Bruschetta, in its purest form, is crusty bread grilled with a smear of olive oil and topped with fresh tomatoes and herbs marinated lightly in a simple vinaigrette. If you make a quality version, chances are you won't end up with leftovers. But should you do have bruschetta assembled and left over -- it won't store well. The moistness of the tomatoes will cause the bread to become soggy and create an unappetizing mush. You can store bruschetta topping successfully, though.
Storing the Topping
If you have extra bread and topping not yet assembled, store these ingredients separately. If the bread is already toasted, it might stay edible for an hour or two if you wrap it in foil; however, over time it will simply turn hard and inedible when stored. You're better off buying a new loaf and broiling or grilling it just before serving.
Make the topping with fresh tomatoes, herbs, vinegar and olive oil.
Place it in a airtight container until you're ready to serve. Do not leave the chopped tomato mixture out of the refrigerator for more than two hours.
Use it within three days to top freshly grilled or broiled bread.
Innumerable variations of bruschetta exist, including ones that are spread with an olive tapenade or ricotta cheese and then topped with herbs or other additions. These versions will suffer the same mushy fate as traditional tomato-topped bruschetta if stored for more than a few minutes. It's best to eat moist toppings on crisp bread immediately.