When someone orders a "dirty" martini that means that they want olive juice added to their drink. Let's think about this for a second. If you crush up olives, you don't get olive juice. You get olive oil. So what is that stuff they call olive juice?

The liquid you find inside jars of olives is considered olive juice, but it's technically pickled brine. That's right, pickled brine. Pickled brine is just a salt and water solution and has an olive flavor because this is the liquid that comes in the jars that olives are stored in.

So when someone orders a dirty martini, what they really want is a little pickled brine added to their gin or vodka, dry vermouth, shaken or stirred and served up in a martini glass, garnished with an olive. Therefore, technically it's pickled brine that makes a martini dirty, not olive juice.