stuck fermentation

Hi yall

I have a cranberry batch that has been doing nothing for the past 5 weeks. I used Old Orchards Cranberry concentrate. This is my 3rd cranberry batch so I know it should be going strong by now. I've added in more yeast, nothing. I've added different yeast. Still nothing. I've pull out a small sample and experimented with that to get it to ferment. Nothing. I don't have a way to check ph levels But I suspect they are too high. I'm very weary of throwing Calcium carbonate in my batch though.

I don't know what to do. I've even pulled out a small sample and tried to get SOMETHING to grow in it. Still nothing.

and the concentrate had NO PRESERVATIVES? namely potassium sorbate...

cuz its either been preserved, or the pH is so far off the yeast can't do anything.

or all your yeast is dead, but I doubt that unless its 2 years expired and was stored in a tin shed all summer.