Assuming your jams are made with acidic fruits and approved recipes then they will be fine to eat. It is just an appearance issue.

With jams it is usually an indication that the jam was a bit too thick when put into the jars so try jarring it when it is a bit thinner.

You can also defoam the batch prior to jarring it with 1/2 tsp of butter or margarine.

Dave

I love the butter reaction. I used to skim, skim and skim--just about wearing my arm out. A pat of butter and all that is gone. I now keep the butter available every time I start a batch.

Air bubbles just make it look not as pretty, if it bugs you, just turn the jar around.