To avoid food poisoning and stop your stored preserves from developing interesting mould cultures, all jams, marmalades, chutneys and bottled fruit or vegetables should be kept in properly sterilised jars.
You can do this by plunging jars and their lids into boiling water and leaving them there for ten minutes, but I find this extremely messy. I prefer to heat the oven to 150°C, then to place rinsed jars bottom-end-up on a rack in the hot oven, leaving them there for ten minutes or more. (A medicine student friend of my daughter’s, when he heard this, said “interesting: ten minutes at 150 degrees is what we do for surgical instruments too.” Which was sweet of him because I’m sure he wasn’t interested at all.)
The lids, on the other hand, should be put into a small pot of boiling water and boiled hard for ten minutes. This also applies to the rubber rings which make the seal on flip-top canning jars. Remember that vinegar – in chutneys etc – will corrode metal lids, so make sure to use plastic-lined ones for these.
Preserves should then be stored in a cool dark place. Jars must never be opened or tampered with in any way, until you are ready to eat them. Most preserves will last a year at least – in fact, mine sometimes sit around for two years or more and (touch wood) up to now they have never done us any harm. But once a jar is opened, it should always be kept in the fridge. Any contents which develop mould once opened should be thrown out.
© Anne Hanley, 2011