If you are brave and you've got time, you can simmer a bone or meat broth along with some root vegetables.
If I cook more, I pour into 300 ml plastic bottles and keep in the freezer. This is the quantity needed for cooking the Romanian mici, but you can use it for other dishes as well.
It's also perfectly OK to use water instead of broth - sparkling or still, either way. I tried it and I didn't feel much difference.