I'm seeing more and more recipes calling for white balsamic vinegar. I did actually buy some once for a recipe, but the price was breathtaking and I'm not anxious to repeat the experience unless there's a good reason to do so. From what I know of regular balsamic vinegar, I can't even figure out how you make a white vinegar and still be able to call it 'balsamic.' What is this stuff? How's it made? Does it bear any relationship to traditional balsamic vinegars? Are there good substitutes for it in cooking, salad dressings, etc.? Thanks!