Using fruit...

I have an experimental batch of cider, using cherries. I hear that if they are in there too long, the contents may become sour. If this is the case...which it seems to be heading that way, is their anyway to sweeten this batch without dilution?

You could use lactose (which doesn't ferment), you could back sweeten with more cider, sugar, honey or other fermentable sugars and then use campden tabs or pasteurization to kill the yeast. If you want still cider campden tabs are the easiest because you can add sugar to taste, add the tabs and then bottle the next day. If you want sparkling cider you will have to Pasteurize after it carbs. For a "how-to" search the forum and you will find the steps.

Thanks!

Camden tablets alone won't kill the yeast. If you add too much sugar and only use Camden tablets if the bottles get warm enough they will eventually explode.