Hi Nicks90, I used brewing sugar and the cider was at shed temp of about 22, I will recarb the way you have suggested I suppose its all a learning curb and it is great to have the help of this forum. Thanks againIf you are adding granulated sugar and then it exploded everywhere, then there is a lot of co2 in suspension.
Was this taken out from your fridge? If so then its too cold and the co2 has reabsorbed in to the liquid and the sugar is acting as a nucleation point.
If it was chilled, what's it like at room temp?
Either way, the easiest way of adding more sugar to a partially carb'd brew without the sugar causing the existing co2 to come out of suspension is to dissolve the sugar in water and then add that to the bottles.
1tsp x number of bottles you are recarbing in to a jug.
Then pour boiling water in to the jug till it reads 10ml x number of bottles you are recarbing.
So if you have 15 bottles, add 15tsp sugar and top up to 150ml.
Don't add the sugar to 150ml of water, or you'll end up with about 170ml and then it will challange your maths and measuring ability!
Once it's dissolved, use a syringe or kitchen measuring spoon to dose 10ml of the sugary water in to each bottle. No sugar crystals = no nucleation
Then hopefully it will recarb. If it doesn't and you are absolutely sure the bottle tops were on tight - then I would suggest the caps need replacing.