Champagne is a luxury item and can be very expensive so, what makes this wine different and how do those bubbles get inside the bottle? There are several ways in which bubbles can get in to the wine and its not by a bubble making machine. The method we are looking at it is known as the traditional method and this is the way all champagne has to be made. Other parts of the world also use this method but can not call it champagne, it has to be called sparkling wine but can state on the label that it has been made using the traditional method.
The grapes used will depend on the law of that particular region for example champagne uses a blend of three grapes, chardonnay, pinot noir and pinot menuier. The New World have made sparkling wine in the image of champagne and very often use the same three varieties.
The care starts in the vineyard and at harvest the grapes are handpicked to ensure they reach the winery in perfect condition and the skin is not damaged. The grapes are whole bunch pressed and the the stalks help filter the juice. The first pressed juice is the finest with high sugars, acids and low phenolics. This juice will be used for the top cuvee also known as Prestigee Cuvee or vintage.
The first fermentation takes place and this is to convert the juice in to alcohol, this will produce a still wine that is crisp, high acidity and moderate alcohol. This is the point the winemaker will blend the wine and this is one of the most skilful jobs. The wine has to go through the second fermentation which produces the bubbles, the winemaker has to understand the wine, how it will evolve and know what each component will bring to the finished product.
Once the wine is blended the liqueur de triage is added to the bottle which is a mix of sugar, yeast and agent to help the process. This creates alcohol and CO2, the gas is unable to escape which dissolves in the wine producing the bubbles. What you are also left with is the deposit of dead yeasts cells and although they would be harmless for you to consume it may not look very attractive. For this reason over time a process has been developed called riddling.
The riddling process was developed by Madame Veuve Clicquot, the process involves turning the bottle little by little. Starting horizontally it will be turned slowly so that eventually the bottle will be upright and the yeast deposit at the top of the bottle in the cap. Riddling was all done by hand and a skilled remuer could manipulate 30,000 bottles a day but would take up to least 6 weeks, whereas now this process is usually carried out by large machines called gyropalettes which only takes 6 days.
To remove this deposit the end of the bottle is frozen in brine the cap is released, allowing the frozen yeast solid to fly out (under pressure from the bubbles and controlled). This process is called disgorgement. The loss of liquid needs to be topped up and this is called liquer d’expedition which is a mixture of sugar and wine. The decision to be made at this point by the wine maker is how sweet they want to make their sparking wine and this will determine how much sugar is added in the mix. Once the liquer d’expedition has been added the cork is inserted and the wire mesh is fixed firmly holding the cork. The pressure of a bottle of sparkling wine is the same pressure as a bus tyre. The process of disgorgment to sealing with a cork is all one process.