Two of my early jam attempts have been delicious but stiff--like hard to get a spoon in stiff. (I just pop the jar in the microwave when I eat them.)

I'll provide some info to help you in determining what I am doing wrong.

These were both made without pectin

1) Pear jam (Linda Ziedrich recipe) I think because my pears were too ripe, I ended up with too much sugar because I stuck to the recipe but probably lost some pear in the processing. I can't remember too much about my cooking process--but I am fairly certain I cooked too long.

2) Blueberry jam (from a book similar to the Ball handbook) Even though this is a low-pectin fruit, this one is stiff too. I simmered a meyer lemon peel in the cooking jam, so that must have added some pectin, but I suspect I also overcooked this.

Overcooking seems the obvious culprit. I think I was so worried about it not gelling that I overcompensated. I used a thermometer, but because my pan is shallow I may not be getting accurate readings. Should the jam be removed from heat as soon as 220 degrees is reached--like that very second? I am also doing plate tests, but because I have never made fresh jams, making them for canning is a mystery.