Verjus is the tart, fresh juice of unripe wine grapes. It is a culinary ingredient indigenous to the world's wine-producing regions and is used in sauce making,  poaching fish and meat, and dressing lettuces, vegetables, and fruit. Verjus means green juice because it's made from fruit that has yet to ripen fully -it's green. It adds acidity to foods, an important component in food and cooking.  This product must be refrigerated after it is opened. It lasts 4 weeks once opened.