Exploding Cider!!!!!!!!

[sconnie]

So here's what happened:
i started a gallon of cider on 9/1/06. Within a week and a half fermentation had stopped and i racked it to the secondary. I had a taste and it was very dry, so i decided to sweeten it up just a bit with some frozen apple juice concentrate. I killed the yeast with one crushed campden tablet, then the next day added just a little (3 oz or so) concentrate to mellow out the flavor. I bottled the cider on 9/25 and it seemed quite a bit better. I filled 4 bottles completely, but the last bottle was a little short, so i decided to add a tiny bit more concentrate and some water to fill up the space, thinking that the yeast was dead so it wouldn't matter. it was a very small ammout of juice that i added, so i didn't mark the bottle or anything, and i have no way of knowing which bottle had the extra juice.
So last night, at about midnight, i'm awoken by the a loud POP, and i find my room covered with yeasty cider and one of my bottles un-corked. SO it appears i didn't kill the yeast as i thought i did. I assume that the bottle that exploded was the one with the extra juice in there, but i have no way of knowing for sure. I put the remaining four bottles in the fridge, thinking that perhaps the low temp might knock out any yeast remaining alive in those bottles.
My questions are:
where exactly did i go wrong? and
what can i do to ensure the remaining bottles don't explode? Is the fridge a good idea?
thanks in advance for any advice

p.s. it was nottingham ale yeast if that makes any difference

 

[rod]

speaking from limited experience - i think you need potassium sorbate and the campden tablet together to stop the yeast

 

[Truble]

You could pasteurize it by putting the bottles into a pot, covering with water, and slowly bringing the water temp up to 140*F, hold for 10-15 minutes or so at 140*F, and then remove heat and allow to cool. The object is to bring the liquid inside the bottle up to 140*F, which will kill the yeast. Make sure that you have some head space in the bottles, though, as I believe an overfull bottle will explode if heated too much.

 

[Caplan]

As rod said campden won't 'kill' yeast. It'll just supress it enough with a decent ABV to help 'starve it death' in a bone dry cider (an FG below 1.000) and leave you with a clearer brew (with pectinase) for 'still cider'. You didn't mention a hydrometer reading but you back-sweetened it to taste, (more fermentables to help the yeast survive) and then added an extra slug of concentrate in one of them - my money's on that one that popped!
For the sake of a one gallon batch it may be safer (for you and anyone else in your house) to just dump them and start again but it's your call. Refridgerating them will slow the ferment down, but it won't stop it fully.