How champagne is made
Harvest and picking
In Champagne harvesting is still done by hand. Not only does this allow us to select the best bunches of grapes, it also means that we can send whole bunches, still attached to the stalks, off to the press house.
We use a type of press called a « Bucher »: it consists of a horizontal cylinder with a membrane inside that inflates and deflates over a period of 4 hours which is the time it takes to complete the pressing.
We load 4,000 kilograms of grapes at a time into the press and the juice runs off into a container called a “belon”. At this stage, the juice is called “moût.”
From each load of 4,000 kg we extract 25.50 hectolitres (2,550 litres) of moût which is separated into:
- Cuvée: 20.50 hectolitres (2,050 litres). This is the purest juice with the highest sugar content and the highest tartric and malic acid content. It produces wines of great finesse, with freshness on the tongue and good ageing potential.
- Tailles: 5 hectolitres ( 500 litres). The tailles are lower in acidity and have a higher content of mineral salts, particularly potassium. They give pleasant, fruity wines but with less capacity for ageing.
The juice is left to settle for 12 hours before we proceed to the "débourbage" which involves separating the clear juice from the “bourbes”: the sediment and the tiny particles in suspension in the juice.
The clear juice is then taken to the vat house where we start the first alcoholic fermentation.
Sugar and specially selected yeast cultures are added to the moût. The sugar is converted into alcohol by the action of the yeast, a process that also yields carbon dioxide gas and heat. After about 8 days the fermentation is complete and the moût has been transformed into still wine.
Next, the wine is racked several times to remove any sediment and traces of dead yeast so that the wine is perfectly limpid.
The acidity of the wine is reduced by converting malic acid into lactic acid through the action of specific bacteria.
The clear wine is then left to rest in tanks for 3 months.
Blending involves mixing together a large number of still wines (vins clairs) from different villages, from different grape varieties and from different years. In most instances we use all three of these variables, but sometimes we may decide to work with just one, for example:
- to make a vintage champagne we only blend still wines from a single year’s harvest.
- to make our Grand Cru - Blanc de Noirs and our Grand Cru - Blanc de Blancs we use a single grape variety : Pinot Noir and Chardonnay respectively.
- for "Les Petites Vignes", we use grapes from just one village and from just one plot.
Blending usually takes place in February; we taste the wines in each of the tanks and then decide exactly how we need to blend them in order to produce our full range of champagnes.
Bottling usually takes place in March. At the same time as bottling the wine we add:
- a ‘liqueur’ which contains 24 grams of sugar per litre, precisely the amount that will produce 6 atmospheres of pressure in the champagne at the end of the second fermentation.
- more yeast. The yeast breaks down the sugar and produces carbon dioxide gas. This is the second fermentation that creates the bubbles in the champagne.
When the ‘liqueur’ and the yeast have been added the bottles are sealed with a crown cap and a small plastic stopper which collects the yeasts cells that are used up and die during the fermentation.
The birth of the bubbles and ageing in the cellars
The sealed bottles are laid down horizontally. This is very important because the yeasts cells form a deposit along the whole length of the bottle and this maximises the amount of yeast that is in contact with the wine.
The ‘Prise de Mousse’ or Birth of the Bubbles takes about 6 weeks but this will vary a little depending on the temperature of the cellar; ideally, it should be about 150 C. Slow and steady fermentation is one of the secrets of producing tiny bubbles.
The yeast which helped create the bubbles has another vital role to play: as it is consumed and dies it releases nitrogen which contributes to the development of an array of aromas in the wine.
Once the wine has aged sufficiently the yeast cells have to be made to slide down the inside of the bottle towards the neck in an operation called riddling (“remuage”). To do this we use “gyropalettes”: machines which turn and lift the bottles little by little until, after about a week, they are in a vertical position but pointing downwards. The bottles are now said to be “sur pointe”. For large bottles (jeroboams and special magnums) we still do this operation by hand, turning the bottles, just an eighth of a turn at a time, until they are vertical – this takes up to three weeks.
These days disgorging is done "à la glace": the end of the neck of the bottle is plunged into a bath of refrigerated liquid at -240 C. An ice cube forms inside the bottle, trapping inside it the yeast sediment which is resting on the cap. Then the bottle is “disgorged”: the bottle is turned upright, the cap is removed and the ice cube shoots out under the pressure of the gas inside the bottle. About 1 kg of pressure, and a little wine, is lost during this process.
We top up the bottle with a little champagne and what is called a "liqueur de dosage": usually liquid cane sugar. The amount of sugar or “dose” varies according to the type and style of champagne one wants to produce.
After the “dosage”, a cork is finally put in the bottle and is held in place by a wire cage to prevent it being forced out by the pressure in the bottle.
The wine is now allowed to rest before the bottle is labelled and prepared for sale. This resting time is needed for the wine to recover from the shock of the disgorging and for the liqueur to thoroughly mix with the wine.