A huge topic. I conducted a simple experiment which I’ll explain later. Firstly, a comparison of residual sugar levels (RS) i.e. the sugars left in wine after the alcoholic fermentation has finished, of German still wines and champagne. It is measured in grams per litre (g/l)
Champagne Brut Natur < 3, Champ. Extra Brut < 6, Brut < 12.
German wine Trocken (Dry) < 9, Halb-trocken < 18
Why this experiment? When I run tastings the criticisms of champagne are that it is too acidic and/or too dry whilst the criticism of German wine is that it’s too sweet. The respective grades above show that a wine in the driest German wine category could be more than three times as sweet as the wine in the driest champagne category. Which, on the face of it, supports the criticisms.
Now it starts to get complicated – or interesting, depending on your point of view. Firstly, we can’t taste any sweetness under 4 g/l. I experimented with a water/sugar mix and whilst my wife couldn’t taste sugars at 4g/l., she could at 9 g/l. So far so good. But wine is not water.
Tannins (in reds), light body and acidity enhance the dryness of wine; a fuller body and alcohol will make a wine seem sweeter. German Riesling is a light and notably acidic wine so that high sugar level appears less on tasting. In fact, if it didn’t have that sugar it would be unacceptably dry to many palates. Champagne’s acidity and lightness will enhance its dryness which may be why Brut Natur seems too dry for some palates and the added final sugar dose is required not just for fermentation. It also explains why the fuller bodied styles of vintage champagne are generally well received.
And just to muddy the waters some more. Article 58 of EU sweetness levels – for sparkling wines only – state that “the sugar content may not differ by more than 3 grams per litre from what appears on the product label”. I’ll leave you to work out how that could make Brut Natur, Extra Brut and Brut meaningless as guides.
[Richard: received opinion seems to be that we all taste differently. I know I find more sweetness in a wine than Geoff does, which is a shame as I have a palate which favours savoury tastes. I must try adding salt to red wine which apparently adds flavour. Perfect lockdown experiment.].