It will start fermenting however as long as you keep it cold it should be slow. However what yeast did you use?? if you used something like ec-1118 than back-sweetening with out stabilizing is a BAD idea. I prefer to pasteurize rather than add chemicals. Only way to actually kill the yeast.
- "It's all about time. You can't rush perfection. Time TIME TIME!!! You either need to pay on the front end or the rear. If the batch ferments out fast you need to secondary age or bottle age it. If it ferments out slow... months not weeks, then you don't have to age it nearly as long to get good flavors. Either way time is the key when making ciders and wines."