Chaptalisation is an enrichment process used across Europe and the world to increase the amount of alcohol in a finished wine by supplementing the natural sugars present in unfermented grape must before fermentation. It is a common response for consumers to be a little dismissive when learning about chaptalisation because of how it has been misused in the past by lesser producers. It is in no way an inferior practice when exercised within limits, however. Even great wine estates in Bordeaux use it. It is a winemaker’s tool.
Winemakers stumbled onto the enrichment process in the late 1700s but it was the French chemist Jean-Antoine Chaptal who concluded that the addition of beet sugar prior to fermentation could enrich wine in 1815. So the term Chaptalisation bears his name. Cane sugar later became an additional source of sugar for chaptalisation. Where grapes are grown in Europe determines how much a winemaker may enrich a wine under European law. Cooler climates, like those of Germany, are permitted slightly higher levels of enrichment.
German wine law does not permit chaptalisation for all categories of prädikatswein.