Trill that's what I've been trying. Not the tapping thing but the clean dry sterile jars, pour in the liquid, seal and turn upside down. Two of them yesterday leaked when I turned them, I sealed them tighter (ow on my poor fingers) and turned them upside down again, they didn't leak but they didn't vacuum. One only had a small amount of jam so i figured maybe there wasn't enough heat to pull it down or something, but the other one was almost full and didn't pop down. I think the jars are just cheap and nasty, I got them from a $2 type shop. So I might check Big W next time I'm there, or gumtree in the mean time.

I wish I'd been saving jars... I will from now on, but my 3kgs of strawberries need to be used before I will have enough jars...

The jams will still be ok won't they? Unsealed? The ones I did yesterday, that didn't pop down? Just means I have to use them now and not keep them?