Since the herbs and jar-packing specifics will vary from kitchen to kitchen, feel free to use additional apple cider vinegar to top off your jar. This recipe is more of an art than a science, so exact amounts don’t necessarily apply when it comes to the vinegar.
This doesn’t need to be refrigerated, but you can store it in the fridge after the initial month of fermentation.
Like most fermented foods, the longer it sits, the stronger it gets. However, I’d recommend using it within 3 months or so (after that initial fermentation month). You don’t need this stuff laying around for years, but rather it should be enjoyed in the season you made it.
And, of course, if the jar or lid show any sign of rust or mold, then it’s time to toss it and make a fresh batch (though this has never happened to me).