apple cider vinegar from apples

I am new to making ACV.  I have cut up apples (from very very old apple trees), covered them with water, a little sugar and weight to hold the apples under the water. I covered the jar opening with cloth and a rubber band.  They have a sort of vinegary - winey smell so I poured the liquid into glass gallon jugs with loose lids so they can breath. they all seem to be forming the mother very well. i've tried this method before but threw it all out when the mother formed because I thought it was mold. This time I know better. Very mucusy.

1. I am not sure when it is actually vinegar. I've tasted it and it did not seem like wine or vinegar but somewhere in between. How do I know when it is "done"?
2. How do you store it when it is finally vinegar? I watched a video    but she is making small batches and using it right away and then making more. I only have my apples in the autumn and am making gallons of it. I decanted some into a plastic vinegar gallon bottle and it was still giving off gas as indicated by the bowing of the bottom of the jug!

Could some you with more experience tell me if I am on the right track and answer my two questions?  Thank you so much

I am new to making Apple Cider Vinegar myself, so this is my little experience up to now:
Earlier in the year I made two bigger batches basically like in the video (less sugar). I stirred, the apple chunks (rather peels etc) sank down after a while, and after several weeks I strained everything and put it in bottles. I kept these in the kitchen to watch, opening them from time to time to let out pressure. However, not much built up.

When I was quite sure not much more was going on, I labelled the bottles and put them in the basement. The vinegar is not really tasty, I use it for cooking, to add to the chicken water dispenser and for cleaning.

Some weeks ago I made a second batch, this time smaller with sweeter apples (our own). After straining, I put in some of the mother culture from the first two batches (some stringy things).

After some maybe two weeks a beautiful mother formed. When I touched it, it sank down and another one formed. When I tried to taste the vinegarand touched the mother, it also sank down and a third one is forming right now. I "evacuated" the first two mothers in a jar.
The vinegar is really tasty this time. Not sure what had the most effect: Different apples, starter culture, good luck?

Anyway, I have read somewhere that all homemade vinegar has to age.

Some days ago I made a lot of apple sauce and with all the remainders I made a third batch of vinegar. This time I will be able to use a proper mother from the start.
I guess I will be self-sufficient on vinegar this year.

I will also try to convert one of the mothers to a Kombucha mother. I read that it is quite simple (just use it in the sugared tea, and after some cycles it should have adapted).

The apples contain sugar, the yeast, natural yeast if you don't add any will make the sugar into alcohol. That makes gas appear, just like making wine, the bubbles in the airlock on top of a closed vessel are CO2, produced by the yeast. The CO2 pushes out all the oxygen, so the wine/cider dousn't sour.
If you add O2(oxygen) wine or cider will get sour, thats because acetic acid bacteria change the alcohol into "sourness", acetic acid. Vin means wine in french and aigre means sour. Vinaigre is sour wine. Leave wine without a cork in time it will become vin aigre or vinegar.
So two types of micro organisms have to be present to make apple cider vinegar. Both of them just float through the air and will come onto fruit and start doing their job. Together they form this mother which is a handy thing because you can move it to speed the two processes up.
That's the theory behind it.
I  been doing it three years now. I cut the apples in pieces of 1 inch or whatever, remove the seeds and heart of the apple. Chuck it in a pan, pour water on it, put a cloth over the pan and make sure it is tight, so fruitflies can't come in. This year they did, it was a big mess with tiny larvae munching the apples, pops, hundreds of fruitflies. I made a brand new batch and kept it in a closed cupboard, far away from evil Drosophia.
And the best thing ever was that i read you can add herbs, and i did went to the herb patch, got dragon, it's so good it's just unbelievable how good that is. I shouldn't have shared it with you apple cider vinegar newbies in fact. But i have, because it's sooo good.

I make cider (hard cider) every year by juicing apples in an electric juicer.  I take the pulp and make vinegar.

I put the pulp into 5L plastic ice cream tubs which I can get from my work (catering).  I half fill the tubs with pulp, which comes from the whole apple including seeds/cores/etc, and then fill it up with water.  This is covered with a cloth and stirred every day until they fizzing stops and the pulp sinks to the bottom (about 2 weeks, depending on sugar content and kitchen temps).  I strain out the spent pulp through a muslin and put the liquic back into the washed tubs, covering again with a cloth.  These are stirred when I remember, but not usually daily at this point.  Generally a mother forms after several more weeks, though not always.  I mostly use this vinegar for cleaning, laundry and chicken waterers.

If a batch of cider made from full apple juice accidently turns to vinegar, it gets used in cooking or drinks:  much too tasty to waste on cleaning or chickens!  Though the vinegar from the pulp is also tasty, it's usually weaker--and I make plenty of it every autumn so I can afford to use it generously.  I've got five tubs on my counter in various stages of development right now.  One is already vinegar, two are recently strained, and another two were just filled with pulp and water yesterday.

Thank you for your replies.  I poured the liquid off of the initial batches following the time frame of the video, but the apples hadn't sunk to the bottom yet. I am trying to reuse them to make more and they did seem to form a mother on top. Thoughts? Should I just leave the vinegar with the apples for the whole 6-8 weeks? When it stops sending bubbles to the top you figure it is done? Thanks.

The apples may not have enough sugar in them to make another batch, but you can certainly try.  Give them a little taste:  if they're flavorless, compost them.  

I make it by first making apple wine by extracting the juice, adding sugar, and fermenting it to completion.

I then aerate the wine and add some active vinegar as a starter. I cover the lid of the pail with some cloth and leave it. I noticed that it's usually pretty much done when it stops stinking out your basement or wherever you keep it.

I read that the mother is what produced most of the vinegar and you're supposed to slowly add the wine over time because the mother needs to be in direct contact. Not sure if that is true or not. Anyway, I certainly ended up with great vinegar.