Ginger juice is made from fresh ginger and is used in marinades to give a subtle ginger taste without the bite of the fresh chopped pieces. Here is a simple method to extract ginger juice invented by my cooking associate, Gordon Wing: cut unpeeled fresh ginger into 1-inch (2½-cm) chunks and drop the chunks into a running food processor. When the ginger is finely chopped, pour the contents into a linen towel and squeeze out the juice into a small bowl. Or you can use your hands. If a food processor is not available, mash the ginger with a kitchen mallet or the side of a cleaver or knife until most of the fibres are exposed. Then with a linen towel or your hands, simply squeeze out the juice.