Sour Cherry jam

I've made jam in the past, but this year I'm trying to experiment with fruit I've not used before and different combinations.  There are so many amazing variations out there now to get inspiration from, I could spend a whole day surfing the web just for jam and jelly ideas!
Friends of mine have a fabulous cherry tree on their front lawn.  I've never worked with sour cherries before, but have fond memories of my Aunt Eileen in her kitchen making cherry everything from her own trees.  So I went to pick cherries with Amy and Scott - the cherries wouldn't have lasted another day they were so ripe!

If all goes according to history, Scott predicts a bumper crop next year.  I'm keeping my fingers crossed.