The reason vodka is used in cooking, especially with things like tomatoes, is for its lack of flavor. The vodka brings out flavors in other things. Some flavors are water soluble, some are fat soluble, and some are alcohol soluble. What that means is that you need one of those substances to taste that flavor. There are flavor compounds in tomatoes that are only alcohol soluble. You will never taste them unless booze is present. Lots of recipes that have tomatoes incude wine, but wine has a lot of flavor itself, so if you just want the tomato flavor then vodka is perfect because it has little or no flavor.