Gastrique is caramelized sugar, deglazed with vinegar, used as a flavoring for sauces.

To this a little fond (stock) may be added. It is used to flavor sauces such as tomato sauce, savory fruit sauces, and other sweet and sour sauces such as the classic orange sauce for duck à l'orange.

Nowadays, the term is frequently used to refer to any thus-flavored sauce itself, e.g citrus gastrique, mango gastrique.

An agrodolce

Agrodolce

Agrodolce is a traditional sweet and sour sauce in Italian cuisine. Its name comes from "agro" and "dolce" . Agrodolce is made by reducing sour and sweet elements, traditionally vinegar and sugar. Sometimes, additional flavorings are added, such as wine, fruit, or even chocolate. The sauce is...

 (sweet and sour) is a similar sauce found in Italian cuisine

Italian cuisine

Italian cuisine has developed through centuries of social and political changes, with roots as far back as the 4th century BCE. Italian cuisine in itself takes heavy influences, including Etruscan, ancient Greek, ancient Roman, Byzantine, Jewish and Arab cuisines...

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