Chaptalisation

Named after Jean-Antoine Chaptal, Napoleon’s minister of the interior, who promoted the practice in the early nineteenth century — though he did not invent it.

It attracts more suspicion than it deserves, largely because "adding sugar to wine" sounds like something else entirely.

Sugar is added to the must before or during fermentation. Roughly 17 grams per litre yields about 1% additional alcohol by volume.

Because it is added before fermentation completes, the yeast metabolise it along with the grape sugar. A dry wine that was chaptalised is exactly as dry as one that was not.

The purpose is to reach a viable and balanced alcohol level in a season where the fruit did not accumulate enough sugar of its own — historically a routine problem in cool marginal regions.

EU rules divide the wine-growing area into zones and permit enrichment only in the cooler ones, with caps on the permitted increase. Warmer member states generally may not chaptalise at all, and may instead be permitted acidification, which the cool zones are not.

Alternatives to added sugar include concentrated grape must and rectified concentrated grape must, which achieve the same end from grape-derived material.

Understanding it removes a common source of unwarranted suspicion, and it explains why the same practice is legal in one country and prohibited in the next.