I defrosted some peaches with the intent of possibly making jam. They are very syrup-y. Is it still possible to make jam from them?--Will it still set up?
Mmmm, was it frozen as is or where they preserved in syrup? If they were raw they should be fine since you need the jucie anyways, but if they were in syrup I don't know. The extra sugar might upset the pectin. I hope someone eles can chime in. I freeze all of my fruits raw. It only changes the color.
Frozen raw you can most certainly make jam from them -- I do this quite frequently, freeze fruit for later jam-making. If you sugared them before freezing you will have to estimate how much to correct for that, and the product may be a bit more 'surprising' in consistency than you're used to, but oh well.