- The act of stirring the lees in vat or barrel. Helps avoid production of hydrogen sulphide and facilitates absorption of wood tannins and lees flavours
Once fermentation has pretty much finished, stirring takes on a different mission. The majority of wines are racked into clean vessels and left alone to mature in peace. Some purists even insist that disturbing the wine during this stage can bruise it (whatever that means). If a wine is undergoing malolactic fermentation, which is frequently done with red wines and with chardonnay, then stirring the lees will help foster the malolactic bacteria and bring out the desired soft ‘sur lie’ quality.
Lees are dead yeast cells, and mixing them into the wine helps integrate toasty and biscuity qualities into the wine. You’ll find this character in sur lie chardonnay, vinho verde, and quality sparkling wines, especially champagne. Sometimes the wine is bottled directly from the barrel, in which case the label may say “Bottled on lees”or “Unfiltered” and the wine may show a trace of fine sediment. The resulting wines generally show more character than those that have not undergone lee stirring.