I attempted strawberry freezer jam a couple years ago and had let the berries sit in the fridge too long. It was a bit of a waste as the jam turned out fairly sour. I've been hesitant to make jam again since then.
I let the berries sit in the fridge for a day to thaw out naturally. They were a bit mushy, but not as bad as if I had tried to thaw them out quicker. Which really didn't matter so much since I was going to mush them up anyway. I did it the lazy way and put the berries in the food processor instead of mashing them myself.
Then I just followed the directions that came with the pectin. I love freezer jam for a number of reasons, number one being that it has a fresh fruit taste compared to canned jam. I also prefer making it because there's no cooking or canning involved, so it's really quick + easy. All you need is berries, sugar, + pectin.
The jam turned out much better this time. My mom always makes freezer jam and it's a treat to have a PBJ when we visit. I was so excited to have some of our own. I used 2 plastic containers she had given me last time I tried making jam and a frosting container, which she also often uses.
An unseasonable treat, but a treat just the same.