Does anyone know if an opened bottle of distilled water goes bad? I've had a one gallon bottle for almost a year now and I've only used 1/3 of it. I keep it in a dark cool place but I'm wondering if there's an expiration on opened bottles or if the opened bottle shoudl be discarded after a certain time period. I don't see any bacteria or any other type of growth in my humidor or on my cigars and I don't believe they're introducing a bad taste to my cigars. How many weeks or months do you wait before replacing your bottle of distilled water?