Verjus has been cropping up in recipes recently. It's often recommended as an assist to wine or vinegar. It's great in rich sauces such as hollandaise. You might assume that verjus is a new product, another "do we really need this" item, as useful to cooking as a left-handed spatula. But verjus (or verjuice) has been around a long time.
The name comes from vert jus, that is green juice. It is the slightly acid liquid pressed from young fruit. This is usually grapes before they are harvested for wine but verjus can also be made from crabapples and other unripe fruit.
Verjus has a complex taste. There is the intense fruity flavour we associate with wine but with a medicinal undertone and a bite. Then, while it is acidic, verjus is not as intense as vinegar. Because of these in between qualitiesnot quite wine, not quite vinegarverjus is an intriguing substitute for both of these staples. It works particularly well when the oil or butter in a dish needs to be balanced with a strong flavour that has a delicate edge.
Verjus was once used a lot in western cooking, especially in the Middle Ages. It is still common to Middle Eastern recipes, particularly Iranian dishes.
I knew verjus was becoming fashionable when an American vintner started advertising red, white, and chardonay verjuice at exalted prices on the internet.
Nevertheless verjus doesn't have to be expensive. A half litre bottle costs only a few dollars in local Middle Eastern grocery stores.
Some recipes suggest replacing verjus with lemon juice but even that can be too strong. Verjus is subtle. Play around with this stuff. Try it in salad dressings or to deglaze a roasting pan. Sprinkle a few drops over rice just before serving. Splash it over grilled fish. It's good to have on hand for a little experimentation.