I would like to turn you on to an Internet resource that I use quite a bit. As a cost conscience cook I don't like buying a bottle of some unusual vinegar, or spice that I will likely use once or twice before it goes bad. There is a very good chance that there is a good substitute for that unusual ingredient, but I'll be darned if I know what it is. In comes the Cook's Thesaurus. This very helpful website not only gives you the definition of your strange ingredient, but tells you what you can substitute for it. I used it today to make certain that I could substitute Jarlsberg for the Gruyere I could not find at my grocery store.