have spent months in the barrel, with the cellar master frequently stirring the lees into the wine (see Battonage, Jan 10/11). This gives the wine a unique biscuity character that only comes about through careful ageing on the lees. Champagne also gets much of its character from lees. The wine ferments in a closed bottle for months and perhaps years in close contact with the lees. If a wine has a creamy, yeasty or toasty character, it’s likely attributable to the lees.

Properly managed, lees add unique and desirable character, but if the winemaker is not careful, the yeast cells can begin to deteriorate, a condition called autolysis. An autolytic wine can show a number of undesirable odours including ‘beery’, ‘bready’, hydrogen sulphide, and a group of nasties called mercaptans.

You may come across a bottle that says ‘bottled on lees’. This means that the wine was transferred   directly from the barrel to the bottle, without filtering. The wine may even show a trace of cloudiness, which in this case is a bonus.

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