I have a 5 gallon cider batch that I handpicked and pressed myself and it has been sitting in the secondary for about 6 months. It is about 9% abv. I put a cup of sugar in it last week, and it isn't doing anything so I'm confident the yeast is dead. I love the color and aroma but I want to sweeten it up some because its a little bitter for my taste. What is most recommended; sugar, apple juice concentrate, or something artificial? Also for those that have aged cider, I plan to bottle this week, but how long can it last before it starts to go bad?