[Nikkithefoot]

I have had a clear out/up and have uncovered some demijohns that have been in the garden for errrr some years. They will have been exposed to frost, heat, direct sun, rain etc,etc.

Question is will they still be ok to use ie for wine? I'm thinking more around will they have been weakened due to the frosts?

Would I be better chucking them (recycling) and getting new ones as I'm going to start wine making this year again?

Nikki

[Tinbasher]

I have had a clear out/up and have uncovered some demijohns that have been in the garden for errrr some years. They will have been exposed to frost, heat, direct sun, rain etc,etc.

Question is will they still be ok to use ie for wine? I'm thinking more around will they have been weakened due to the frosts?

Would I be better chucking them (recycling) and getting new ones as I'm going to start wine making this year again?

Nikki

I've been given loads over the years from all sorts of sheds and cellars.  Apart from them being filthy, I've never bothered or known what they've been through.  Apart from the 'ear' once snapping off one, I've never had one break yet (touches cricket bat).  Glass is a pretty hardy substance is it not?  Imagine what windows go through, even old ones, and they don't go utterly brittle.

Never use them as a pressure vessel.  Accept that they are not a precision-made container from new.  They can vary quite a bit between one and the next in the size of the bung hole.

[Stripey_cat]

Glass shouldn't be damaged by frosts, unless they were full of water that expanded as it froze (like a burst pipe) - your greenhouse and your windows are fine covered with frost.  Sun and rain are fine, too.

It's not keen on being knocked, though - I tried the cleaning with chain trick, and had a crack propagate right through a jar with such a bang I fell over backwards!  Be reasonably gentle handling them.  The other killer for glass is thermal shock - sudden changes in temperature make it contract or expand unevenly, and again it can suddenly crack in half.  Be careful washing them, that you don't pour boiling water into a cold jar or vice versa.