I was in Champagne last week visiting Marc Chauvet and needed to get to the bottom of that often asked question about the size of bubbles. The “prise de mousse” as they call it comes during the secondary fermentation in bottle when extra yeast and Champagne grape juice are added to the already finished, first-fermented still wine. The new yeast feeds on the new grape juice converting it to alcohol and CO2 gas. Now here’s the cunning bit - the bottle is sealed so the gas cannot escape and remains dissolved in the wine. Hey Presto - sparkling wine!

It is a tricky process as the new yeast is introduced into an already alcoholic and quite acidic medium, so quite hostile in fermentation terms. To ensure a risk-free secondary fermentation a high temperature of 20°C is needed so it takes place at ground level in warmer conditions. The “prise de mousse” can be quickly over in 10-14 days. This is the low risk version.

At Marc Chauvet they do all this in the deepest part of their cellars where the temperature is a constant 11°C and the secondary fermentation can take anywhere between 2 - 3 months. It’s a lot riskier and particular care must be taken with yeast selection, but the upshot is, the longer it takes, the finer the mousse. So now we know - including me.