In our Ask the Sommelier series, we put your wine-related questions to top sommeliers. In this instalment, IWSC judge and head sommelier at London’s Mark’s Club Elvis Ziakos explains lees: what they are, and the part they play in wine.
‘I’ve been increasingly interested in quality sparkling wine, and I’ve noticed lots of bottles state how long the wine has been “aged on lees”. I know these wines have spent some time ageing, but I’m not sure what “on lees” means, and whether it’s something specific to sparkling wine?’
John from Edinburgh, Scotland
SOMMELIER ELVIS ZIAKOS RESPONDS:
What are lees in wine?
‘Essentially, lees are dead yeast cells left over after fermentation. In liquid fermentation (the process that makes wine), active yeast is added to grape juice, which converts sugar into alcohol and carbon dioxide. Once the yeast has finished its lifecycle and consumed all of the sugar, it settles on the bottom of the vessel used to make the wine, along with the skins from crushing the grapes. This mixture is coarse in texture and is what’s known as the ‘gross lees’, which is usually removed immediately from the wine.
‘There’s another type of lees called “fine lees”, which is the dead yeast left from fermentation that does not immediately settle at the bottom of the vessel and has a silkier texture. This can aid the winemaking and wine ageing process.’
What do lees do?
‘One of the main reasons for ageing a wine on the lees is to enhance the flavour, texture and mouthfeel of the wine. This happens due to a process called “autolysis”, where the yeast releases amino acids and small amounts of sugars as it breaks down. This leads to enhanced flavour and texture sensed on the palate when drinking the wine. White wine is more commonly aged “on lees” than red wine in order to improve structure and texture – it’s a less popular technique with red wine due to the structure already present from tannin.’
Can you taste lees in wine?
‘Fine lees are naturally odourless and tasteless, but in reaction with the wine through ageing they create round, creamy flavours. They are mostly associated with sparkling wine due to the fact that traditional method sparkling wine goes through a second fermentation in the bottle to create the fizz. The fine lees therefore spend more time in contact with the wine, giving vintage cuvée Champagne in particular its signature creamy, brioche-like flavour and nutty aroma. Muscadet wines from the Loire Valley in France are also well-known for being aged “on lees” and are recognised for their complexity and creaminess.’
What does aged ‘on lees’ mean when it comes to Champagne?
‘Usually, it is at the discretion of the winemaker how long they age wine “on lees” for. It can be as little as a few months, and as long as 10-20 years. The phrase “aged on lees” (or sur lie in French) might be more commonly associated with Champagne. This is because, for a wine to be a Champagne it needs to have been aged for 12 months “on lees”.
‘The wine and lees will have been reacting in the bottle for that amount of time prior to disgorgement, creating the rich flavours associated with the drink. For vintage cuvées, time on lees is a minimum of 36 months. A great example of a Champagne aged “on lees” is Dom Pérignon Plentitude 2, which has the complexity of flavour that comes with being aged on lees.’
Interview by Louella Berryman
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