Addition of sugar in various forms to fresh grapes, grape must, partially fermented grape must, young wine (not yet fully fermented) and wine. For this purpose, the terms alcohol increase, improvement, chaptalisation or harvest improvement are also used. 17 to 19 grams of sugar per litre of wine increases the alcohol content by about 1% vol. However, this process has nothing to do with sweetening a wine (increasing the residual sugar) or sprit (adding alcohol to the finished wine). The aim is to increase the natural alcohol content of the wine by fermenting the additional sugar.
Due to the EU wine market regulation (GMO) valid from August 2009, there have been changes in the guidelines. The maximum limits vary depending on the wine-growing zone. The maximum amount of enrichment in zone A (e.g. Germany except Baden) is a maximum of 3.0% vol (until 2008 it was 3.5), in zone B (e.g. Germany Baden, Austria) 2.0% vol (until 2008 it was 2.5), and in zone C (e.g. Italy, France, Greece, Portugal, Spain) a maximum of 1.5% vol (until 2008 it was 1.0). In years with extremely unfavourable weather conditions, an increase of 0.5% vol can be requested.
Various means or processes are permitted, whereby the application of a particular method/means excludes the others. The first form is the addition of sugary agents. Concentrated grape must (but not grape must), RTK (rectified concentrated grape must) and sucrose (beet sugar) are permitted. The second form of enrichment is a concentration (removal of water) of grape must(osmosis) and wine (freeze concentration). However, a concentration may not result in a reduction of more than 20% in the initial volume; or the natural alcoholic strength by volume (total alcoholic strength by volume of wine before any enrichment) may be increased by not more than 2%. The use of sucrose (dry sugar) is generally permitted in wine-growing zones A and B, but only in certain countries in wine-growing zone C. It is not permitted in certain departments of France, as well as in Greece, Italy, Portugal, Spain and Cyprus
The total alcoholic strength by volume of fortified wines without geographical origin (formerly table wines) is limited per wine-growing zone to a maximum of 11.5% vol in A, 12% vol in B, 12.5% vol in C I, 13% vol in C II and 13.5% vol in C III. By way of derogation, red wines may be fortified to a maximum of 12% vol in A and 12.5% vol in B. For wines with geographical origin, i.e. country wine(wine PGI) and quality wine (wine PDO), in contrast to the past no value is specified. However, the EU member states are obliged to set maximum limits. An enrichment has (unlike in the past) no effect on the limits for sweetening. For the quality grade Prädikatswein, enrichment is prohibited in Germany and Austria (here also the quality grade Kabinett) according to the laws of the federal states. See specific values under the countries.
Complete lists of the numerous vinification measures or cellar techniques, as well as the various types of wine, sparkling wine and distillate regulated by wine law are included under the keyword vinification. Comprehensive information on wine law can be found under the keyword wine law.