The Traditional Method is a way of producing sparkling wines via re-fermentation of a still wine in bottle. Perfected in Champagne and now practised the world over, it is the chosen means of production for the very finest sparkling wines..
Other sparkling wines, such as Prosecco and Asti, are produced via quicker bulk re-fermentation in tank. This process can yield delicious, youthful flavours (and is much faster and cheaper), but does not build as much complexity or longevity in the wine.
Read on to learn the steps involved in the Traditional Method.
How grapes are turned into juice has a crucial effect on the final wine. Sparkling winemakers mostly want to liberate the clearest, finest juice. This is achieved by pressing whole bunches slowly, over a number of hours in either a traditional basket press (pictured), a modern inclined sparkling wine press or a pneumatic press.
If grapes are pressed too hard, flavours and textures are extracted which will be detrimental to quality. For this reason, extraction is often regulated. In Champagne:
The first 512 litres of juice per tonne of grapes is called the cuvée and will be of the finest quality.
The next 125 litres are called the taille, and provide fruity, slightly less elegant wines that can be useful in blends.
Further juice is not used in wine production.
Other regions often adopt or adapt these guidelines from Champagne to ensure quality at the pressing stage.
The juice undergoes a first fermentation, producing a wine which will resemble a light, dry still wine with plenty of acidity. Juice is usually left to settle, so any solids that might add unwanted textures and flavours are removed.
The choices made now are a matter of style. These include fermentation temperature, the use of neutral stainless steel tanks or more characterful oak barrels, choosing to use native or cultured yeasts and whether or not to encourage the Malolactic Fermentation.
Different varieties, vineyard sites and even sub-blocks are usually fermented separately so that a winemaker can maintain the most flexibility when assembling the final blend.
Individual varieties from single vineyards sometimes make excellent sparkling wines and are bottled alone. It is much more common, though for producers to blend a number of these still 'base wines' together to produce a balanced, complex wine.
For instance, one or two exceptional blocks of Chardonnay from one good harvest may be bottled as a Vintage Blanc de Blancs.
The producer may then blend Chardonnay, Pinot Noir and Pinot Meunier from the rest of their production to make a 'Classic' blend. This could also be single vintage, but may contain reserve wine stored from previous vintages. In this case the wine may be labelled Non-Vintage.
Large production wines may have hundreds of components - size is no barrier to quality.
Once blending is complete, the wines are bottled in special pressure-resistant bottles. Specially-selected yeast and a carefully-calculated amount of sugar are added to the wine before bottling. After the bottles are sealed (normally with a crown cap), the yeast then consumes this sugar, producing CO2 which is then trapped inside the wine. Temperatures are kept low - around 13C - to achieve a slow, steady fermentation,.
The amount of sugar added determines the final pressure of the wine, which could range from three to six atmospheres. This affects the texture and mousse,
The yeast, having consumed all the sugar, die and form a layer of lees in the bottle.
The ageing of the wine on the lees of is the single most important step differentiating Traditional Method Sparkling Wines and sparkling wines produced by other methods.
As the dead yeast cells break down, they release a series of amino acids, proteins and complex aromatic compounds into the wine. This is called autolysis.
Ageing times of under 12 months have limited effects on flavour, so the minimum ageing time for Champagne is 15 months for Non Vintage and 36 months for vintage. The finest wines will spend a decade or more on lees.
Lees ageing is always carried out under controlled conditions, such as those found in the deep, cool and dark chalk cellars of Champagne.
Early attempts at producing sparkling wine via bottle fermentation came across a difficult problem - how to remove the yeast lees and leave a clear wine?
The solution begins with Riddling. Via a series of twists made whilst increasing the angle of the bottle towards the neck, the layer of lees is slowly moved until it collects just under the closure. Traditionally this was done by hand, and could take over a month with bottles being turned once a day on riddling racks.
Today the majority of wines are riddled automatically using a gyropallete (pictured). This completes the riddling of a cage of sparkling wine in around a week.
After the lees has formed a compact layer under the closure and the bottles are fully inverted, the wine can be disgorged. In its most basic form this involves carefully removing the closure by hand whilst re-inverting the bottle, allowing the pressure inside to shoot out the plug of yeast.
This disgorgement à la volée is still occasionally practised, but most Traditional Method Sparkling Wine is disgorged mechanically. The necks are frozen to encapsulate the yeast plug in a small amount of frozen wine. When the bottles are re-inverted, this ice plug shoots out of the bottle, ensuring no yeast re-enters the wine. When performed well, no additional wine is lost.
As a small amount has been removed from the wine, even if no dosage is to be added then the bottles are topped up with the same (or similar) wine. Disgorging introduces potentially harmful oxygen to the wine, so sulphites are usually added to prevent degradation. Low or zero-sulphite wines can oxidise especially rapidly.
Most Traditional Method Sparkling Wines receive a dosage at this time. This is a carefully-calculated amount of sugar, designed to help balance the wine. Amounts are low; Extra-Brut is 6g/l or under whilst Brut allows up to 12g/l (although many Extra-Brut wines are simply labelled Brut). The vast majority of wines fall into these categories, although sweeter styles such as Demi-Sec also exist.
Disgorgement is a very disruptive process, so the wine requires a waiting period of at least three months before being consumed. At this point, the wine will be very pure and fresh in style, not having taken on any further ageing characteristics.
Many producers will age their wines for much longer than three months before sale, especially for top cuvées. This stage of ageing introduces a very different character into the wine - read all about Flavour to learn more!