Tuesday 11 October 2011

Jansz and some rambling regarding Autolysis

This week I was lucky enough to catch up with Natalie Freyer, the head winemaker for Jansz Tasmania, now Nat has forgotten more than I’m likely to ever learn about Sparkling wines, but manages to wear it all with a delightfully no nonsense Australian down to earthiness.
Nat was over in the UK with some friends on holiday, so the bottle of 2002 late disgorged Jansz was a suitcase smuggle job. The rest of her day had been spent with the 9 year old niece of a friend, so a slight blow out was on the cards.
I’d brought along a little curio of a sparkling Gamay from Beaujolais. Made by Xavier and his sister at ….. My rationale for the choice was that they’re actually trying to do something serious with Sparkling Beaujolais, the bottle lists bottling date and date de degorgement, so you’ll know how long it’s been sur lees. 
Ageing wine sur lees, or leaving the wine on the discarded yeast lees for extended periods of time is a pretty common wine making procedure.
What the winemaker is relying on is the breakdown of the yeast cells after their death. This is known as autolysis, and the subsequent products the autolysate. When there is nothing left to break down the system is referred to as being autolysated.
Contained within the yeast cells, predominantly in the Vacuole, are a set of proteolytic enzymes which set to work as the cell dies. The breakdown of the yeast cell can be broken into two separate areas, the protein cell membrane and proteinaceaous intercellular components, then the carbohydrate cell wall.
Between the breakdown of the membranes and cellular wall there are a host of different compounds produced. Nitrogenous compounds from the protein breakdown work as nutrients for still living yeast cells and are very important in helping malo-lactic bacteria later on. The polysaccharides from the cell wall  end up as B1->3-glucans and mannoproteins. There is some evidence that the mannoproteins are related to the development of extra finesse and persistence of mousse.
The added mouth feel and aromatics that develop with ageing on lees is particularly important with the traditional sparkling wine styles (sekt and prosecco excluded) as they are made from non-aromatic varietals that are often harvested quite unripe (10 to 11 degrees is quite common for their still wines.
Xavier in his Granit Sparkling Gamay is looking to use this as much as possible to flesh out what is by its nature a very angular and difficult wine, there is the obvious shadow of cherry fruit and minerality that defines a good Beaujolais, but the 9 months of on lees ageing has softened this and added an accessibility to the palette. I’m told that their goal is to release everything at 24 months of ageing on lees, but as it’s a new project they’ve been releasing some bottles early.
We followed the Granit with Nat’s top wine, 2002 LD Jansz, the wine had been disgorged (taken off its lees) about 9 months ago, so that’s close to 9 years of ageing and increasing in complexity.
One of the most interesting things about ageing sparkling wines on their lees is that the dead yeast c ells provide a measure of protection from the oxidative ravages of time, meaning that you get a wine that has the added complexity of age, but without some of the slightly obscurative sherried like notes that often would be expected of a similar length of normal bottle ageing. I’m told that in time the freshness fades and the wine rapidly returns to a condition similar that of a bottle aged normally for the same length of time, but I have no personal experience of this.
The Jansz 02 LD was stunning, almost Sauternes like in its richness, with some tropical fruit notes vying with the lush yeastiness and subdued sparkle. Once again I was forced to concede that Nat’s making some truly excellent wines on the Tasmanian hill sides, they’re not Champagnes, but  knowing what she thinks of the bulk of Champenois fruit I’m certain that she’d never want people to make that mistake.

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