backsweeten w/o stabilizing?
 

What do you guys think if I backsweeten my cider with 2 cans of concentrate after having crash cooled it in a keg? I'd just dump in and mix up the concentrate, no sorbate or sulfite. The temp would be about 40, though I could hold it a while at a temp lower than that to really halt activity. I doubt fermentation would start or if it did, come anywhere close to consuming the added sugars by the time I drink it.

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.