As the grapes for the 2021 harvest come in, thoughts turn to the subject of chaptalisation. Have you any idea what it is?
Chaptalisation is the permitted addition of sugar to increase the alcohol in wines. During fermentation, the yeasts eat the sugar and that produces alcohol. The amount of sugar in the unfermented grape juice (or must as we call it) will determine the level of alcohol in the final wine.
So what if we have a really tricky year and when the grapes come in they’re not very sweet? Well, that’s where chaptalisation comes in. Under certain conditions it’s permitted by the appellation authorities to increase the potential alcohol of wines by adding sugar before fermentation.
It’s probably fair to say that growers pushing for high volume are those most likely to add sugar.
In the north of France the addition of beet sugar is the norm whereas in the south of France they use concentrated grape must. And yes, you might ask why on earth growers in the south where there is tons of sunshine would ever need to add sugar.
It takes just under 17g of sugar per litre to create 1% of alcohol. So if your juice came in with a potential alcohol of say 10% (the minimum specified in the Vouvray appellation is 11%) then you’d add 17g per litre of juice and if you were looking to have a finished wine with 12%, you’d add 34g of sugar per litre.
Chaptalisation has been practised in France since the end of the 18th century although it’s quite possible it was done before that time. The chemist Jean-Antoine Chaptal is regarded as the one who introduced the idea in 1801 in his book ‘L’art de faire, de gouverner et de perfectionner les vins’.
It’s highly controlled in France and in some cases, the INAO will only give authorisation if the final wines would not meet the minimum alcohols specified in the appellation legislation.
There are other ways of increasing alcohol in wine. Reverse osmosis can be used to remove water from the must leaving behind a higher concentration of sugar which in turn will give a higher alcohol wine.
The last year where we saw quite a bit of chaptalisation was in 2013. It seems likely that this year will be similar. It’s said that the price of sugar has gone up 10% in recent weeks!
For those who live locally (particularly around Amboise), it’s interesting to know that Jean-Antoine Chaptal bought the Chateau de Chanteloup at auction in 1802 (he was Minister for the Interior under Bonapart) and he cultivated beetroot for the production of sugar in the surrounding park!
