'Real' fudge requires a candy thermometer and if it's not calibrated correctly it won't work properly. I discovered the hard way that my thermometer was off, so it didn't set properly. The 'cheater' recipes using sweetened condensed milk or marshmallow crème don't require the specifics of candy making so are a little easier to pull off!
To 'calibrate' your candy thermometer, I would see what it reads when you put it into a pan of boiling water (Make sure the water is boiling good). Does it read 212? If not then you'll need to adjust accordingly. My thermometer read about 5 degrees low, so when I thought it was coming to temp it wasn't. I had to wait until it read 5 degrees higher (then subtract 5 degrees) and it was the proper temp. In the long run, I bought a new thermometer...
Last edited by kristijoy; 12-03-2014 at 01:29 PM.