How long does home brewed kombucha last in the fridge?

I made kombucha and put it in the fridge less than a week ago, and it has a bit of a weird taste. It's as if the herbs I used to flavor them were left in and either lost their taste or have too much of their flavor, but they were not left in, I took them out. Is there a limit to how long kombucha can stay in the fridge? Does it matter if it was opened or not? My thought is that maybe because I opened all of them to taste, they lost their freshness?