Do I need to re-jar my chutney?

[throup]

I think I misread that! Congratulations on the impending increase in family size btw.

Thanks. And I see what you mean! I really should read things more thoroughly before I post them.

[vikkib]

I think I misread that! Congratulations on the impending increase in family size btw.

Hehehe! I think I read it the same way!


I've got a question regards the space left at the top of the jars too...

I think I left too much

The lids are on tight and the little poppy bit on the lids have all depressed but there is definitely air in there - not a vaccuum as such. I knocked over a jar the other day and the contents didn't stay in place (as I thought they would if there was a vacuum) but shifted around and the air went to the bottom of the jar.

Is this normal... have I completely misunderstood the way a vacuum works?

[smallblueplanet]

...The lids are on tight and the little poppy bit on the lids have all depressed but there is definitely air in there...

The way I understand it is that the air when a jar is sealed is hot and therefore 'takes up more room'/expands, when it cools down it occupies a smaller volume and therefore outside air pressure 'pushes down' the pop-up bit on the lid. But my O level physics was achieved a long time ago and I might be remembering it wrong?

[vikkib]

The way I understand it is that the air when a jar is sealed is hot and therefore 'takes up more room'/expands, when it cools down it occupies a smaller volume and therefore outside air pressure 'pushes down' the pop-up bit on the lid. But my O level physics was achieved a long time ago and I might be remembering it wrong?

That's what I remembered too but I also thought that that process formed a vacuum... which would mean the contents wouldn't slosh around (yes, that is a scientific and techincal term!)... wiki beckons!

[Alison]

It does form a vacuum in that there is less air on the inside than there would be at normal atmoshperic temperature (cos it was hot and therefore took up more space when you put the lid on) but there is still air there as something has to fill the gap. It'll slosh around if it's runny, if it's more set then it won't, nothing to do with vacuums etc.

[SarzWix]

Having air in the jars shouldn't be a problem. The big bad nasty thing (botulism) develops in anaerobic conditions (low or no oxygen), this is why chutney has to have a certain proportion of sugar and vinegar to the amount of veg because both sugar and acid prevent the development of botulism.

More info here; http://www.uga.edu/nchfp/how/general...ned_foods.html

[Hilary B]

It does form a vacuum in that there is less air on the inside than there would be at normal atmoshperic temperature (cos it was hot and therefore took up more space when you put the lid on) but there is still air there as something has to fill the gap. It'll slosh around if it's runny, if it's more set then it won't, nothing to do with vacuums etc.

Yep! (except that it isn't strictly speaking a vacuum, which means NO air at all)
Even if it was a vaccum, that wouldn't stop things sloshing about if they are 'wet' enough, and fully set jam will stay in an open jar when you turn the jar upside down.