Champagne is unique in that it undergoes not one, but two alcoholic fermentations. This process simply uses yeast to convert the natural sugars found in the grape must into alcohol, with a bi product of carbon dioxide (CO2). Fermentation helps to influence the final flavours and aromas of the wine by contributing yeast like or ‘autolytic’ flavours and aromas.
The first fermentation happens in stainless steel (sometimes in oak), after the grapes have been pressed. The second fermentation happens later on in the bottle. Fermenting in Oak can add further oak derived flavours and aromas such as nuts, wood, and toast.
Malolactic fermentation (MLF) is an optional process (normally used) that transforms malic acid into lactic acid. MLF also influences the aromas and flavours by providing lactic flavours as well as lowering high acidity and creating a soft, creamy texture. Winemakers looking to create a fresh, crisp and fruity style of Champagne would avoid this process and only use stainless steel during both the fermentation and maturation process.
Clarification is the final process before bottling that ‘cleans’ the wine by removing impurities and ensuring the liquid is crystal clear. Wine makers can fine, filter or use centrifuging or crossflow filtration to achieve this. Lees (dead yeast cells that are left in the wine to add autolytic favours) are also removed at this stage. We are now left with ‘vins clairs’ or a ‘base wine’ which can now be used to blend and create a final liquid ready to bottle.
What Grapes are used?
There are 7 permitted grape varieties winemakers and growers can play with to create their blends in Champagne. The three main grapes we focus on are the following three:
Chardonnay (white grape). This grape is delicate and is used to add elegance and finesse to the blend. In its youth, it adds floral aromas and a mineral feel. It is the slowest to reach maturity and can age for the longest.
Pinot Noir (red grape). PN is the strength and body of the blend and also contributes red fruit aromas.
Pinot Meunier (red grape). PM matures the fastest and adds the ripe fruitiness to the blend.
Once the blend is chosen and created, the Champagne may not be bottled until the January following the harvest at the earliest.
To start off the second fermentation (which happens in the bottle), the winemaker needs to add a sweet solution known as the ‘liqueur de tirage’.LDT is a blend of base wine and cane or beet sugar along with yeast to kick start off that initial fermentation process again. That extra sugar is needed in order for the additional yeast to convert it again into further alcohol, and extra CO2. The CO2 is now trapped in the bottle and is the reason Champagne contains those all important bubbles. This process normally takes between 6-8 weeks.
Transvasage, this is the process of transferring the newly formed liquid into a different bottle, Transvasage is not allowed in Champagne. The bottle the LDT is added into and which the second fermentation happens in, is the bottle that Champagne must be sold in.
Once filled, the bottles are sealed with a polyethylene stopper called a ‘bidule’, which held is fastened with wire cage. The stopper allows oxygen to enter the bottle and for carbon dioxide to escape.
The wine will now undergo the maturation process (literally where the wine will now mature gracefully over a resting period). Top quality cuvees can spend decades maturing on the lees in the cellar.
There are many rules and regulations within the region and ageing plays a vital part in these regulations.
All Champagne = 15 months in bottle before release, of which 12 months maturation on the lees is required for non-vintage cuvees.
Vintage cuvees = 3 years on the lees.
European sparkling wine in comparison = 90 days in bottle.
Riddling and what happens at the end?
Riddling comes at the end of the maturation period .Known as ‘remuage’, this process causes the sediment (a mixture of dead yeasts and other thrown components) to collect in the neck of the bottle ready for disgorgement (the ejecting of said sediment which leaves the final wine clear)
Riddling can be carried out either by hand or by machines called gyropalettes. By hand, a ‘remueur’ (bottle turner) can turn around 40,000 bottles a day, with the bottles placed neck down in a wooden a riddling rack. The bottles are rotated by stages, with the objective is to collect the sediments within the neck of the bottle, leaving the wine crystal clear. Manual remuage takes 4-6 weeks and involves on average 25 turns per bottle, where as a gyropallate can hold up to 500 bottles at once, work 24/7 and take up to a week only.
After remuage, the bottles are neck-down (‘sur pointes’) and ready for disgorgement where the neck of the bottle is dipped into a chilled solution.. The sediment is now frozen and called a ‘plug’ which can now easily be ejected under pressure when the bottle is opened, with minimum loss of wine and pressure.
At this stage, the winemaker has one final attempt to alter the finished wine. Dosage is a LDT now know at this stage as ‘liqueur d’expédition’. The wine maker can use this opportunity to play with the sweetness level in the bottle by adding a final top up of LDE before sealing the finished wine with a the cork it will be sold under. The following amount of sugar per litre refers to the style being created.