Fish sauce is usually associated with specific forms of Asian cooking, but it can add real depth to many dishes without making them taste fishy. Photo by Greg.
I originally came across this tip reading Edward Lee's fantastic cookbook, Smoke and Pickles. In it, he suggests that using just a few drops of fish sauce adds a depth and an umami boost to almost any sauce or gravy you make. And he's right. Vietnamese and Thai cuisine aren't the only ones to use this techinique. Many Italian red sauces start with a bit of melted anchovy to achieve a similar effect. And most of us have thrown in a dash of Worcestershire for the same reason.
But fish sauce adds a certainly quality even those can't quite touch. As Edward Lee puts it:
I describe it as adding age or adding history to a dish, in the way that things like bourbon and cheese get better with age.
So give it a try. And don't worry. You'll only need a splash for most sauces and they won't taste fishy at all.