Vineyard Year – Fermentation

March 19th, 2018

In the tank hall split-level stainless steel tanks, each with automatic temperature-control, allow optimum juice fractioning, settling, fermentation and malolactic processes to be carried out with total precision. Great care is taken to maintain quality at every stage of production. On arrival in the wine cellar, the must rests for between 8 and 15 hours in order to ensure all foreign materials in suspension can settle, after which samples are taken for analytical control. As fermentation progresses in temperature controlled, stainless steel vats, so interventions by the wine maker begins, to ensure the best possible fermentation results and to produce a wine with the desired alcohol content of between 10.5° and 11.5°. If, the wine alcohol level is too low, the wine maker will undertake a process known as chaptalisation, adding small quantities of sugar to the wine, though this is sometimes unnecessary during exceptionally sunny years like 2009, when the grape can reach full maturity without the need for intervention. The natural acidity in the grape juice must also be preserved or even increased to allow successful ageing.

It’s at this point, that the growing skills used to great effect previously in the vineyard, are replaced by the need for an understanding of chemistry if success is to be achieved in the winery. Fermentation takes place in two distinct phases, Alcoholic during the first five or six days, which takes the form of effervescent grape juice, giving an impression that the must is boiling. Thereafter Malolactic fermentation takes place, a biological process, which greatly reduces the acidity of the wine by transforming, through bacterial means, the malic acid of the wine into lactic acid, emitting carbon dioxide in the process. Natural yeast is added to the vats of must, to aid and control fermentation, in a process known as ‘yeasting’. Malolactic fermentation is less intense and less visible, but lasts much longer than alcoholic fermentation phase, requiring from four to six weeks to complete. Acidity diminishes and the wine gains suppleness, refined aromas and a great future stability. Once these fermentations have taken place, the wine is progressively chilled to 10 or 12° C and at this point needs to be clarified to remove the deposit of lees.

Throughout the process, the wine is continually being assessed through regular tasting and systematic laboratory analysis though minimum intervention in the winemaking process is a watchword so that each wine can develop it’s own natural characteristics that arise from the particular terroir at English Oak Vineyard. The wine is now exposed to air for 48 hours to check that it neither oxidises nor browns, followed by an initial tasting and finally a first racking then takes place in November-December in order to separate the new wine from the fermentation lees. It must then be clarified through a process known as ‘fining’. In the end we obtain a still, non-sparkling wine of quality. It is effectively from this moment onwards that the specific tasks associated with the production of Sparkling Wine can begin. The skill of the wine maker now combines with the individual characteristics of the three grape-varieties used to produce Sparkling Wine, Chardonnay, Pinot Noir and Meunier through a delicate process of blending. All play their part to produce the distinctive characteristics that define our various brands. Finally, a process of cold stabilisation occurs, in which the temperature of the wine is lowered to its freezing point, for six to eight days, at the end of which the wine is perfectly limpid and stable and is known as ‘vin clair’ (clear wine). A new racking occurs and the wine rests in the cellar at 10° C. until spring as we move into a new year of growth back in the vineyard. In the winery, fermentation has changed our original sugary grape juice into wine, which now awaits its second natural fermentation cycle. within the Champagne bottle.

 

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