Jam and jelly should be jelled. That's why it's called 'jelly' instead of 'runny'.
The big question when you're making jam is this: How do you know when it's jelled? It's a good question because hot jam is pretty runny. It doesn't fully jell until it's cool. So is there a way to tell if it's going to jell all right when it's still hot?
If you're using pectin and followed the directions you can be reasonably confident that your jam will jell. However, if you've decided not to use pectin, then it's really important to be able to read the jam.
That can be intimidating.
Not to worry! Here are three tests you can do on your jam to see if it's done.
Double Drips. Dip a spoon or spatula into the hot jam and watch as it pours off. Early in the process, it will pour off in a very thin cascade ending in a single drip. As the jam reaches the jell point, it will come off in multiple drips. If those drips hang on the spoon for a bit, then you’ve reached a soft jell stage. When you are sure you are seeing double drips or if the jam begins to come off the spoon very thickly, then the jam is done and ready to bottle.
Sheeting. When jam has reached a very firm jell stage, it will come off the spoon or spatula in a sheet. If your jam sheets off the spoon, it’s done and ready to bottle.
Wrinkle Test. When you start your jam, put a small plate or bowl into the freezer. By the time the jam is done cooking, the plate will be very cold. Drop a small spoonful of the finished jam onto the cold plate and tilt it so the jam runs. The jam will cool fast. Push the jam a bit with the spoon. If the jam has reached the jelling stage, it will wrinkle as you push it. If it wrinkles, the jam is done and you’re ready to bottle it.