Verjuice, or verjus in French, is an acidic juice made by pressing unripe grapes. Widely used in the Middle Ages, verjus has become less common since. French cooks still use it to degleaze or marinate preparations, and as an ingredient in sauces and salad dressings. When accompanying dishes with wine, verjus is a smart choice because it does not compete with wine the way vinegar and lemon juice do.Family-owned Domaine du Siorac has made wine and verjuice for nearly 200 years. The estate is in Périgord, France's top gastronomic region.