troubleshooting

I don't think it's weird at all, I can't tell the difference in mine either! I always have to get others to try out my batches to tell me if they are sweet or vinegary or what ever they taste, otherwise I just don't know! So my advice is to just ask others to taste it, if anyone is brave enough to try it.

Do you have anyone else who can taste them? I think that would be your safest bet. Can you compare the kombucha to store bought kombucha? Maybe having some and tasting both one after another can give you a sort of base line on where the flavors should be. It's probably best to buy unflavored kombucha for this as you are unsure about your first fermentation, but don't try and compare it too closely since store bought kombucha almost always tastes different from our homemade kombucha, but use it as a way to differentiate flavors better.

Yes! I am using old kombucha bottles with a narrower neck compared to bottles like GTs, and even got new caps for them, and it is so difficult to open them! I have to use a towel for extra grip every time! I thought that new caps would help since maybe the old ones are damaged or worn out in some way, but nope, no difference at all. But it's worth it to be able to use smaller bottles rather than the larger flip top bottles which are great but just not my preference. I also like the fact that I can open the screw top bottles a little bit at a time to let some carbonation out rather than all at once with a flip top bottle!

Yes you definitely can, I have done this with fruit flavored F2 that I thought was done, but upon opening I learned that it wasn't. Since it was still pretty sweet I didn't add any more sugar, I just left it out for about another 2 days, and then opened it and it was more carbonated than it was the first time.

I would think that if you didn't add more sugar and there wasn't that much sugar in it anymore like there was in my case, then it would become more acidic. But as long as there is either already sugar still in it, or you add more sugar, I don't think it will become more acidic than if you would have just left it out without putting it in the fridge in between.

I recently had to experiment with this because half of my F2's didn't fizz at all. I left them for like 2 days, opened them, and there was absolutely no pop, it was like I opened a bottle of water. I added some more sugar to them and left them for another 2 days, and 2 of them did get a lot of fizz, but the rest did not. I am not sure what I did wrong here, but I can say that it works, even though half of the ones I added sugar to didn't fizz, the other half did! So it does in fact work!

Also, at that point, I didn't care to measure how much extra sugar I put in, I just poured a little bit in each bottle.

From my understanding and experience, yes. Even if you put it in the fridge but decide that you want it to ferment longer, you can. Just keep in mind that it will take it a bit to warm up to room temperature and to ferment to the point you want it to.