Understanding the differences between Champagne and sparkling wine can be confusing to consumers. While in one sense it’s simple to understand that only wines made in the Champagne region of France have the right to be called “champagne” but that doesn’t really say much about the difference of what’s in the bottle.
There’s definitely a difference, and it comes from the different winemaking processes and, as always, the different influences of the ‘terroir’ on the still wines used.
Champagne beginnings
All sparkling wine and champagne begins as a still, or non-fizzy, fermented base wine. To make the “base” wine in Champagne winemakers blend many still wines from different vineyard locations– sometime up to 70 different still wines – in a process called assemblage. The thinking behind such a massive blending exercise is that winemakers can achieve more consistency and higher quality (while diminishing the contrasts between different still wines) if they blend more wines together- sort of the "sum is greater than the parts" theory.
Once blended, winemakers put the wine in bottles and add an exact measure of a sugar and yeast mixture to this base wine. This mixture is called the liqueur de tirage and its interaction with the base wine results in a second fermentation in the same bottle. The amount of sugar used at this stage will impact the style of the mousse, e.g. slightly fizzy or creamy, etc.
After adding the liqueur de tirage the winemaker seals the bottle with a bidule, which is a small crown cap (like a beer bottle cap closure) that has a plastic cup underneath that fits snuggly into the bottle's neck. This little plastic cup will ultimately capture the fermentation sediment.
Second Fermentation - here comes the fizz!
The by-product of the second fermentation is some additional alcohol and carbon dioxide, or the bubbles. As science dictates, where there’s CO2 production there’s additional pressure build up. This is why Champagne/sparkling bottles are so much thicker than regular wine bottles - they have to withstand the pressure of the fizz!
Temperature plays an important role in the second fermentation as does the length of time the fermentation takes to complete. A cooler, long fermentation yields finer bubbles and more complex flavours in the finished wine.
When the second fermentation is finished the dead yeast cells (lees) break down in a process called autolysis. At this point the winemaker determines how long the wine will remain on the lees, a decision that also affects the style of the finished champagne since longer yeast contact can add complexity to the flavours. However, eventually the lees must be removed without allowing the CO2 to escape and oxidation of the wine to occur.
Riddling and Disgorgment
Removal of the dead yeast sediment (lees) is achieved through a process called riddling or remuage (incidently a process pioneered by the widow Cliquot – a.k.a. Veuve Cliquot) which puts the wine in contact with the yeasts while slowly moving the sediment down to the top of the bottle into the little plastic cup behind the crown cap (the bidule).
Traditionally riddling was done by hand, and for this bottles were placed neck-first in holes in an A –framed riddling rack. The bottles started out positioned at a slight angle, then the “riddler”, or the person responsible for turning the bottles, turned each bottle a little bit everyday and with each turn increased the bottle angle gradually so the sediment gently collected in the neck (in the bidule) against the crown cap. Even today, the process is complete when the bottle necks are nearly upside down.
The point of the riddling exercise is to position the sediment for easy removal at the top of the bottle. So with the sediment/lees collected in the neck, the winemaker now places just the very top of the neck into a freezing brine bath to freeze the liquid and sediment: this forms an ice plug at the top. This makes it possible for the winemaker to remove the crown cap and the frozen plug with the sediment. When the bottle is opened, the plug shoots out 'BANG!' – and the champagne is officially disgorged. (See the video below)
After disgorging the bottle, the winemaker must quickly top up the bottle with a dosage (a mixture of still wine and sugar). This dosage will also determine the sweetness -- or dryness -- of the final wine.
The dosage is the last step in the méthode champenoise process of making sparkling wine. Once added the bottle is immediately corked and a wire hood is put on to secure the cork.
This process, from assemblage through to dosage is what is known as the méthode champenoise, or the Champagne Method, and one very important distinction between this method and other sparkling wine production methods is that the wine never left the original bottle. In other words, the second fermentation occured in the same bottle that you buy from the retailer's shelf.
Many sparkling wines are made according to the Champagne method, but still do not have the right to be called Champagne. This is simply because a wine has to be made IN the Champagne region to have the right to be called Champagne.
Next we’ll look at how to open and appreciate Champagne, and also the other ways to make sparkling wine. And if you're keen to see how champagne is disgorged, check out the YouTube video below. The video is of a disgorgement with Jeraboams (really big bottles). Because of the pressure that builds up in these large bottles, they don't use a crown cap for the second fermentation but use a cork and metal seal. Take a look. You'll definitely hear the BANG!
Contributed by Sarah Mayo (TLN Editor)
