The wine making process
Pressing
The grapes are delivered by trailer to the winery, where they are pumped into press. The press will take up to 2.5 hours to press each load, depending on the variety and ripeness of grapes. The press is programmed to control the duration of pressing, the pressure and the number of times the press turns. After pressing the pips and skin which remain are spread on the vineyard.
The pressed juice (known as must) is pumped into a tank and left overnight to allow any sediment to settle at the bottom of the tank. The clear juice is pumped from the racking valve into the fermentation tank. The sediment is filtered away using a pressure filter to ensure that any unwanted particles are removed.
Once in the fermentation tank, the sugar and acidity levels of the juice are analysed and the juice enriched if necessary (in line with regulations). At this point the selected yeast culture is added and the fermentation starts.
Fermentation
White wine production
Fermentation is the conversion of sugar to alcohol, causing a rise in the temperature and the emission of carbon dioxide. The tanks are temperature controlled by cold water pumped through the cooling jacket that surrounds the tank, maintaining a temperature of 17 - 18C degrees centigrade. This ensures that there is no loss of alcohol or flavour. The fermentation lasts 10 to 14 days. Throughout this period the tanks are filled to 90%, allowing the wine to bubble.
Red wine production
Red wine at Denbies is made from Dornfelder and Pinot Noir. The grapes are crushed, and pumped into open fermenting bins, and are allowed to ferment at temperatures of 25 to 30 degree celsius. This enables the extraction of colour and flavours from the skins into the wine, facilitated by warmer temperatures, and the presence of alcohol. To maximise extraction, the floating grape skins are pushed below the surface on a regular basis. Once fermentation is complete (after about 2 weeks) the wine is drained off and the skins are pressed.
Racking
After fermentation the wine is pumped from the racking valve into another tank. The sediment is again filtered off and is spread over the vineyard. Protein is then removed by adding a small quantity of bentonite, reducing the cloudiness. Sulphur dioxide is also added to protect the wine from oxidation. Gelatine and Kieselsol are then added to settle the wine and remove tannin. After racking the tanks are kept full. Only after the second racking is the wine filtered and blended.
Blending and Bottling
Wine can be blended or bottled as a varietal. After blending, the wine is filtered for a second time, and then bottled. After filtration, some wines are left to mature in oak barrels, resulting in a rounder and fuller oaky taste. Both French and English oak are used for Denbies wine.
Once bottled, the wines are laid down in crates to allow a period of maturation. Some varieties have to mature in the bottle for several months before they can be brought up from the cellars to be labelled and sold.
Most of the wine produced at Denbies Wine Estate may keep for 1 to 5 years, depending on the style of wine.
For any specific questions on the wine making process or the English Wine Industry please visit the website of the English Wine Producers Association or contact them directly.