What is ‘traditional method’ sparkling wine?
Ever wondered what the difference is between Champagne and Prosecco? It’s not just about where they come from or what grapes they are made from…
the chemical equation
Champagne is the best known region in the winemaking world for making sparkling wines using the ‘traditional method.’ So much so that it is also called the ‘methode champenoise’ as well. In the same vein, Prosecco is probably the best know region producing wines made with the ‘Charmat’ method. For both wines, one important (and some would say magical) chemical equation is key…
Sugar (grape juice) + yeast = alcohol + carbon dioxide gas
Traditional Method
Grapes are harvested, pressed to get the juice out, and then fermented into still wine. The vessel used for fermentation can have an impact on the final wine, but we’ll leave that to discuss another day! Most importantly for this fermentation – the carbon dioxide is allowed to escape into the atmosphere, so we’re just left with a still wine at the end.
Once you have a still wine, you then bottle it – but crucially – you put into each bottle an additional injection of yeast and sugar, and then stopper it closed tightly. For the super geeks out there this injection is called the ‘liqueur di tirage’ or ‘liqueur d’expedition’.
…continued
This addition of yeast and sugar will mean that the wine inside the bottle will go through a second fermentation (our magic chemical equation) but this time the carbon dioxide will have nowhere to escape to, so it dissolves into the wine – and in due course will become the magical bubbles when the bottle is eventually opened. This is one of the reasons why traditional method sparkling wines come in thick glass bottles – they have to be able to withstand the increased pressure inside from the dissolved CO2. A normal bottle of traditional method sparkling wine bottle holds about six bar pressure – roughly the same as a London bus tyre.
Back in the early days of producing wine this way, Champagne winemakers were often at risk of bottles exploding at random, until thick enough glass was produced to withstand the pressure. Some might like to know that the method of making thick enough glass was discovered in England – making Champagne winemaking possible!
…flavours
Anyway, back to our bottles. Once the secondary fermentation has taken place, the bottles are normally then left to rest for any number of months, or years. This time resting has an impact on the flavours and aromas of the final wine – as the dead yeast cells break down and the wine takes on flavours from this like bread, toast, brioche… this is called ‘autolysis’. This is a key marker of traditional method sparkling wine. The longer the bottle ages with the yeast in contact with the wine, the more pronounced these flavours and aromas will be.
charmat method
Grapes are harvested, pressed to get the juice out, and then fermented into still wine. So far the same. Although different grape varieties, different fermentation vessels will impact the end result – let’s stick to method only here!
Once you have your still wine, you then put it back into a large tank which can withstand increased pressure. Then yeast and sugar are added – for the all important second fermentation. The tank is closed, and the fermentation takes place – again the carbon dioxide being trapped inside. The difference with traditional method here is the volume of liquid – the wine in the charmat tank will have a lower level of yeast contact, and less autolysis. Winemakers also will stop this fermentation with a lower pressure level – more like two and four bar, and with some residual sugar remaining (before the yeast has guzzled it all) – something like 10g/l – which is why sometimes prosecco will taste less dry on the finish on the palate.
Once the wine has reached the desired pressure, it is then bottled under pressure, to maintain the bubbles.
traditional vs charmat
Both methods make lovely wines, but for our grapes at Wiston the traditional method – while a lot more work, a lot more costly and a lot longer in the making – is best to produce the very best sparkling wines we can from our part of Sussex and the South Downs. We love the impact the autolysis makes on the finished wines, even if it does take several years longer!
Come and discover them for yourselves and see the production in action.
