Jam Jar Lids - Properly Sealed?

[Rhona]

I've been making tons of jam, and sterilising jars in boiling water, drying in oven, then boiling the jars again when the lids are on.

Some of the jars have a firm, hard top when I press the centre, but a couple of lids have a bit of 'give.' They don't actually pop in and out, but are a bit 'soft.' Are they not sealed properly, do you think?

I'll use the 'soft' ones first, just in case, but do you think it sounds like a problem or not?

[HeyWayne]

I'm guessing they won't be a problem. 'Popping' jars are presumably a recent invention...

[Alison]

Are you filling the jars when the jam is hot? I simply steralise mine (usually in the dishwasher these days), fill while still hot with red hot jam, put the wax circle on top, put the lid on and leave to cool. Label, store and enjoy. As the jam cools the lids are always pulled down a bit and are quite stiff and I'd have thought the only way for this not to happen is if the lids don't seal or they weren't filled hot. You should be OK if you use those jams first but you'll maybe need to check for mould etc before eating, not sure really.

[The Large One]

When SWMBO does here jam she always gets me burning my hands holding the jars whilst they are still hot from the oven
i think she puts them in the oven and heats to 130 degrees i think then puts the jam in straight off the boil
sealing with a good tight lid and whilst the jam cools it pulls the pop lid in
you always know things are going well as a while later whilst in another room you start to here the popping of this happening
if it doen't then some part of your process is not quite right and it may be detremental to the storing of the jam

BTW you are not using plastic lids are you ??

[binley100]

We never worried about popping lids before they were invented so I wouldn't worry too much. Just trust your eyes and nose before you eat anything .

[SarzWix]

How come you're boiling them again when the lids are on? Are they a low sugar recipe or something? If not, and you're using roughly a lb of sugar to a lb of fruit/juice, then they really shouldn't need to be heated again once 'jarred'.

I wouldn't worry too much about them not being indented, possibly, if they're re-used jars, they might not seal as well second time around? Anyway, as long as the lid is on tight - it's as much the sugar doing the preserving really.

[lindyloo]

can i just tag on at the end of this thread to ask about something which has happened with a couple of lids of my latest batch? made jam, and did up lids to biting point, and when part cooled i did them up the rest of the way, but on a couple of them they didnt tighten to a stopping point, they seemed to loosen and continue turning, so what i have done, is put a cellophane wrap over the top of the lids, and sealed with a rubber band. just as an extra precaution. hopefully they will be ok til later on in the autumn, when i start to use them?

[SarzWix]

I think they'll be fine lindyloo

[Alison]

You should really put lids on jams either when it's fully hot or fully cold not part way. I prefer the properly hot method as it forms a vacuum.