Verjuice (from Middle French vertjus "green juice") is a very acidic juice made by pressing unripe grapes, crab-apples or other sour fruit.[1] Sometimes lemon or sorrel juice, herbs or spices are added to change the flavour. In the Middle Ages, it was widely used all over Western Europe as an ingredient in sauces, as a condiment, or to deglaze preparations. It is still used to some extent in the American South.
It was once used in many contexts where modern cooks would use either wine or some variety of vinegar, but has become much less widely used as wines and variously flavoured vinegars became more accessible. Nonetheless, it is still used in a number of French dishes as well as recipes from other European and Middle Eastern cuisines, and can be purchased at some gourmet grocery stores. The South Australian cook Maggie Beer has popularised the use of verjuice in her cooking, and it is being used increasingly in South Australian restaurants.
Modern cooks most often use verjuice in salad dressings as the acidic ingredient, when wine is going to be served with the salad. This is because verjuice provides a comparable sour taste component, yet without "competing with" (altering the taste of) the wine the way vinegar or lemon juice would. Its acidity is very mild.
Verjus, called husroum (حصروم) in Arabic, is used extensively in Syrian cuisine. In Syria, much of the production of husroum is still done over the course of several days by female members of land-owning clans -- even if many of them live in cities. The husroum produced during this time will be distributed to various households within the extended family and used throughout the year. The same is true for the production of olive oil and tomato paste.
Verjus, called ab-ghooreh in Persian, is used extensively in Northern Iranian and Azerbaijani cuisine.
The authors of The Medieval Kitchen: Recipes from France and Italy write that the grape seeds preserved in salts were also called verjus during the Middle Ages.
In the regional French of Ardèche, a cider fermented from crab apple juice is called verjus. In medieval and early modern English cookery texts "verjuice" sometimes means apple juice or crab-apple juice.